4 tqm_quality tools and techniques

8/2/2019 4 TQM_Quality Tools and Techniques

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Total Quality Management


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Quality Tools and Techniques


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Tools of TQM

Flow Chart Cause-and-Effect

Run (Trend) Chart

TimeMeasure

Control Chart

Measurement Time

X

UCL

LCL

Xbar

Scatter Diagram

Variable 1Variable

2

Pareto Chart

X

Type

Histogram

Measurement

X


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Flow Charts

How a process works and what is it supposed to do

Common understanding for all involved

Best developed by having people involved in theprocess construct it

Can be used to identify quality problems andproductivity improvement


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Symbols in a Flow Chart

Start or Stop

Direction of flow

Single step

Decision point

Connection


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Flow chart: From bed to work

Sleep late

Yes

NoAlarm rings

Start coffee

Bathroomavailable

Yes

No Wait

Shower

Clothesready

Yes

No Iron clothes

Get dressed

Eat breakfast

Read Paper

Car

Available

Park in lot

Yes

Drive to work

Yes

No

No

No

Watch TV

Take Bus

Park & Walk

Sunrise

Arrive at work

Trigger

Target

Start or Stop

Direction of flow

Single step

Decision point

Connection


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Flow Chart

From College to Home


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Pareto Analysis

Purpose: To identify and highlight major symptomsof major quality problems

Based on the premise that usually, a small numberof faults cause the majority of malfunctions

To separate the vital few and trivial many


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Pareto Analysis

B

Frequency

A C D F

....

E

3

2

1

8

12


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Developing Pareto Analysis Define the classification of defects to be monitored

Define the period of time over which the assessment is to be

made Total the frequency of occurrence of each class of defects over

the period, and calculate the percentages of frequencies

Plot the histogram of the classes in descending order of the

frequency of occurrence, and then identify the classes thatconstitute the majority of defect occurrences


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Percentfr

ome

achcause

Causes of poor quality

0

10

20

30

40

50

60

70(64)

(13)(10)

(6)(3) (2) (2)


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Problem: The manager of a neighborhood restaurantis concerned about the smallest numbers of

customers patronizing his eatery. He surveyed hiscustomers over several weeks and collected thefollowing data:


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Run Charts ( Trend Charts)

Continuous activity requiring measurements to bemade periodically over time

A line graph in which data are plotted over time

Can be used to track performance and process

variations

Summarize data in a graphical format

Time

Measurem

ent


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Run Chart: Getting to work on time

M M M MT T T T T T T TW W W WF F F F

Week 1 Week 2 Week 3 Week 4

15

20

25

30

35

Minutesto

work


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Histogram

Graphically displays quantitative data

Provides information about process and activityperformance

Helps in identifying process capability related to

customer requirements

Graphic pictures that quickly summarize variations


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Histogram

Frequency

Data Ranges

....


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Histogram: Test Scores

Test scores for 20 students

48, 49, 50, 46, 47, 47, 35, 38, 40, 42, 45, 47, 48, 44, 43,46, 45, 42, 43, 47. Use 5 classes


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Scatter Diagram

Used to study possible relationships between twovariables

Purpose is to display what happens to one variablewhen another variable is changed

Used to test a theory that the two variables arerelated

Type of relationship that exits is indicated by theslope of the diagram


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Scatter Diagram: Drive Time

0

5

10

15

20

25

30

35

40

45

50

7:00 7:30 8:00 8:30 9:00

Time Leaving House

T

ravelTimetoW

ork(minutes)


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Scatter Diagram: Time spent onstudies-Marks scored


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Tools of TQM

Flow Chart Cause-and-Effect

Run (Trend) ChartTime

Measure

Control Chart

Measurement Time

X

UCL

LCL

Xbar

Scatter Diagram

Variable 1Variable

2

Pareto Chart

X

Type

Histogram

Measurement

X


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Assignment

1. Construct a u-chart for the following data and comment on

the process.

Sample No. No. of Defects Sample Size

1 8 92

2 15 69

3 6 86

4 13 855 5 123

6 5 87

7 3 74

8 8 83

9 4 10310 6 60

2. Construct a flow chart for Filling petrol in car taking your

own assumptions, and using all the symbols. The triggerpoint should be Low petrol warning by car and the target

should be Tank is full.

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