old and new 7 quality control tool

62
1. DEFINITION of 'Quality Control' A process through which a business seeks to ensure that product quality is maintained or improved and manufacturing errors are reduced or eliminated. Quality control requires the business to create an environment in which both management and employees strive for perfection. This is done by training personnel, creating benchmarks for product quality, and testing products to check for statistically significant variations. A major aspect of quality control is the establishment of well-defined controls. These controls help standardize both production and reactions to quality issues. Limiting room for error by specifying which production activities are to be completed by which personnel reduces the chance that employees will be involved in tasks for which they do not have adequate training. . 2. Importance of quality control Quality control is essential to building a successful business that delivers products that meet or exceed customers’ expectations. It also forms the basis of an 1

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Page 1: old and new  7 quality control tool

1 DEFINITION of Quality Control

A process through which a business seeks to ensure that product quality is maintained

or improved and manufacturing errors are reduced or eliminated Quality control

requires the business to create an environment in which both management and

employees strive for perfection This is done by training personnel

creating benchmarks for product quality and testing products to check for statistically

significant variations

A major aspect of quality control is the establishment of well-defined controls These

controls help standardize both production and reactions to quality issues Limiting

room for error by specifying which production activities are to be completed by which

personnel reduces the chance that employees will be involved in tasks for which they

do not have adequate training

2 Importance of quality control

Quality control is essential to building a successful business that delivers products that

meet or exceed customersrsquo expectations It also forms the basis of an efficient

business that minimizes waste and operates at high levels of productivity A quality

control system based on a recognized standard such as ISO 9001 published by the

International Organization for Standardization provides a strong foundation for

achieving a wide range of marketing and operational benefits

3 Competitiveness

The ability to offer customers quality products provides a strong competitive

advantage Quality helps you to win business from competitors who are not able to

match your standards and gives you the opportunity to charge premium prices for a

superior product It can also open new business opportunities in market sectors where

quality is critical

1

4 Customer Loyalty

Providing the market with quality products helps to increase customer satisfaction and

loyalty Satisfied customers have confidence that your products will continue to

provide reliable performance in the future and that increases the likelihood that they

will buy from you again Satisfied customers may also recommend your products to

other companies either directly or by providing testimonials that you can use in your

marketing communications

5 Reputation

Quality makes an important contribution to your companyrsquos reputation particularly

with the growth of social media Customers share their views on products and services

on product review sites and social media such as Face book Positive reviews and

comments can reinforce your own marketing efforts but quality problems can have a

damaging effect on your reputation if the word spreads A major quality issue such as

a product recall may also attract media attention causing further damage

6 Compliance

Compliance with recognized quality standards may be essential for doing business

with certain groups of customers If you are part of a supply chain for example the

lead manufacturer may impose consistent quality standards on all members of the

chain Some customers aim to reduce or eliminate the cost of inspecting incoming

components or materials by insisting that their suppliers implement the same quality

system If you operate in a regulated sector such as chemicals or food you may have

to comply with industry quality standards

7 Costs

2

Quality control can help to reduce your production and product support costs A

quality control system helps to lower levels of waste and rework cutting costs and

improving productivity and production efficiency Delivering quality products can

also reduce the number of returns you have to handle or the cost of repairing or

servicing products in the field

Benefits of Using Quality Control in Manufacturing

The most obvious beneficiary of quality control is the customer who receives a high-

quality product This in turn benefits the company by ensuring customer satisfaction

which leads to repeat business customer loyalty and spreading the word about the

quality of the companys product Therefore quality control in manufacturing pays off

for a company in both reputation and revenue

Companies with quality control procedures in place are far less likely to face product

recalls or safety hazards from poorly constructed products The cost associated with

these recalls can be steep In 2009 Toyota had to recall 124 million cars for sticky

gas pedals and floor mats that could jam accelerators at a cost of approximately $2

billion This could have been avoided had quality control been properly implemented

Methods of quality control

Old 7 tools

Paretochart

Fishbonediagram

Controlchart

Histogram

check sheet

Scatterdiagram

Stratification (flow chart or run chart)

3

4

Feature of this tools

DataorientationFocuson numericaldatameasure andcalculation

New 7 tools

Relationshipdiagram

Treediagram

Arrowdiagram

Affinitydiagram

Matrixdiagram

Matrixdataanalysis diagram

Processdecision programchart(PDPC)

Feature of new quality controls tools

Combineverbalwith numerical

Lookingforrootcause

Clarifyprioritizegoals andschedule

Involveeveryoneinto fullcooperation

Generateideas

5

Now starting with 1st quality control tools

1) Pareto chart or Pareto diagram

A Pareto chart is a bar graph The lengths of the bars represent frequency or cost (time

or money) and are arranged with longest bars on the left and the shortest to the right

In this way the chart visually depicts which situations are more significant

When to Use a Pareto Chart

When analyzing data about the frequency of problems or causes in a process

When there are many problems or causes and you want to focus on the most

significant

When analyzing broad causes by looking at their specific components

When communicating with others about your data

Pareto Chart Procedure

Decide what categories you will use to group items

Decide what measurement is appropriate Common measurements are

frequency quantity cost and time

Decide what period of time the Pareto chart will cover One work cycle One

full day A week

Collect the data recording the category each time (Or assemble data that

already exist)

Subtotal the measurements for each category

Determine the appropriate scale for the measurements you have collected The

maximum value will be the largest subtotal from step 5 (If you will do

optional steps 8 and 9 below the maximum value will be the sum of all

subtotals from step 5) Mark the scale on the left side of the chart

6

Construct and label bars for each category Place the tallest at the far left then

the next tallest to its right and so on If there are many categories with small

measurements they can be grouped as ldquootherrdquo

Steps 8 and 9 are optional but are useful for analysis and communication

Calculate the percentage for each category the subtotal for that category

divided by the total for all categories Draw a right vertical axis and label it

with percentages Be sure the two scales match For example the left

measurement that corresponds to one-half should be exactly opposite 50 on

the right scale

Calculate and draw cumulative sums Add the subtotals for the first and

second categories and place a dot above the second bar indicating that sum

To that sum add the subtotal for the third category and place a dot above the

third bar for that new sum Continue the process for all the bars Connect the

dots starting at the top of the first bar The last dot should reach 100 percent

on the right scale

Pareto Chart Examples

Example 1 shows how many customer complaints were received in each of five

categories

Example 2 takes the largest category ldquodocumentsrdquo from Example 1 breaks it

down into six categories of document-related complaints and shows cumulative

values

If all complaints cause equal distress to the customer working on eliminating

document-related complaints would have the most impact and of those working on

quality certificates should be most fruitful

7

8

2) The fishbone diagram

A Cause-and Effect Diagram also known as fish bone diagram is a tool that shows

systematic relationship between a result or a symptom or an effect and its possible

causes It is an effective tool to systematically generate ideas about causes for

problems and to present these in a structured form This tool was devised by Dr

Kouro Ishikawa and as mentioned earlier is also known as Ishikawa Diagram

Procedure

The steps in the procedure to prepare a cause-and-effect diagram are

1 Agree on the definition of the Effect for which causes are to be found Place the

effect in the dark box at the right Draw the spine or the backbone as a dark line

leading to the box for the effect

1 Determine the main groups or categories of causes Place them in boxes and

connect them through large bones to the backbone

2 Brainstorm to find possible causes and subsidiary causes under each of the main

groups Make sure that the route from the cause to the effect is correctly depicted The

path must start from a root cause and end in the effect

3 After completing all the main groups brainstorm for more causes that may have

escaped earlier

4 Once the diagram is complete discuss relative importance of the causes Short list

the important root causes

9

10

3) Check sheets

Also called defect concentration diagram A check sheet is a structured prepared

form for collecting and analyzing data This is a generic tool that can be adapted for a

wide variety of purposes

When to Use a Check Sheet

When data can be observed and collected repeatedly by the same person or at

the same location

When collecting data on the frequency or patterns of events problems

defects defect location defect causes etc

When collecting data from a production process

Check Sheet Procedure

Decide what event or problem will be observed Develop operational

definitions

Decide when data will be collected and for how long

Design the form Set it up so that data can be recorded simply by making

check marks or Xs or similar symbols and so that data do not have to be

recopied for analysis

Label all spaces on the form

Test the check sheet for a short trial period to be sure it collects the

appropriate data and is easy to use

Each time the targeted event or problem occurs record data on the check

sheet

Check Sheet Example

The figure below shows a check sheet used to collect data on telephone interruptions

The tick marks were added as data was collected over several weeks

11

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 2: old and new  7 quality control tool

4 Customer Loyalty

Providing the market with quality products helps to increase customer satisfaction and

loyalty Satisfied customers have confidence that your products will continue to

provide reliable performance in the future and that increases the likelihood that they

will buy from you again Satisfied customers may also recommend your products to

other companies either directly or by providing testimonials that you can use in your

marketing communications

5 Reputation

Quality makes an important contribution to your companyrsquos reputation particularly

with the growth of social media Customers share their views on products and services

on product review sites and social media such as Face book Positive reviews and

comments can reinforce your own marketing efforts but quality problems can have a

damaging effect on your reputation if the word spreads A major quality issue such as

a product recall may also attract media attention causing further damage

6 Compliance

Compliance with recognized quality standards may be essential for doing business

with certain groups of customers If you are part of a supply chain for example the

lead manufacturer may impose consistent quality standards on all members of the

chain Some customers aim to reduce or eliminate the cost of inspecting incoming

components or materials by insisting that their suppliers implement the same quality

system If you operate in a regulated sector such as chemicals or food you may have

to comply with industry quality standards

7 Costs

2

Quality control can help to reduce your production and product support costs A

quality control system helps to lower levels of waste and rework cutting costs and

improving productivity and production efficiency Delivering quality products can

also reduce the number of returns you have to handle or the cost of repairing or

servicing products in the field

Benefits of Using Quality Control in Manufacturing

The most obvious beneficiary of quality control is the customer who receives a high-

quality product This in turn benefits the company by ensuring customer satisfaction

which leads to repeat business customer loyalty and spreading the word about the

quality of the companys product Therefore quality control in manufacturing pays off

for a company in both reputation and revenue

Companies with quality control procedures in place are far less likely to face product

recalls or safety hazards from poorly constructed products The cost associated with

these recalls can be steep In 2009 Toyota had to recall 124 million cars for sticky

gas pedals and floor mats that could jam accelerators at a cost of approximately $2

billion This could have been avoided had quality control been properly implemented

Methods of quality control

Old 7 tools

Paretochart

Fishbonediagram

Controlchart

Histogram

check sheet

Scatterdiagram

Stratification (flow chart or run chart)

3

4

Feature of this tools

DataorientationFocuson numericaldatameasure andcalculation

New 7 tools

Relationshipdiagram

Treediagram

Arrowdiagram

Affinitydiagram

Matrixdiagram

Matrixdataanalysis diagram

Processdecision programchart(PDPC)

Feature of new quality controls tools

Combineverbalwith numerical

Lookingforrootcause

Clarifyprioritizegoals andschedule

Involveeveryoneinto fullcooperation

Generateideas

5

Now starting with 1st quality control tools

1) Pareto chart or Pareto diagram

A Pareto chart is a bar graph The lengths of the bars represent frequency or cost (time

or money) and are arranged with longest bars on the left and the shortest to the right

In this way the chart visually depicts which situations are more significant

When to Use a Pareto Chart

When analyzing data about the frequency of problems or causes in a process

When there are many problems or causes and you want to focus on the most

significant

When analyzing broad causes by looking at their specific components

When communicating with others about your data

Pareto Chart Procedure

Decide what categories you will use to group items

Decide what measurement is appropriate Common measurements are

frequency quantity cost and time

Decide what period of time the Pareto chart will cover One work cycle One

full day A week

Collect the data recording the category each time (Or assemble data that

already exist)

Subtotal the measurements for each category

Determine the appropriate scale for the measurements you have collected The

maximum value will be the largest subtotal from step 5 (If you will do

optional steps 8 and 9 below the maximum value will be the sum of all

subtotals from step 5) Mark the scale on the left side of the chart

6

Construct and label bars for each category Place the tallest at the far left then

the next tallest to its right and so on If there are many categories with small

measurements they can be grouped as ldquootherrdquo

Steps 8 and 9 are optional but are useful for analysis and communication

Calculate the percentage for each category the subtotal for that category

divided by the total for all categories Draw a right vertical axis and label it

with percentages Be sure the two scales match For example the left

measurement that corresponds to one-half should be exactly opposite 50 on

the right scale

Calculate and draw cumulative sums Add the subtotals for the first and

second categories and place a dot above the second bar indicating that sum

To that sum add the subtotal for the third category and place a dot above the

third bar for that new sum Continue the process for all the bars Connect the

dots starting at the top of the first bar The last dot should reach 100 percent

on the right scale

Pareto Chart Examples

Example 1 shows how many customer complaints were received in each of five

categories

Example 2 takes the largest category ldquodocumentsrdquo from Example 1 breaks it

down into six categories of document-related complaints and shows cumulative

values

If all complaints cause equal distress to the customer working on eliminating

document-related complaints would have the most impact and of those working on

quality certificates should be most fruitful

7

8

2) The fishbone diagram

A Cause-and Effect Diagram also known as fish bone diagram is a tool that shows

systematic relationship between a result or a symptom or an effect and its possible

causes It is an effective tool to systematically generate ideas about causes for

problems and to present these in a structured form This tool was devised by Dr

Kouro Ishikawa and as mentioned earlier is also known as Ishikawa Diagram

Procedure

The steps in the procedure to prepare a cause-and-effect diagram are

1 Agree on the definition of the Effect for which causes are to be found Place the

effect in the dark box at the right Draw the spine or the backbone as a dark line

leading to the box for the effect

1 Determine the main groups or categories of causes Place them in boxes and

connect them through large bones to the backbone

2 Brainstorm to find possible causes and subsidiary causes under each of the main

groups Make sure that the route from the cause to the effect is correctly depicted The

path must start from a root cause and end in the effect

3 After completing all the main groups brainstorm for more causes that may have

escaped earlier

4 Once the diagram is complete discuss relative importance of the causes Short list

the important root causes

9

10

3) Check sheets

Also called defect concentration diagram A check sheet is a structured prepared

form for collecting and analyzing data This is a generic tool that can be adapted for a

wide variety of purposes

When to Use a Check Sheet

When data can be observed and collected repeatedly by the same person or at

the same location

When collecting data on the frequency or patterns of events problems

defects defect location defect causes etc

When collecting data from a production process

Check Sheet Procedure

Decide what event or problem will be observed Develop operational

definitions

Decide when data will be collected and for how long

Design the form Set it up so that data can be recorded simply by making

check marks or Xs or similar symbols and so that data do not have to be

recopied for analysis

Label all spaces on the form

Test the check sheet for a short trial period to be sure it collects the

appropriate data and is easy to use

Each time the targeted event or problem occurs record data on the check

sheet

Check Sheet Example

The figure below shows a check sheet used to collect data on telephone interruptions

The tick marks were added as data was collected over several weeks

11

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 3: old and new  7 quality control tool

Quality control can help to reduce your production and product support costs A

quality control system helps to lower levels of waste and rework cutting costs and

improving productivity and production efficiency Delivering quality products can

also reduce the number of returns you have to handle or the cost of repairing or

servicing products in the field

Benefits of Using Quality Control in Manufacturing

The most obvious beneficiary of quality control is the customer who receives a high-

quality product This in turn benefits the company by ensuring customer satisfaction

which leads to repeat business customer loyalty and spreading the word about the

quality of the companys product Therefore quality control in manufacturing pays off

for a company in both reputation and revenue

Companies with quality control procedures in place are far less likely to face product

recalls or safety hazards from poorly constructed products The cost associated with

these recalls can be steep In 2009 Toyota had to recall 124 million cars for sticky

gas pedals and floor mats that could jam accelerators at a cost of approximately $2

billion This could have been avoided had quality control been properly implemented

Methods of quality control

Old 7 tools

Paretochart

Fishbonediagram

Controlchart

Histogram

check sheet

Scatterdiagram

Stratification (flow chart or run chart)

3

4

Feature of this tools

DataorientationFocuson numericaldatameasure andcalculation

New 7 tools

Relationshipdiagram

Treediagram

Arrowdiagram

Affinitydiagram

Matrixdiagram

Matrixdataanalysis diagram

Processdecision programchart(PDPC)

Feature of new quality controls tools

Combineverbalwith numerical

Lookingforrootcause

Clarifyprioritizegoals andschedule

Involveeveryoneinto fullcooperation

Generateideas

5

Now starting with 1st quality control tools

1) Pareto chart or Pareto diagram

A Pareto chart is a bar graph The lengths of the bars represent frequency or cost (time

or money) and are arranged with longest bars on the left and the shortest to the right

In this way the chart visually depicts which situations are more significant

When to Use a Pareto Chart

When analyzing data about the frequency of problems or causes in a process

When there are many problems or causes and you want to focus on the most

significant

When analyzing broad causes by looking at their specific components

When communicating with others about your data

Pareto Chart Procedure

Decide what categories you will use to group items

Decide what measurement is appropriate Common measurements are

frequency quantity cost and time

Decide what period of time the Pareto chart will cover One work cycle One

full day A week

Collect the data recording the category each time (Or assemble data that

already exist)

Subtotal the measurements for each category

Determine the appropriate scale for the measurements you have collected The

maximum value will be the largest subtotal from step 5 (If you will do

optional steps 8 and 9 below the maximum value will be the sum of all

subtotals from step 5) Mark the scale on the left side of the chart

6

Construct and label bars for each category Place the tallest at the far left then

the next tallest to its right and so on If there are many categories with small

measurements they can be grouped as ldquootherrdquo

Steps 8 and 9 are optional but are useful for analysis and communication

Calculate the percentage for each category the subtotal for that category

divided by the total for all categories Draw a right vertical axis and label it

with percentages Be sure the two scales match For example the left

measurement that corresponds to one-half should be exactly opposite 50 on

the right scale

Calculate and draw cumulative sums Add the subtotals for the first and

second categories and place a dot above the second bar indicating that sum

To that sum add the subtotal for the third category and place a dot above the

third bar for that new sum Continue the process for all the bars Connect the

dots starting at the top of the first bar The last dot should reach 100 percent

on the right scale

Pareto Chart Examples

Example 1 shows how many customer complaints were received in each of five

categories

Example 2 takes the largest category ldquodocumentsrdquo from Example 1 breaks it

down into six categories of document-related complaints and shows cumulative

values

If all complaints cause equal distress to the customer working on eliminating

document-related complaints would have the most impact and of those working on

quality certificates should be most fruitful

7

8

2) The fishbone diagram

A Cause-and Effect Diagram also known as fish bone diagram is a tool that shows

systematic relationship between a result or a symptom or an effect and its possible

causes It is an effective tool to systematically generate ideas about causes for

problems and to present these in a structured form This tool was devised by Dr

Kouro Ishikawa and as mentioned earlier is also known as Ishikawa Diagram

Procedure

The steps in the procedure to prepare a cause-and-effect diagram are

1 Agree on the definition of the Effect for which causes are to be found Place the

effect in the dark box at the right Draw the spine or the backbone as a dark line

leading to the box for the effect

1 Determine the main groups or categories of causes Place them in boxes and

connect them through large bones to the backbone

2 Brainstorm to find possible causes and subsidiary causes under each of the main

groups Make sure that the route from the cause to the effect is correctly depicted The

path must start from a root cause and end in the effect

3 After completing all the main groups brainstorm for more causes that may have

escaped earlier

4 Once the diagram is complete discuss relative importance of the causes Short list

the important root causes

9

10

3) Check sheets

Also called defect concentration diagram A check sheet is a structured prepared

form for collecting and analyzing data This is a generic tool that can be adapted for a

wide variety of purposes

When to Use a Check Sheet

When data can be observed and collected repeatedly by the same person or at

the same location

When collecting data on the frequency or patterns of events problems

defects defect location defect causes etc

When collecting data from a production process

Check Sheet Procedure

Decide what event or problem will be observed Develop operational

definitions

Decide when data will be collected and for how long

Design the form Set it up so that data can be recorded simply by making

check marks or Xs or similar symbols and so that data do not have to be

recopied for analysis

Label all spaces on the form

Test the check sheet for a short trial period to be sure it collects the

appropriate data and is easy to use

Each time the targeted event or problem occurs record data on the check

sheet

Check Sheet Example

The figure below shows a check sheet used to collect data on telephone interruptions

The tick marks were added as data was collected over several weeks

11

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 4: old and new  7 quality control tool

4

Feature of this tools

DataorientationFocuson numericaldatameasure andcalculation

New 7 tools

Relationshipdiagram

Treediagram

Arrowdiagram

Affinitydiagram

Matrixdiagram

Matrixdataanalysis diagram

Processdecision programchart(PDPC)

Feature of new quality controls tools

Combineverbalwith numerical

Lookingforrootcause

Clarifyprioritizegoals andschedule

Involveeveryoneinto fullcooperation

Generateideas

5

Now starting with 1st quality control tools

1) Pareto chart or Pareto diagram

A Pareto chart is a bar graph The lengths of the bars represent frequency or cost (time

or money) and are arranged with longest bars on the left and the shortest to the right

In this way the chart visually depicts which situations are more significant

When to Use a Pareto Chart

When analyzing data about the frequency of problems or causes in a process

When there are many problems or causes and you want to focus on the most

significant

When analyzing broad causes by looking at their specific components

When communicating with others about your data

Pareto Chart Procedure

Decide what categories you will use to group items

Decide what measurement is appropriate Common measurements are

frequency quantity cost and time

Decide what period of time the Pareto chart will cover One work cycle One

full day A week

Collect the data recording the category each time (Or assemble data that

already exist)

Subtotal the measurements for each category

Determine the appropriate scale for the measurements you have collected The

maximum value will be the largest subtotal from step 5 (If you will do

optional steps 8 and 9 below the maximum value will be the sum of all

subtotals from step 5) Mark the scale on the left side of the chart

6

Construct and label bars for each category Place the tallest at the far left then

the next tallest to its right and so on If there are many categories with small

measurements they can be grouped as ldquootherrdquo

Steps 8 and 9 are optional but are useful for analysis and communication

Calculate the percentage for each category the subtotal for that category

divided by the total for all categories Draw a right vertical axis and label it

with percentages Be sure the two scales match For example the left

measurement that corresponds to one-half should be exactly opposite 50 on

the right scale

Calculate and draw cumulative sums Add the subtotals for the first and

second categories and place a dot above the second bar indicating that sum

To that sum add the subtotal for the third category and place a dot above the

third bar for that new sum Continue the process for all the bars Connect the

dots starting at the top of the first bar The last dot should reach 100 percent

on the right scale

Pareto Chart Examples

Example 1 shows how many customer complaints were received in each of five

categories

Example 2 takes the largest category ldquodocumentsrdquo from Example 1 breaks it

down into six categories of document-related complaints and shows cumulative

values

If all complaints cause equal distress to the customer working on eliminating

document-related complaints would have the most impact and of those working on

quality certificates should be most fruitful

7

8

2) The fishbone diagram

A Cause-and Effect Diagram also known as fish bone diagram is a tool that shows

systematic relationship between a result or a symptom or an effect and its possible

causes It is an effective tool to systematically generate ideas about causes for

problems and to present these in a structured form This tool was devised by Dr

Kouro Ishikawa and as mentioned earlier is also known as Ishikawa Diagram

Procedure

The steps in the procedure to prepare a cause-and-effect diagram are

1 Agree on the definition of the Effect for which causes are to be found Place the

effect in the dark box at the right Draw the spine or the backbone as a dark line

leading to the box for the effect

1 Determine the main groups or categories of causes Place them in boxes and

connect them through large bones to the backbone

2 Brainstorm to find possible causes and subsidiary causes under each of the main

groups Make sure that the route from the cause to the effect is correctly depicted The

path must start from a root cause and end in the effect

3 After completing all the main groups brainstorm for more causes that may have

escaped earlier

4 Once the diagram is complete discuss relative importance of the causes Short list

the important root causes

9

10

3) Check sheets

Also called defect concentration diagram A check sheet is a structured prepared

form for collecting and analyzing data This is a generic tool that can be adapted for a

wide variety of purposes

When to Use a Check Sheet

When data can be observed and collected repeatedly by the same person or at

the same location

When collecting data on the frequency or patterns of events problems

defects defect location defect causes etc

When collecting data from a production process

Check Sheet Procedure

Decide what event or problem will be observed Develop operational

definitions

Decide when data will be collected and for how long

Design the form Set it up so that data can be recorded simply by making

check marks or Xs or similar symbols and so that data do not have to be

recopied for analysis

Label all spaces on the form

Test the check sheet for a short trial period to be sure it collects the

appropriate data and is easy to use

Each time the targeted event or problem occurs record data on the check

sheet

Check Sheet Example

The figure below shows a check sheet used to collect data on telephone interruptions

The tick marks were added as data was collected over several weeks

11

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 5: old and new  7 quality control tool

Feature of this tools

DataorientationFocuson numericaldatameasure andcalculation

New 7 tools

Relationshipdiagram

Treediagram

Arrowdiagram

Affinitydiagram

Matrixdiagram

Matrixdataanalysis diagram

Processdecision programchart(PDPC)

Feature of new quality controls tools

Combineverbalwith numerical

Lookingforrootcause

Clarifyprioritizegoals andschedule

Involveeveryoneinto fullcooperation

Generateideas

5

Now starting with 1st quality control tools

1) Pareto chart or Pareto diagram

A Pareto chart is a bar graph The lengths of the bars represent frequency or cost (time

or money) and are arranged with longest bars on the left and the shortest to the right

In this way the chart visually depicts which situations are more significant

When to Use a Pareto Chart

When analyzing data about the frequency of problems or causes in a process

When there are many problems or causes and you want to focus on the most

significant

When analyzing broad causes by looking at their specific components

When communicating with others about your data

Pareto Chart Procedure

Decide what categories you will use to group items

Decide what measurement is appropriate Common measurements are

frequency quantity cost and time

Decide what period of time the Pareto chart will cover One work cycle One

full day A week

Collect the data recording the category each time (Or assemble data that

already exist)

Subtotal the measurements for each category

Determine the appropriate scale for the measurements you have collected The

maximum value will be the largest subtotal from step 5 (If you will do

optional steps 8 and 9 below the maximum value will be the sum of all

subtotals from step 5) Mark the scale on the left side of the chart

6

Construct and label bars for each category Place the tallest at the far left then

the next tallest to its right and so on If there are many categories with small

measurements they can be grouped as ldquootherrdquo

Steps 8 and 9 are optional but are useful for analysis and communication

Calculate the percentage for each category the subtotal for that category

divided by the total for all categories Draw a right vertical axis and label it

with percentages Be sure the two scales match For example the left

measurement that corresponds to one-half should be exactly opposite 50 on

the right scale

Calculate and draw cumulative sums Add the subtotals for the first and

second categories and place a dot above the second bar indicating that sum

To that sum add the subtotal for the third category and place a dot above the

third bar for that new sum Continue the process for all the bars Connect the

dots starting at the top of the first bar The last dot should reach 100 percent

on the right scale

Pareto Chart Examples

Example 1 shows how many customer complaints were received in each of five

categories

Example 2 takes the largest category ldquodocumentsrdquo from Example 1 breaks it

down into six categories of document-related complaints and shows cumulative

values

If all complaints cause equal distress to the customer working on eliminating

document-related complaints would have the most impact and of those working on

quality certificates should be most fruitful

7

8

2) The fishbone diagram

A Cause-and Effect Diagram also known as fish bone diagram is a tool that shows

systematic relationship between a result or a symptom or an effect and its possible

causes It is an effective tool to systematically generate ideas about causes for

problems and to present these in a structured form This tool was devised by Dr

Kouro Ishikawa and as mentioned earlier is also known as Ishikawa Diagram

Procedure

The steps in the procedure to prepare a cause-and-effect diagram are

1 Agree on the definition of the Effect for which causes are to be found Place the

effect in the dark box at the right Draw the spine or the backbone as a dark line

leading to the box for the effect

1 Determine the main groups or categories of causes Place them in boxes and

connect them through large bones to the backbone

2 Brainstorm to find possible causes and subsidiary causes under each of the main

groups Make sure that the route from the cause to the effect is correctly depicted The

path must start from a root cause and end in the effect

3 After completing all the main groups brainstorm for more causes that may have

escaped earlier

4 Once the diagram is complete discuss relative importance of the causes Short list

the important root causes

9

10

3) Check sheets

Also called defect concentration diagram A check sheet is a structured prepared

form for collecting and analyzing data This is a generic tool that can be adapted for a

wide variety of purposes

When to Use a Check Sheet

When data can be observed and collected repeatedly by the same person or at

the same location

When collecting data on the frequency or patterns of events problems

defects defect location defect causes etc

When collecting data from a production process

Check Sheet Procedure

Decide what event or problem will be observed Develop operational

definitions

Decide when data will be collected and for how long

Design the form Set it up so that data can be recorded simply by making

check marks or Xs or similar symbols and so that data do not have to be

recopied for analysis

Label all spaces on the form

Test the check sheet for a short trial period to be sure it collects the

appropriate data and is easy to use

Each time the targeted event or problem occurs record data on the check

sheet

Check Sheet Example

The figure below shows a check sheet used to collect data on telephone interruptions

The tick marks were added as data was collected over several weeks

11

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 6: old and new  7 quality control tool

Now starting with 1st quality control tools

1) Pareto chart or Pareto diagram

A Pareto chart is a bar graph The lengths of the bars represent frequency or cost (time

or money) and are arranged with longest bars on the left and the shortest to the right

In this way the chart visually depicts which situations are more significant

When to Use a Pareto Chart

When analyzing data about the frequency of problems or causes in a process

When there are many problems or causes and you want to focus on the most

significant

When analyzing broad causes by looking at their specific components

When communicating with others about your data

Pareto Chart Procedure

Decide what categories you will use to group items

Decide what measurement is appropriate Common measurements are

frequency quantity cost and time

Decide what period of time the Pareto chart will cover One work cycle One

full day A week

Collect the data recording the category each time (Or assemble data that

already exist)

Subtotal the measurements for each category

Determine the appropriate scale for the measurements you have collected The

maximum value will be the largest subtotal from step 5 (If you will do

optional steps 8 and 9 below the maximum value will be the sum of all

subtotals from step 5) Mark the scale on the left side of the chart

6

Construct and label bars for each category Place the tallest at the far left then

the next tallest to its right and so on If there are many categories with small

measurements they can be grouped as ldquootherrdquo

Steps 8 and 9 are optional but are useful for analysis and communication

Calculate the percentage for each category the subtotal for that category

divided by the total for all categories Draw a right vertical axis and label it

with percentages Be sure the two scales match For example the left

measurement that corresponds to one-half should be exactly opposite 50 on

the right scale

Calculate and draw cumulative sums Add the subtotals for the first and

second categories and place a dot above the second bar indicating that sum

To that sum add the subtotal for the third category and place a dot above the

third bar for that new sum Continue the process for all the bars Connect the

dots starting at the top of the first bar The last dot should reach 100 percent

on the right scale

Pareto Chart Examples

Example 1 shows how many customer complaints were received in each of five

categories

Example 2 takes the largest category ldquodocumentsrdquo from Example 1 breaks it

down into six categories of document-related complaints and shows cumulative

values

If all complaints cause equal distress to the customer working on eliminating

document-related complaints would have the most impact and of those working on

quality certificates should be most fruitful

7

8

2) The fishbone diagram

A Cause-and Effect Diagram also known as fish bone diagram is a tool that shows

systematic relationship between a result or a symptom or an effect and its possible

causes It is an effective tool to systematically generate ideas about causes for

problems and to present these in a structured form This tool was devised by Dr

Kouro Ishikawa and as mentioned earlier is also known as Ishikawa Diagram

Procedure

The steps in the procedure to prepare a cause-and-effect diagram are

1 Agree on the definition of the Effect for which causes are to be found Place the

effect in the dark box at the right Draw the spine or the backbone as a dark line

leading to the box for the effect

1 Determine the main groups or categories of causes Place them in boxes and

connect them through large bones to the backbone

2 Brainstorm to find possible causes and subsidiary causes under each of the main

groups Make sure that the route from the cause to the effect is correctly depicted The

path must start from a root cause and end in the effect

3 After completing all the main groups brainstorm for more causes that may have

escaped earlier

4 Once the diagram is complete discuss relative importance of the causes Short list

the important root causes

9

10

3) Check sheets

Also called defect concentration diagram A check sheet is a structured prepared

form for collecting and analyzing data This is a generic tool that can be adapted for a

wide variety of purposes

When to Use a Check Sheet

When data can be observed and collected repeatedly by the same person or at

the same location

When collecting data on the frequency or patterns of events problems

defects defect location defect causes etc

When collecting data from a production process

Check Sheet Procedure

Decide what event or problem will be observed Develop operational

definitions

Decide when data will be collected and for how long

Design the form Set it up so that data can be recorded simply by making

check marks or Xs or similar symbols and so that data do not have to be

recopied for analysis

Label all spaces on the form

Test the check sheet for a short trial period to be sure it collects the

appropriate data and is easy to use

Each time the targeted event or problem occurs record data on the check

sheet

Check Sheet Example

The figure below shows a check sheet used to collect data on telephone interruptions

The tick marks were added as data was collected over several weeks

11

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 7: old and new  7 quality control tool

Construct and label bars for each category Place the tallest at the far left then

the next tallest to its right and so on If there are many categories with small

measurements they can be grouped as ldquootherrdquo

Steps 8 and 9 are optional but are useful for analysis and communication

Calculate the percentage for each category the subtotal for that category

divided by the total for all categories Draw a right vertical axis and label it

with percentages Be sure the two scales match For example the left

measurement that corresponds to one-half should be exactly opposite 50 on

the right scale

Calculate and draw cumulative sums Add the subtotals for the first and

second categories and place a dot above the second bar indicating that sum

To that sum add the subtotal for the third category and place a dot above the

third bar for that new sum Continue the process for all the bars Connect the

dots starting at the top of the first bar The last dot should reach 100 percent

on the right scale

Pareto Chart Examples

Example 1 shows how many customer complaints were received in each of five

categories

Example 2 takes the largest category ldquodocumentsrdquo from Example 1 breaks it

down into six categories of document-related complaints and shows cumulative

values

If all complaints cause equal distress to the customer working on eliminating

document-related complaints would have the most impact and of those working on

quality certificates should be most fruitful

7

8

2) The fishbone diagram

A Cause-and Effect Diagram also known as fish bone diagram is a tool that shows

systematic relationship between a result or a symptom or an effect and its possible

causes It is an effective tool to systematically generate ideas about causes for

problems and to present these in a structured form This tool was devised by Dr

Kouro Ishikawa and as mentioned earlier is also known as Ishikawa Diagram

Procedure

The steps in the procedure to prepare a cause-and-effect diagram are

1 Agree on the definition of the Effect for which causes are to be found Place the

effect in the dark box at the right Draw the spine or the backbone as a dark line

leading to the box for the effect

1 Determine the main groups or categories of causes Place them in boxes and

connect them through large bones to the backbone

2 Brainstorm to find possible causes and subsidiary causes under each of the main

groups Make sure that the route from the cause to the effect is correctly depicted The

path must start from a root cause and end in the effect

3 After completing all the main groups brainstorm for more causes that may have

escaped earlier

4 Once the diagram is complete discuss relative importance of the causes Short list

the important root causes

9

10

3) Check sheets

Also called defect concentration diagram A check sheet is a structured prepared

form for collecting and analyzing data This is a generic tool that can be adapted for a

wide variety of purposes

When to Use a Check Sheet

When data can be observed and collected repeatedly by the same person or at

the same location

When collecting data on the frequency or patterns of events problems

defects defect location defect causes etc

When collecting data from a production process

Check Sheet Procedure

Decide what event or problem will be observed Develop operational

definitions

Decide when data will be collected and for how long

Design the form Set it up so that data can be recorded simply by making

check marks or Xs or similar symbols and so that data do not have to be

recopied for analysis

Label all spaces on the form

Test the check sheet for a short trial period to be sure it collects the

appropriate data and is easy to use

Each time the targeted event or problem occurs record data on the check

sheet

Check Sheet Example

The figure below shows a check sheet used to collect data on telephone interruptions

The tick marks were added as data was collected over several weeks

11

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 8: old and new  7 quality control tool

8

2) The fishbone diagram

A Cause-and Effect Diagram also known as fish bone diagram is a tool that shows

systematic relationship between a result or a symptom or an effect and its possible

causes It is an effective tool to systematically generate ideas about causes for

problems and to present these in a structured form This tool was devised by Dr

Kouro Ishikawa and as mentioned earlier is also known as Ishikawa Diagram

Procedure

The steps in the procedure to prepare a cause-and-effect diagram are

1 Agree on the definition of the Effect for which causes are to be found Place the

effect in the dark box at the right Draw the spine or the backbone as a dark line

leading to the box for the effect

1 Determine the main groups or categories of causes Place them in boxes and

connect them through large bones to the backbone

2 Brainstorm to find possible causes and subsidiary causes under each of the main

groups Make sure that the route from the cause to the effect is correctly depicted The

path must start from a root cause and end in the effect

3 After completing all the main groups brainstorm for more causes that may have

escaped earlier

4 Once the diagram is complete discuss relative importance of the causes Short list

the important root causes

9

10

3) Check sheets

Also called defect concentration diagram A check sheet is a structured prepared

form for collecting and analyzing data This is a generic tool that can be adapted for a

wide variety of purposes

When to Use a Check Sheet

When data can be observed and collected repeatedly by the same person or at

the same location

When collecting data on the frequency or patterns of events problems

defects defect location defect causes etc

When collecting data from a production process

Check Sheet Procedure

Decide what event or problem will be observed Develop operational

definitions

Decide when data will be collected and for how long

Design the form Set it up so that data can be recorded simply by making

check marks or Xs or similar symbols and so that data do not have to be

recopied for analysis

Label all spaces on the form

Test the check sheet for a short trial period to be sure it collects the

appropriate data and is easy to use

Each time the targeted event or problem occurs record data on the check

sheet

Check Sheet Example

The figure below shows a check sheet used to collect data on telephone interruptions

The tick marks were added as data was collected over several weeks

11

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 9: old and new  7 quality control tool

2) The fishbone diagram

A Cause-and Effect Diagram also known as fish bone diagram is a tool that shows

systematic relationship between a result or a symptom or an effect and its possible

causes It is an effective tool to systematically generate ideas about causes for

problems and to present these in a structured form This tool was devised by Dr

Kouro Ishikawa and as mentioned earlier is also known as Ishikawa Diagram

Procedure

The steps in the procedure to prepare a cause-and-effect diagram are

1 Agree on the definition of the Effect for which causes are to be found Place the

effect in the dark box at the right Draw the spine or the backbone as a dark line

leading to the box for the effect

1 Determine the main groups or categories of causes Place them in boxes and

connect them through large bones to the backbone

2 Brainstorm to find possible causes and subsidiary causes under each of the main

groups Make sure that the route from the cause to the effect is correctly depicted The

path must start from a root cause and end in the effect

3 After completing all the main groups brainstorm for more causes that may have

escaped earlier

4 Once the diagram is complete discuss relative importance of the causes Short list

the important root causes

9

10

3) Check sheets

Also called defect concentration diagram A check sheet is a structured prepared

form for collecting and analyzing data This is a generic tool that can be adapted for a

wide variety of purposes

When to Use a Check Sheet

When data can be observed and collected repeatedly by the same person or at

the same location

When collecting data on the frequency or patterns of events problems

defects defect location defect causes etc

When collecting data from a production process

Check Sheet Procedure

Decide what event or problem will be observed Develop operational

definitions

Decide when data will be collected and for how long

Design the form Set it up so that data can be recorded simply by making

check marks or Xs or similar symbols and so that data do not have to be

recopied for analysis

Label all spaces on the form

Test the check sheet for a short trial period to be sure it collects the

appropriate data and is easy to use

Each time the targeted event or problem occurs record data on the check

sheet

Check Sheet Example

The figure below shows a check sheet used to collect data on telephone interruptions

The tick marks were added as data was collected over several weeks

11

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 10: old and new  7 quality control tool

10

3) Check sheets

Also called defect concentration diagram A check sheet is a structured prepared

form for collecting and analyzing data This is a generic tool that can be adapted for a

wide variety of purposes

When to Use a Check Sheet

When data can be observed and collected repeatedly by the same person or at

the same location

When collecting data on the frequency or patterns of events problems

defects defect location defect causes etc

When collecting data from a production process

Check Sheet Procedure

Decide what event or problem will be observed Develop operational

definitions

Decide when data will be collected and for how long

Design the form Set it up so that data can be recorded simply by making

check marks or Xs or similar symbols and so that data do not have to be

recopied for analysis

Label all spaces on the form

Test the check sheet for a short trial period to be sure it collects the

appropriate data and is easy to use

Each time the targeted event or problem occurs record data on the check

sheet

Check Sheet Example

The figure below shows a check sheet used to collect data on telephone interruptions

The tick marks were added as data was collected over several weeks

11

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 11: old and new  7 quality control tool

3) Check sheets

Also called defect concentration diagram A check sheet is a structured prepared

form for collecting and analyzing data This is a generic tool that can be adapted for a

wide variety of purposes

When to Use a Check Sheet

When data can be observed and collected repeatedly by the same person or at

the same location

When collecting data on the frequency or patterns of events problems

defects defect location defect causes etc

When collecting data from a production process

Check Sheet Procedure

Decide what event or problem will be observed Develop operational

definitions

Decide when data will be collected and for how long

Design the form Set it up so that data can be recorded simply by making

check marks or Xs or similar symbols and so that data do not have to be

recopied for analysis

Label all spaces on the form

Test the check sheet for a short trial period to be sure it collects the

appropriate data and is easy to use

Each time the targeted event or problem occurs record data on the check

sheet

Check Sheet Example

The figure below shows a check sheet used to collect data on telephone interruptions

The tick marks were added as data was collected over several weeks

11

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 12: old and new  7 quality control tool

12

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 13: old and new  7 quality control tool

4) Control chart

The control chart is a graph used to study how a process changes over time Data are

plotted in time order A control chart always has a central line for the average an

upper line for the upper control limit and a lower line for the lower control limit

These lines are determined from historical data By comparing current data to these

lines you can draw conclusions about whether the process variation is consistent (in

control) or is unpredictable (out of control affected by special causes of variation)

Control charts for variable data are used in pairs The top chart monitors the average

or the centring of the distribution of data from the process The bottom chart monitors

the range or the width of the distribution If your data were shots in target practice

the average is where the shots are clustering and the range is how tightly they are

clustered Control charts for attribute data are used singly

41 When to Use a Control Chart

When controlling ongoing processes by finding and correcting problems as they

occur

When predicting the expected range of outcomes from a process

When determining whether a process is stable (in statistical control)

When analyzing patterns of process variation from special causes (non-routine

events) or common causes (built into the process)

When determining whether your quality improvement project should aim to

prevent specific problems or to make fundamental changes to the process

Control Chart Basic Procedure

Choose the appropriate control chart for your data

Determine the appropriate time period for collecting and plotting data

13

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 14: old and new  7 quality control tool

Collect data construct your chart and analyze the data

Look for ldquoout-of-control signalsrdquo on the control chart When one is identified mark it

on the chart and investigate the cause Document how you investigated what you

learned the cause and how it was corrected

Out-of-control signals

A single point outside the control limits In Figure 1 point sixteen is above the UCL

(upper control limit)

Two out of three successive points are on the same side of the centreline and farther

than 2 σ from it In Figure 1 point 4 sends that signal

Four out of five successive points are on the same side of the centreline and farther

than 1 σ from it In Figure 1 point 11 sends that signal

A run of eight in a row are on the same side of the centreline Or 10 out of 11 12 out

of 14 or 16 out of 20 In Figure 1 point 21 is eighth in a row above the centreline

Obvious consistent or persistent patterns that suggest something unusual about your

data and your process

5 Continue to plot data as they are generated As each new data point is plotted

check for new out-of-control signals

14

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 15: old and new  7 quality control tool

6 When you start a new control chart the process may be out of control If so the

control limits calculated from the first 20 points are conditional limits When you

have at least 20 sequential points from a period when the process is operating in

control recalculate control limits

5) Histogram chart

A frequency distribution shows how often each different value in a set of data occurs

A histogram is the most commonly used graph to show frequency distributions It

looks very much like a bar chart but there are important differences between them

When to Use a Histogram

When the data are numerical

When you want to see the shape of the datarsquos distribution especially when

determining whether the output of a process is distributed approximately

normally

When analyzing whether a process can meet the customerrsquos requirements

When analyzing what the output from a supplierrsquos process looks like

When seeing whether a process change has occurred from one time period to

another

When determining whether the outputs of two or more processes are different

When you wish to communicate the distribution of data quickly and easily to

others

Histogram Construction

Collect at least 50 consecutive data points from a process

Use the histogram worksheet to set up the histogram It will help you determine the

number of bars the range of numbers that go into each bar and the labels for the bar

edges After calculating W in step 2 of the worksheet use your judgment to adjust it

to a convenient number For example you might decide to round 09 to an even 10

15

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 16: old and new  7 quality control tool

The value for W must not have more decimal places than the numbers you will be

graphing

Draw x- and y-axes on graph paper Mark and label the y-axis for counting data

values Mark and label the x-axis with the L values from the worksheet The spaces

between these numbers will be the bars of the histogram Do not allow for spaces

between bars

For each data point mark off one count above the appropriate bar with an X or by

shading that portion of the bar

Histogram Analysis

Before drawing any conclusions from your histogram satisfy yourself that the process

was operating normally during the time period being studied If any unusual events

affected the process during the time period of the histogram your analysis of the

histogram shape probably cannot be generalized to all time periods

Analyze the meaning of your histogramrsquo

16

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 17: old and new  7 quality control tool

17

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 18: old and new  7 quality control tool

6) Scatter chart

The scatter diagram graphs pairs of numerical data with one variable on each axis to

look for a relationship between them If the variables are correlated the points will

fall along a line or curve The better the correlation the tighter the points will hug the

line

When to Use a Scatter Diagram

When you have paired numerical data

When your dependent variable may have multiple values for each value of your

independent variable

When trying to determine whether the two variables are related such ashellip

When trying to identify potential root causes of problems

After brainstorming causes and effects using a fishbone diagram to determine

objectively whether a particular cause and effect are related

When determining whether two effects that appears to be related both occur with the

same cause

When testing for autocorrelation before constructing a control chart

Scatter Diagram Procedure

Collect pairs of data where a relationship is suspected

Draw a graph with the independent variable on the horizontal axis and the dependent

variable on the vertical axis For each pair of data put a dot or a symbol where the x-

axis value intersects the y-axis value (If two dots fall together put them side by side

touching so that you can see both)

18

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 19: old and new  7 quality control tool

Look at the pattern of points to see if a relationship is obvious If the data clearly form

a line or a curve you may stop The variables are correlated You may wish to use

regression or correlation analysis now Otherwise complete steps 4 through 7

Divide points on the graph into four quadrants If there are X points on the graph

Count X2 points from top to bottom and draw a horizontal line

Count X2 points from left to right and draw a vertical line

If number of points is odd draw the line through the middle point

Count the points in each quadrant Do not count points on a line

Add the diagonally opposite quadrants Find the smaller sum and the total of points in

all quadrants

A = points in upper left + points in lower right

B = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

Look up the limit for N on the trend test table

If Q is less than the limit the two variables are related

If Q is greater than or equal to the limit the pattern could have occurred from random

chance

19

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 20: old and new  7 quality control tool

Scatter Diagram Example

The ZZ-400 manufacturing team suspects a relationship between product purity

(percent purity) and the amount of iron (measured in parts per million or ppm) Purity

and iron are plotted against each other as a scatter diagram as shown in the figure

below

There are 24 data points Median lines are drawn so that 12 points fall on each side for

both percent purity and ppm iron

To test for a relationship they calculate

A = points in upper left + points in lower right = 9 + 9 = 18

B = points in upper right + points in lower left = 3 + 3 = 6

Q = the smaller of A and B = the smaller of 18 and 6 = 6

N = A + B = 18 + 6 = 24

20

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 21: old and new  7 quality control tool

Then they look up the limit for N on the trend test table For N = 24 the limit is 6

Q is equal to the limit Therefore the pattern could have occurred from random

chance and no relationship is demonstrated

Scatter Diagram Example

Scatter Diagram Considerations

Here are some examples of situations in which might you use a scatter diagram

Variable A is the temperature of a reaction after 15 minutes Variable B measures the

colour of the product You suspect higher temperature makes the product darker Plot

temperature and colour on a scatter diagram

Variable A is the number of employees trained on new software and variable B is the

number of calls to the computer helps line You suspect that more training reduces the

number of calls Plot number of people trained versus number of calls

To test for autocorrelation of a measurement being monitored on a control chart plot

this pair of variables Variable A is the measurement at a given time Variable B is the

same measurement but at the previous time If the scatter diagram shows correlation

do another diagram where variable B is the measurement two times previously Keep

increasing the separation between the two times until the scatter diagram shows no

correlation

21

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 22: old and new  7 quality control tool

Even if the scatter diagram shows a relationship do not assume that one variable

caused the other Both may be influenced by a third variable

When the data are plotted the more the diagram resembles a straight line the stronger

the relationship

If a line is not clear statistics (N and Q) determine whether there is reasonable

certainty that a relationship exists If the statistics say that no relationship exists the

pattern could have occurred by random chance

If the scatter diagram shows no relationship between the variables consider whether

the data might be stratified

If the diagram shows no relationship consider whether the independent (x-axis)

variable has been varied widely Sometimes a relationship is not apparent because the

data donrsquot cover a wide enough range

Think creatively about how to use scatter diagrams to discover a root cause

Drawing a scatter diagram is the first step in looking for a relationship between

variables

22

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 23: old and new  7 quality control tool

7) Stratification

Stratification is a technique used in combination with other data analysis tools When

data from a variety of sources or categories have been lumped together the meaning

of the data can be impossible to see This technique separates the data so that patterns

can be seen

When to Use Stratification

Before collecting data

When data come from several sources or conditions such as shifts days of the

week suppliers or population groups

When data analysis may require separating different sources or conditions

Stratification Procedure

Before collecting data consider which information about the sources of the data

might have an effect on the results Set up the data collection so that you collect that

information as well

When plotting or graphing the collected data on a scatter diagram control chart

histogram or other analysis tool use different marks or colours to distinguish data

from various sources Data that are distinguished in this way are said to be

ldquostratifiedrdquo

Analyze the subsets of stratified data separately For example on a scatter diagram

where data are stratified into data from source 1 and data from source 2 draw

quadrants count points and determine the critical value only for the data from source

1 then only for the data from source 2

Stratification Example

23

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 24: old and new  7 quality control tool

The ZZndash400 manufacturing team drew a scatter diagram to test whether product

purity and iron contamination were related but the plot did not demonstrate a

relationship Then a team member realized that the data came from three different

reactors The team member redrew the diagram using a different symbol for each

reactorrsquos data

Now patterns can be seen The data from reactor 2 and reactor 3 are circled Even

without doing any calculations it is clear that for those two reactors purity decreases

as iron increases However the data from reactor 1 the solid dots that are not circled

do not show that relationship Something is different about reactor 1

Stratification Considerations

Here are examples of different sources that might require data to be stratified

Equipment

Shifts

Departments

24

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 25: old and new  7 quality control tool

Materials

Suppliers

Day of the week

Time of day

Products

Survey data usually benefit from stratification

Always consider before collecting data whether stratification might be needed during

analysis Plan to collect stratification information After the data are collected it might

be too late

On your graph or chart include a legend that identifies the marks or colours used

25

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 26: old and new  7 quality control tool

Now starting with new 7 quality control tool

Need of new quality control tool

Many customer requirements cannot always be adequately expressed by numerical

data alone Nevertheless even verbal statements can be expressions of facts because

it represents facts we ought to use Verbal data as well as numerical data in

controlling the managing quality It provides both quality control as well as

improvement during the manufacturing process

Benefits of new 7 quality control tool

Combine verbal with Numerical data

Looking for root cause

Clarify prioritize goals and schedule

Involve everyone into full cooperation and generate new ideas 1048577

The first new quality control tool is

1) Affinity Diagram

Application

An affinity diagram is used to organize into groupings large number of ideas opinions

or concerns about a Particular topic

Description

When a large number of ideas opinions or other concerns about a particular topic are

being collected this tool organizes the information into grouping~~based on the

natural relationships that exist among them The process is designed to stimulate

creativity and full participation It works best in groups of limited Size (a maximum

26

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 27: old and new  7 quality control tool

of eight members is recommended) in which members are accustomed to working

together This tool is often used to organize ideas generated by brainstorming

Procedure

State the topic to be studied in broad terms(details may prejudice the

response)

Record as many individual ideas opinions or concerns as possible on cards

(one per

card)

Mix the cards and spread them randomly on a large table

Group related cards together as follows

a)sort cards that seem to be related into groups and

b) limit number of grouping to ten without forcing single cards into groups

Locate or create a header card that captures the meaning of each group

Place this header card on top

Transfer the information from cards onto paper organized by groupings

Example For next generation digital camera we can organize the customer

Complains and requirements in an Affinity Diagram1048577

27

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 28: old and new  7 quality control tool

Affinity diagram

28

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 29: old and new  7 quality control tool

2) Tree diagram

Application

A tree diagram is used to show the interrelation between a topic and its component

elements

Description

A tree diagram systematically breaks down a topic into its component elements Ideas

generated by

Brainstorming and graphed or clustered with an affinity diagram can be converted

into a tree diagram

to show logical and sequential links This tool can be used in planning and problem

solving

Procedure

State the topic to be studied clearly

Define the major categories of the topic(brainstorm or use the header cards

from the affinity diagram)

Construct the diagram by placing the topic in a box on the left-hand side

Branch the major categories laterally to the right

For each major category define the component elements and sub-elements if

any

Laterally branch to the right the component elements and sub-elements for

each major category and

Review the diagram to ensure that there are no gaps in either sequence or

logic

29

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 30: old and new  7 quality control tool

30

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 31: old and new  7 quality control tool

3) Arrow diagram

Purpose To create a visual presentation of the steps of a process or tasks necessary to

complete a project with special emphasis on the time taken for these activities

Procedure

1 List all the tasks or activities needed to be accomplished before the process of the

project

2 Decide which steps are undertaken in series and which steps can be run in parallel

Arrange the

Activities in a proper sequence

3 Prepare lsquoEvent Nodesrsquo at the completion of steps and number them

4 Write the description of the step and decide the time required for completing each

step

5 Calculate the earliest time to reach an event node for the start of the process

7 Ager the time for all event nodes including the completion of the process or the

project is available one calculates the latest time by which an event node must be

reached

Application

The diagram is also useful in planning and scheduling steps in complicated processes

especially in planning and scheduling projects which involve a large number of

activities

Example

31

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 32: old and new  7 quality control tool

1 Identify the tasks Eg 123hellip15

2 Know the time each task needs

3 Determine which tasks can be run in parallel and in normal sequences

4 Draw the sequence diagram and find the critical path

5 Calculate the project duration

6 Calculate the earliest starting time (or the earliest finishing time of last task) and the

latest finishing time

of each task(the latest starting time for the following task)

7 Mark the time indication

32

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 33: old and new  7 quality control tool

33

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 34: old and new  7 quality control tool

4) Process Decision Program Chart (PDPC)

Def The process decision program chart (PDPC) method helps us select the best

processes to obtain optimum results by evaluating the progress of events and various

conceivable outcomes

Description

The process decision program chart (PDPC) method is used to define the solution

process when dealing with problems that have more than one possible outcome [t

anticipates the unexpected Outcomes at each stage and plans for it

PDPC has two following patterns

Pattern I ndash In this pattern process starts with initial condition lsquoArsquo and proceeds to the

desired final condition lsquoZrsquo in an organized manner

Pattern 11- In this pattern first the final conditionrsquosrsquo is set Then the process from lsquoZrsquo

to the initial point lsquoArsquo is developed with the inclusion of various alternatives from

many points of view

Procedure

Discuss the issues related to the project among a cross-functional team

Discuss which issues must be examined and identify those issues

Consider and note down all the anticipated results for the identified issues

Weigh the feasibility of each solution proposed and investigate alternate

solutions

Classify each issue according to its urgency number of operations required

likelihood of Occurrence and difficulty

Consider the anticipated results and alternative solutions related to issues that

must be addressed immediately and link the items with arrows to the desired

goal

34

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 35: old and new  7 quality control tool

Prioritize the different issues and consider them all together Information

related to one set of

Possibilities could influence another set Related items shall be linked with a

broken line

If the department that will handle a process involving several lines is

determined circle

the process and write the name of the department within

Set a target date for completion

Have regular meetings to check progress in terms of the original PDPC

35

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 36: old and new  7 quality control tool

36

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 37: old and new  7 quality control tool

37

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 38: old and new  7 quality control tool

38

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 39: old and new  7 quality control tool

5) Matrix diagram

Purpose1) Explore the existence and the extent of relations between individual items in 2 sets

of factors or features and characteristics and express them in a symbolic form that is

easy to understand

2) Mostly used to understand the relations between the customer expectations as

expressed by the customers and product characteristics as designed manufactured and

tested by the manufacturer

Procedures1 Determine 2 sets of factors for which the relations are needed to be established

2 Divide the features and characteristics into primary secondary and tertiary

characteristics

3 Place the features vertically on the leg side of the matrix and characteristics

horizontally on top of the matrix

4 Enter the importance of the features on the column ager that for the tertiary

features10485775 In the main body of the matrix use the symbols to represent the degree of

connections between the feature and characteristics

6 Choose and define relationship symbols Most commonly used symbols are as

given below

Strong relationship=

Relationship =

Likely relationship=

Application

bull Matrix diagram can be used to solve problems by arranging data in such a way that

the relations between relevant factors are brought into sharp focus

bull There is no limit to the use of the tool

39

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 40: old and new  7 quality control tool

bull The most important application of matrix diagram is in clarifying relations between

individual features of customer requirements and individual product characteristics

Example 1

Matrix Diagram for Quality Functions and Responsibilities

40

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 41: old and new  7 quality control tool

41

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 42: old and new  7 quality control tool

6) Matrix Data Analysis Diagram1048577

Purpose

To present numerical data about two sets of factors in a matrix form and

analyze it to get numerical output

Can be applied in understanding the products and products characteristics

Procedure1048577

1 Decide the two factors whose relations are to be analyzed

2 Check the number of individual items in the two factors

3 Prepare a matrix to accommodate all the items of the two factors

4 Enter numerical data in the matrix

5 Give the diagram a suitable title

Example

42

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 43: old and new  7 quality control tool

43

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 44: old and new  7 quality control tool

44

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 45: old and new  7 quality control tool

7) Relationship diagram

This diagram clarifies the interrelations in a complex situation involving many

interrelated factors and serves to clarify the cause and effect relationships among

factors

Description

Relations diagram is defined as a technique used to solve problems that have complex

cause and effect relationships among a number of problems and factors that influence

them

Format

A special feature of relation diagram is its unrestricted Format However general

formats are as given below

1) Centrally converging relations diagram

The major item or problem to be solved is located in the center and the related factors

are arranged around the item or problem in such a way as to indicate close

relationships

2) Directionally intensive relations diagram

The major item or problem to be solved is located on one side of the diagram and the

various factors arranged in accordance with the flow of their major cause-and-effect

relationships on the other side

3) Relationship indication relations diagram

There are no restrictions on this format because the main point is to arrange the cause-

and-effect Relationships of the application items or factors so that they are expressed

in a straightforward manner in a Diagram

45

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 46: old and new  7 quality control tool

Procedure

1) Define the issueproblem in such a way that it is clearly understood and agreed on

by team members

2) Assemble the cross-functional team

3) Layout all the ideasissue cards that have been brought from other tools

4) Look for causeinfluence relationships between all ideas and draw relationship

arrows

a) Choose any of the ideas as a starting point and work through them in sequence

b)An outgoing arrow from an idea indicates that it is the stronger cause or influence

c) Draw only one way relationship arrows in the direction of the stronger cause or

Influence Make a decision on the stronger direction Do not draw two headed arrows

5) Review and revise the relationsrsquo diagram

6) Tally the number of outgoing and incoming arrows and select key items for further

planning

-record and clearly mark next to each issue the number of arrows going in and out of

it

-find the items with the highest number outgoing arrows and the items with the

highest number of incoming arrows

-a high number of outgoing arrows indicate that the item is a root cause and should be

tackle first

46

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 47: old and new  7 quality control tool

-a high number of incoming arrows indicate that the item is a key outcome and may

become a focus for planning either as a meaningful measure of overall success or as a

redefinition of the original issue under discussion

Example

47

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 48: old and new  7 quality control tool

48

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 49: old and new  7 quality control tool

Conclusions

Statististical QC is chiefly concerned in making sure that several procedures

and working arrangements are in place to provide for effective and efficient

statistical processes to minimize the risk of errors or weaknesses in

procedures or systems or in source material

Seven QC tools are most helpful in troubleshooting issues related to quality

All processes are affected by multiple factors and therefore statistical QC tools

can be applied to any process

The continuous use of these tools upgrades the personnel characteristics of the

people involved It enhances their ability to think generate ideas solve

problem and do proper planning

49

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing
Page 50: old and new  7 quality control tool

References asqorglearn-about-qualityseven-basic-quality-toolsoverviewhtml

httpsenwikipediaorgwikiSeven_Basic_Tools_of_Quality

wwwijergsorgfilesdocumentsAPPLICATION-45pd

httpssrcalionsciencecompdfQualityToolspdf

www3haorghkqehwiserdoc7bqtpdf

wwwmathmunca~variyathNew7QCToolspd

50

  • 1 DEFINITION of Quality Control
  • 3 Competitiveness
  • 4 Customer Loyalty
  • 5 Reputation
  • 6 Compliance
  • 7 Costs
  • Benefits of Using Quality Control in Manufacturing