welcome to the training programme on quality circles 7 qc...

Business Excellence Divn, TRF Ltd.

Welcome to the Training Programme

on

Quality Circles&

7 QC TOOLS1TRF Limited


QC - Team

TRF Limited 2

Team size - 3 to 8 – preferebly 6 (including the facilitator)

Composition:Facilitator – 1no. - Can be any person Gradeless / Graded.

He / she can be facilitator of more than one QC.Leader – 1no. – Only Graded employeeHe / she can be a leader of only one QC

Members – Only Graded employeesCan be members of only one QC

The teams have to registered with the Business Excellence Divn. The QC facilitator will assign a serial no. to the Circle.


QC - Roles

TRF Limited 3

Facilitator –• To help the team with knowledge of job, data

analysis, suggestions on approach to be taken and be the mentor of the team

• To help the team in taking the step-by-step structured approach of QC

• To ensure regular functioning of the team

Leader -• To lead the team in taking up projects• To assign responsibilities to team members • To ensure regular functioning of the team• To ensure timely completion of projects• To prepare the document with the help of members

for project closure


QC - Functioning

TRF Limited 4

Meeting –• Should meet at least once in a week. Preferably on a

fixed day and time.• Team should maintain a register and record attendence

by having every members signature. It should write briefly the proceedings of the meeting

• Team should keep all its back-up records, sketches, drawings etc with the register


Project selection

TRF Limited 5

• The team should discuss various problems faced at their place of work, and prepare a list of these problems.

• The problems should relate to the objectives of their department – safety, cost reduction, reducing delays, improving quality, improving the method o working etc

• The team should priortize the problem based on criteria assigned by them. They can adopt the NGT (Nominal Group Technique)


Project selection – NGT Voting & Ranking

TRF Limited 6

Problem Mr A Mr B Mr C Mr D Total

Problem 1 4 3 3 5 15

Problem 2 1 1 4 2 8

Problem 3 7 5 6 7 25

Problem 4 2 2 1 3 8

Problem 5 5 6 2 1 14

Problem 6 3 4 5 4 16

Problem 7 6 7 7 6 26

Round - 1

Business Excellence Divn, TRF Ltd.TRF Limited 7

Problem Mr A Mr B Mr C Mr D Total

Problem 2 1 1 2 1 5

Problem 4 2 2 1 2 7

Round - 2

Project selection – NGT Voting & Ranking

SEVEN BASIC QUALITY TOOLS

Cause and Effect Diagram

Check Sheet

Histogram

Pareto Diagram

Stratification

Scatter Diagram

Control Chart8Business Excellence Divn. TRF Ltd.

Analysing a problem when the cause is not obvious

9Business Excellence Divn. TRF Ltd.

Cause & Effect Diagram

Or

Fish Bone Diagram

Cause & Effect Diagram: An Introduction

Invented by Prof. Kaoru Ishikawa in 1943. He first used toexplain at kawasaki Steel Works “How a complex set of factorscould affect the Problem”

Designed for:

Stimulating thinking during a brainstorm of potential causes

Providing a structure to understand the relationships between

many possible causes of a problem

Serving as a visual display of causes that have been studied

• Write only the characteristic and the causal factors which are measurable.

• After completing a cause & effect diagram, it is necessary to grasp the strength of the cause &effect relationship objectively using data

Graphical Technique that can be used in teams to identify and arrange all the possible causes of an event or problem or outcome

Effect: The kid fell…

Cause: Because of the water.

Special notes:

• Make the same number of cause & effect diagram as that of

characteristics.

• Error in weight and length of the same product will have

different cause & effect structures and these should be

analyzed in two separate diagrams

TRF Limited

Uses of The Cause and Effect Diagram

Sorts and segregates the possible causes of a problem

into a logical order

Identifies areas for data gathering activity

Educates participants in problem solving process

Serves as a guide for discussions and serves to keep

meetings on target

Can be developed into a complete project management

tool that displays actions taken and results achieved

11Business Excellence Dept.

Construction of a Cause and Effect Diagram

1. Define the characteristic to improve and control

Should be able to be quantified and measured

Quality characteristics = effect

2. Write the characteristic on the right side of the diagram

3. Draw a broad arrow pointing at the characteristic from the

left side of the diagram

Slow

Check - In

Effect12Business Excellence Dept.


4. Define the main factors which influence the characteristic to be improved

Factors = causes

Suggested main causal factors are as shown

5. Draw an arrow from each factor to the main central arrow

Slow

Check - In

Effect

EnvironmentMethodsPeople

Materials Machines

Causes



6. Determine the detailed causes for each of the main factors and draw an

arrow to the appropriate branch

On to each of these, write in even more detailed causes and draw

smaller arrows.

5. Continue in this manner to examine and display all potential causes

Slow

Check - In

Effect

EnvironmentMethodsPeople

Materials Machines

Causes

Front Desk Computer

Maintenance

Capability


Causes and Effect Diagram

Environment People Methods

Materials Machines

Slow

check - in

CAUSES EFFECT

Volume

Tempreture

A/C

Co

nte

nt

Ed

uc

ati

on

Training

Ac

cu

rac

y

Adequacy

Co

mp

lete

ne

ss

Consistency

Ve

nd

ors

Front Desk ComputerC

ap

ab

ilit

y Maintenance

Age

Self checks

Pre

cis

ion


Lack of welding methods/knowledge

Supver,thinks

person is

qualified

but not certified

Nobody in office

knows or asks

Always done it

Don’t know

Haven’t doc

No training

Once one

passes

all qualified

OG doesn’t

check

No

t c

ert

ifie

d

No trainers

Traiing

On cust material

Po

or trg

. No set process

Weld symbols

Don’t return cold red

Procedures 77

don’t have right quantity

Keep people busy

Weld Rod

Ta

ke

ou

t o

f h

ea

t

co

ntr

ol

too

ea

rly

Wrong order

quantity

Rush job

Av

ail

ab

ilit

y

Do

n’t

kn

ow

go

od

we

ld r

od

Bad attitude

Do

n’t c

are

No

prid

e

Pe

rso

na

lity

No

rew

ard

&

rec

og

nitio

n

La

ck

of

ex

pe

rien

ce

No

pro

ce

du

re

Hire

ine

xp

erie

nc

ed

pe

op

le

Mis

ca

lc.

Poor Judgement

Build experimental jobs

Lack of training

No

pro

ce

du

re

Ta

ke

too

mu

ch

time

No

foc

us

Some equipment

without gauges

Poor verbal communication

Poorly trained

Not available

Supervison

Do

n;t

se

e w

eld

pro

c

Ch

ec

k l

ist

Mis

sin

g i

nfo

on

we

ld p

roc

Amp

8300,00

P.M

fo

r A

MP

Re

co

nd

itio

n

No date

Av

ail

ab

ilit

y

Think we

save dollars

Dirty material

Ha

nd

lin

g

Ma

ch

ine

s l

ea

k

Old

Poor

maintenance Cra

ne

s l

ea

k

Park

maint.

enance

Ro

ols

le

ak

Don’t care

Not told

Old

Poor

maint-

enancePe

op

le w

alk

on

No

place

forit

Bad Prep

Wro

ng

Be

ve

l Operator

Train on procedure

Shear

Bu

rr

Bad adjustment

Bad blade

Burning Sla

g

Tempreture

Wrong tie

De

cis

ion

to

sto

p o

ve

rrule

d

Push work out

Disagreement on spec.Bad

fillings

Ba

d f

orm

ing

C.S.M

Too loose

Too tight

Doesn’t know

No

tim

ing

s

Siz

e

wro

ng

Wro

ng

le

ng

th c

ut

Not checked

Information wrong

on customer req.

(Cust. order)

Template shrinks

Std. size cone

template

Blueprint

worng

Being

rushed

Not

rained

Different

training

Do

n’t

se

e b

lue

pri

nt

?

PeopleTechniques

Bad

Welds

Vendor

Quality Internal

Supplier

Quality

CAUSE AND EFFECT DIAGRAM


Collecting data in a sytematic way


Check Sheet

Check Sheet: Introduction

Based on the purpose, customized check sheets are

designed

What is Check sheet used for?

• Controlling and monitoring the production process

• Analysis of cause and effect properly

• Inspection for non-conformance

• To make data-gathering easy

• To arrange data automatically so that they can be used easily later on

What is it?

• A tool for collecting data in a consistent form.

• Provides an easy, structured way of

recording data as it is collected

• Assures data will be recorded in similar manner

TRF Limited

Check Sheet: An Example

Monitoring Number of defects in a Day Total

Shift A Shift B Shift C

CHATTER //// //// //// //// //// /// //// / 33

SPM ROLL MARKS //// / //// // 12

SPM PINCH MARKS //// //// //// // // 18

SPM SCRATCHES // /// 5

SPM DENTS // //// /// 10

RUBBING MARK - SPM //// 5

BLACK SPOTS NON REMOVABLE

// / 3

Total 38 37 11 86

Number inspected 2037 Percentage defects 4.3%

Product name Lot number Date

Process name

Measuring method

Measuring instrument

Recorded by:

Decide the purpose: In the example check sheet is being used for inspectionDesign the Format: Based on the requirement, the fields are customized

TRF Limited

Analyzing data


Histogram, Pareto Diagram, Stratification,

Scatter Diagram

Purpose:

Visual depiction of data, helps to infer about the population at a glance

Histogram: An Introduction

Benefits:

• The shape of the histogram shows process behavior

• The shape and size of the dispersion helps identify otherwise hidden sources of variation

• Presence of multi-modes may give a hint about mixed processes

• Used to determine the capability of a process

• Starting point for the improvement process

• Plots the number of times an event has occurred within a range of value.

• Shows the distribution of occurrence of event

10 11 12 13 14 15 16 17 18 19

0

5

10

Time Estimates (in seconds)

# o

f O

ccu

rren

ces

TRF Limited

Normal distribution Skewed distributionThe ideal case, if a point has a chance to assume any value around a target( in absence of special cause variation ) it will take this shape. Most unlikely to exist in reality.

• May be because the specification limit is in only on one side or process is controlled on one side

• Value lower than a certain value does not occur. Most commonly found

• May be because beyond some point the output is considered as defect.

Skewed distribution, no tail on one side

Histogram: Types & Information Provided

Multiple processes Comb shaped• Existence of more than one process, Can lead to wrong conclusion needs to be stratified

• May be because of a particular tendency in the way data is rounded off.

TRF Limited

Pareto Diagram: An Introduction

What It is?

Developed by Vilfredo Pareto (1897), anItalian economist

He observed that 80 % of Italy’s wealth layin the hands of 20 % of the population

Used for prioritization by 80-20 rule.

Differentiates ‘Vital Few’ from ‘UsefulMany’ (Juran)

Left vertical axis depicts the actualfrequency of items while the right verticalaxis denotes cumulative percentage

Vital few

Useful Many

Benefits:• Useful in establishing priorities

• Comparing Pareto charts of a given situation over time determines whether an implemented solution reduced the relative frequency or cost of that problem or cause

TRF Limited

Comparison of Pareto Diagrams Before and After Improvement

Comparing Pareto Charts

While comparing Pareto Charts, the left vertical axis should have the same scaling

TRF Limited

Scatter Diagram: An Introduction

A graphical representation of relationship between twovariables. It can be between a cause and effect or betweentwo causes. The better the correlation, the tighter thepoints will hug the line

Provides both a visual and statistical means to test the strength of relationship between two variables

When to use scatter diagram:

• Once the causal relationship between the two variables is

established through cause and effect diagrams

Scatter Diagram Consideration:

• Scatter Diagram is used only when both, dependent & independent variables are continuous

• Scatter diagram should be jointly used with correlation coefficient, the value of correlation

coefficient (depicted by r) varies from -1 to +1.

• Correlation implies a linear relationship between two variables. For non-linear relationships r

may not give value close to 1 or – 1 even if the relationship is evident

• Extrapolation of the strength of relationshipbeyond given range of data is risky.

Correlation Coefficientr = 0.702

Characteristic

Ch

ara

cte

rist

ic

• It is desirable to have at least 30 pairs of data

• Decide the horizontal & vertical scales so that the finished

diagram is approximately square

Best Fit Line

TRF Limited

Scatter Diagram: Some Examples

(f) Need Stratification

(a) Strong Positive Correlation

n ＝５０

(d) Negative Correlation

(b) No Correlation (C) Positive Correlation

×××××××××××××××××××××××

××××××××××××××

×××××××

×××

×

×

××××××××××××××××××

×

×××

××××××××××

×× ××××

×××××

××××

×

×××××××

×××

×××××××××

××××

×

×××××

×××××××××

××××× ××

×××××

×

×××× × ××××

××× ××××× ××××

×

× ×××

×××

××××××××××

×××××××

×× ×

×× ××

××××

××××××××××××

×××× ×

×××××××

×

×××××××

× ××

×××

×

×

××

×××××××

×× ×××××× ××

×××

×××××

××

n ＝５０ n ＝５０

n ＝５０n ＝５０n ＝５０ ××××××

××××××××

×××××××××××××××××××××

×××××××

×××

(e) Strong Negative Correlation

Example from “ Statistical Methods for Quality Improvement” by Hitoshi Kume

Look for the outlying points, points far from main group are assumed to be the result of

errors in measurement. It is necessary to exclude such data for correlation.

r ≈ 0.913 r ≈ 0.001 r ≈ 0.725

r ≈ -0.925r ≈ -0.617

TRF Limited

Stratification: An Introduction

When the observed values represent two or more sub-populations according to the conditions which existed atthe time of data collection, such sub populations arecalled strata, and dividing data into strata is calledstratification.

When data from a variety of sources or categories have been lumped together, it becomes impossible to conclude meaning. Stratification is a technique that separates

the data so that patterns can be seen.

Number of rejections stratified basedon Supplier (A&B), Operator (1,2,3,4)

When to use stratification:

• When data comes from several sources or conditions

• When data analysis may require separating different sources or

conditions for detailed study of the problem.

Stratification Consideration:• Examples of different sources that might require data to be stratified:

By time: month, week, day, shift etc. By work force: operator, section etc By Machinery and

Equipment, BY Raw Materials: Supplier, previous process, lot, place of manufacture etc. By

Product: Product category, destination, special order etc., ByMeasurement / Inspection.

• Always consider before collecting the data whether stratification might be needed during analysis.

Plan to collect stratification information. After the data is collected it might be too late.

4753

27 24 23 26

0

10

20

30

40

50

60

Sup A Sup B Op 1 Op 2 Op 3 Op 4

No

. of

reje

ctio

ns

TRF Limited

28

Histogram (A+B)

82.0 82.5 83.0 83.5 84.0 84.5 85.0 85.5 86.0 86.5 87.0 87.5 88.0 88.5

Yield

0

2

4

6

8

10

12

14

16

18No

of ob

serva

tions

Two vessels, A and BHistogram (B)

82.5 83.0 83.5 84.0 84.5 85.0 85.5 86.0 86.5 87.0 87.5 88.0 88.5

Yield

0

2

4

6

8

10

12

14

No

of

ob

serv

ati

on

s

Histogram (A)

82.0 82.5 83.0 83.5 84.0 84.5 85.0 85.5 86.0 86.5 87.0

Yield

0

2

4

6

8

10

12

14

16

18

No of observations

Average 86.03

Stdev 1.036

Max 87.9

Min 83

Average 84.07

Stdev 0.805

Max 86.3

Min 82.7

A BNow it is telling a different story.

Vessel A and vessel B are behaving differently, therefore to be dealt with differently.

After Stratification :

Stratification: An Example

No. of data points = 100

Mean =85.05

Stdev = 1.35

Max : 87.9

Min : 82.7

Combined data from a chemical reaction process in two vessels, A and B

TRF Limited

Understanding the current problem.

Monitoring Improvements


Graphs, Run Charts, Control Charts

RUN CHARTM

easu

rem

ent

Time

Average


RUN CHART BENEFITS

Simplest display of trends over time

Data plotted in time order

An aid to understanding basic characteristics of a process


Run Chart ExampleCustomer Inquiries

109876543210

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Nu

mb

er o

f In

qu

irie

s

Week


Measu

rem

en

t

Control Chart

Time

Upper Control Limit

Lower Control Limit

Average


CONTROL CHART BENEFITS

Displays the expected range of variation in a stableprocess

Display relative stability of a process

Assists in process analysis. Can indicate whensomething out-of-the-ordinary happens

Assesses effects of process control and processimprovement


Me

asu

re

Process In Control

UCL

x

LCL

Time


Me

asu

re

Process In Control

UCL

x

LCL

Time

Out of Control


Interpreting Control Charts

Chart

ProcessIn

Control

ProcessOut of

Control

Run

Chart points donot form a parti-cular pattern andlie within theupper and lowerchart limits

Chart points form a particular pattern OR oneor more pointslie beyond theuppor or lowerchart limits

Chart points areon one side of thecenter line. The number of pointsin a run is calledthe “length of therun”

UCL 10

x 19

lcl 30

UCL 10

x 19

lcl 30

UCL 10

x 19

lcl 30

UCL 10

x 19

lcl 30

UCL 10

x 19

lcl 30

UCL 10

x 19

lcl 30

The process is stable, notchanging. Doesn’t necesarily mean to leavethe process alone. Maybe opportunities to improvethe process and enjoy substantial benefits

Alerts us that the processis changing. Doesn’t mean you need to take a corrective action. May berelate to a change you havemade. Be sureto identifythe reason\(s) before takingany constructive actions(w)

Suggest the process hasundergone a permanentchange (positive ornegative) and is nowbecoming stable. Often requires tha t you recompute the controllines for future interpre-tation efforts.

Description Example # 1 Example # 2 Interpretation


Interpreting Control Charts

Chart

Trend

Cycle

Hugging

A continued riseor fall in a seriesof points (7 ormore consecutivepoints direction)

Chart ponts showthe same patternchanges (e.g.riseor fall) over equalperiods of time

Chart points areclose to the centerline or to a control limit line(2 out of 3, 3 out of4, or 4 out of 10.)

UCL 10

x 19

lcl 30

UCL 10

x 19

lcl 30

UCL 10

x 19

lcl 30

UCL 10

x 19

lcl 30

UCL 10

x 19

lcl 30

CL 10

x 19

lcl 30

Description Example # 1 Example # 2 Interpretation

12

34

5 6 7

1/2

1/2

12

3

4

56

1/2

1/2

Often seen after some changehas been made. Helps tellyou if the change(s) had apositive or negative effect.may also be part of a learning curve associatedwith some form of training

often relates to factors thatinfluence the process in apredictable manner. Factorsoccur over a set time periodand a positive/negative effectHelps determine future workload and staffing levels

Suggests a different type ofdata has been mixed into thesub-group being sampled.Often need to change thesub-group, reassemble thedata, redraw the controlchart


Thank you!

TRF Limited

welcome to the training programme on quality circles 7 qc...

Documents