7 QC Tools.ppt

7/23/2019 7 QC Tools.ppt

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PROBLEM SOLVING

Quality Improvement: Problem Solving

Quality Tools






Quality management activities

Quality assurance Establish organisational procedures and standards for quality.

Quality planning Select applicable procedures and standards for a particular project

and modify these as required.Quality control Ensure that procedures and standards are followed by the software

development team.

Quality management should be separate from project

management to ensure independence.



Six Problem Solving Steps

Identify recognie the symptoms

Define !gree on the problem and set boundaries

Investigate "ollect data

Analyze #se quality tools to aid

Solve $evelop the solution and implement

Confir %ollow up to ensure that the solution is effective



Quality "ontrol Tools


Pareto chart

&istogram

Process flow diagram

"hec' sheet

Scatter diagram "ontrol chart

(un chart

"ause and effect diagram



Pareto Principle


)ilfredo Pareto *+,-,+/012 3talian economist 045 of the population has ,45 of the wealth

6uran used the term 7vital few8 trivial many9. &e

noted that 045 of the quality problems caused ,45of the dollar loss.

7 Quality Tools7 Quality Tools



Pareto "hartsP!r"ose#Prioritie problems.

$o% is it done&"reate a preliminary list ofproblem classifications.

Tally the occurrences in each

problem classification. !rrange each classification

in order from highest tolowest

"onstruct the bar chart



Pareto "harts

Benefits:Benefits: Pareto analysisPareto analysis

helpshelps

graphicallygraphically

display resultsdisplay resultsso theso the

significant fewsignificant few

problemsproblems

emerge fromemerge fromthe generalthe general

backgroundbackground

It tells you whatIt tells you what

to work on firstto work on first



Pareto chart



% Complaints



Pareto

"hart


P e r c e n t f r o m e

a c h c a u s e

Causes of poor quality

M a c h i n e

c a l i b

r a t i o

n s

D e f e c

t i v e p

a r t s

W r o n g

d i m e

n s i o n

s

P o o r

D e s i g n

O p e r a t o

r e r r o

r s

D e f e c

t i v e m

a t e r i a l s

S u r f a

c e a b r a s i o

n s0

10

0

!0

"0

#0

$0

%0

&$"'

&1!'&10'

&$'&!' &' &'



(istograms

What is it)* + (istogram is a bar graph

* usually used to present frequency data

(o, does it Wor-)* Define Categories for Data

* Collect Data. sort them into the categories

* Count the Data for each category

* Dra, the Diagram/ each category finds its place on the +is/

* 2he bars ,ill be as high as the value for the category

What is its use)* (istograms provide an easy ,ay to evaluate the distribution of

Data over different categories

LSL SL


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(istograms

LSL SL

"#ample:

take the failure rate of a machine

over a period of # weeks$ %ow

&ssign every week the number of

failures that occurred$ 'raw the(istogram$ Let the bar represent the

weeks$ )he height of the Bar on the

y*a#is is the number of failures that

occurred during that week$



%low $iagrams


: $raw a flowchart for whatever you do. #ntil youdo8 you do not 'now what you are doing8 you justhave a job.9

$r. ;. Edwards $eming.



%lowcharts


%lowcharts <raphical description of how wor' is done.

#sed to describe processes that are to be improved.




%low "hartsP!r"ose#

)isual illustration of the sequence of operations requiredto complete a tas'

Schematic drawing of the process to measure or improve. Starting point for process improvement Potential wea'ness in the process are made visual. Picture of process as it should be.

Benefits#

3dentify process improvements #nderstand the process

Shows duplicated effort and other nonvalueadded steps "larify wor'ing relationships between people and

organiations Target specific steps in the process for improvement.



%low charts=inearBenefits

Show what actually happensat each step in the process

Show what happens whennonstandard events occur

<raphically display processes

to identify redundancies andother wasted effort

$o% is it done& ;rite the process step inside

each symbol

"onnect the Symbols witharrows showing the directionof flow

)oolbo#



%low $iagrams




%low $iagrams




Process "hart


S t e p

+ p e r a t i o n

) r a n s p o r t

I n s p e c t

' e l a y

S t o r a g e

' i s t a n c e

, f e e t -

) i m e

, m i n -'escription

of

process

1

!

.

/

0

2

3

4

15

11

nload apples from truck

6ove to inspection station

7eigh8 inspect8 sort

6ove to storage

7ait until needed

6ove to peeler

&pples peeled and cored

Soak in water until needed

Place in conveyor

6ove to mi#ing area

7eigh8 inspect8 sort

)otalPage 1 5f . /35

.5

0

!5

10

.5

.5

!5

145 ft

!5 ft

!5 ft

05 ft

155 ft

'ate: 4*.5*55

&nalyst: )L9

Location: raves 6ountain

Process: &pple Sauce






"hec' Sheet


√

√

√ √

√

√

√ √ √

√

√

√ √ √ √ √

√ √ √

√ √ √

ShiftsShifts

D

e f e c t 2 y p e

D

e f e c t 2 y p e


√ √ √ √



"hec'sheetsP!r"ose#

Tool for collecting andorganiing measured orcounted data

$ata collected can be used asinput data for other qualitytools

Benefits#"ollect data in a systematic and

organied manner

To determine source of problemTo facilitate classification of

data *stratification2



"hec' Sheet


COMPO3432S 54P6+C4D 78 6+7

29M4 P459OD: ;eb to % ;eb 1<<=

54P+95 24C(39C9+3: 7ob

2> S42 MOD46 101!

9ntegrated Circuits ;;;;

Capacitors ;;;; ;;;; ;;;; ;;;; ;;;; ;;

5esistors ;;2ransformers ;;;;

Commands

C52 ;



"auseandEffect $iagrams


Show the relationships between a problem and itspossible causes.

$eveloped by >aoru 3shi'awa *+/?12

!lso 'nown as @ %ishbone diagrams

3shi'awa diagrams




"ause and Effect 7S'eleton9


Quality

Problem

6aterials

"<uipmentPeople

Procedures




%ishbone $iagramPurpose:Purpose: raphicalraphical

representation of the trailrepresentation of the trailleading to the root cause of aleading to the root cause of a

problemproblem

(ow is it done=(ow is it done=

* 'ecide which <uality'ecide which <ualitycharacteristic8 outcome orcharacteristic8 outcome or

effect you want to e#amineeffect you want to e#amine

,may use Pareto chart-,may use Pareto chart-

* Backbone >draw straightBackbone >draw straight

lineline

* 9ibs > categories9ibs > categories

* 6edium si?e bones >6edium si?e bones >

secondary causessecondary causes

* Small bones > root causesSmall bones > root causes



"ause A Effect $iagrams

Benefits#Brea's problems down into bitesie pieces to find root

cause

%osters team wor'

"ommon understanding of factors causing the problem

(oad map to verify picture of the process

%ollows brainstorming relationship



%ishbone $iagram


?uality

Problem

MachinesMeasurement (uman

Process4nvironment Materials

;aulty testing equipment

9ncorrect specifications

9mproper methods

Poor supervision

6ac- of concentration

9nadequate training

Out of ad@ustment

2ooling problems

Old A ,orn

Defective from vendor

3ot to specifications

Materialhandling problems Deficienciesin product

design

9neffective quality

management

Poor process

design

9naccurate

temperature

control

Dust and

Dirt



@ause A "ffect 'iagramsSample

Incorrect

shipping

documents

6anpower 6aterials

6ethods 6achine

"nvironment eyboard

sticks

7rong source info

7rong purchaseorder

)yposSource info

incorrect

'ysle#ic)ransposition

'idnCt follow

proc$ P o o r t r a

i n i n g

lare on

display)emp$

%o

procedure%o communications

%o training

Software

problem

@orrupt

data



"ause and effect diagrams


!dvantages ma'ing the diagram is educational in itself

diagram demonstrates 'nowledge of problem solving team

diagram results in active searches for causes

diagram is a guide for data collection



"ause and effect diagrams


To construct the s'eleton8 rememberC

%or manufacturing the - Ds man8 method8 machine8 material

%or service applications equipment8 policies8 procedures8 people



Quality "ontrol Tool

@ontrol @harts



"ontrol "harts

P!r"ose#The primary purpose of a control chart is topredict expected product outcome.

Benefits# Predict process out of control and out of

specification limits

$istinguish between specific8 identifiablecauses of variation

"an be used for statistical process control



"ontrol "hartsStrategy for eliinating assigna'le()a!se variation# Get timely data so that you see the efect o the

assignable cause soon ater it occurs. As soon as you see something that indicates that an

assignable cause o variation has happened, searchor the cause.

Change tools to compensate or the assignable cause.Strategy for reducing common-cause variation: Do not attempt to explain the diference between any

o the values or data points produced by a stablesystem in control.

Reducing commoncause variation usually re!uiresma"ing undamental changes in your process



"ontrol "harts

Control C*art De)ision +ree

$etermine Sample sie *n2

)ariable or !ttribute $ata

)ariable is measured on a continuous scale

!ttribute is occurrences in n observations

$etermine if sample sie is constant or changing



1!D54D10 .2

Scatter Diagrams

What is it)* Statistical tool sho,ing a trend in a series of values/

(o, does it Wor-)* Bain values series

* Dra, graph ,ith value points

* Dra, trend line: maE Calculate m value

E Calculate a value

E Calculate points for trend line/

What is its use)* Demonstrating correlations bet,een values and sho,ing trends

for value changes/

E

F



Scatter DiagramsPurpose:

2o identify the correlations that might eistbet,een a quality characteristic and a factorthat might be driving it

* + scatter diagram sho,s the correlationbet,een t,o variables in a process/

F 2hese variables could be a Critical 2o

?uality &C2?' characteristic and a factoraffecting it t,o factors affecting a C2? ort,o related quality characteristics/

* Dots representing data points are scattered onthe diagram/

F 2he etent to ,hich the dots cluster togetherin a line across the diagram sho,s the

strength ,ith ,hich the t,o factors arerelated/



Scatter Diagrams* If the variables are correlated8

when one changes the other

probably also changes$

* 'ots that look like they are

trying to form a line are

strongly correlated$

* Sometimes the scatter plot

may show little correlation

when all the data areconsidered at once$

Stratifying the data8 that

is8 breaking it into two or

more groups based on

some difference such as

the e<uipment used8 thetime of day8 some

variation in materials or

differences in the people

involved8 may show

surprising results



Scatter Diagrams(ow is it done=:

* Decide ,hich paired factors you ,ant to eamine/ 7oth

factors must be measurable on some incremental linear

scale/

* Collect !0 to 100 paired data points/* ;ind the highest and lo,est value for both variables/

* Dra, the vertical &y' and horiGontal &' aes of a graph/

* Plot the data

* 2itle the diagram

The shape that the cluster of dots takes will tell you something

about the relationship between the two variables that you tested.



1!D54D10 /1

5un Charts

What is it)* 5un Charts are representing change

* in measurement over a sequence or time

(o, does it Wor-)* Bather Data

* OrganiGe DataE Measurements &y' must be confronted ,ith time or sequence of the

events/

* Chart Data

* 9nterpreting Data

What is its use)* Determining Cyclic 4vents and there average character

)ime

6 e a s u

r e m e n t



Control Charts

5un Charts

7hat does it look7hat does it look

like=like=o &dding the element of&dding the element of

time will help clarifytime will help clarify

your understanding ofyour understanding of

the causes of variationthe causes of variationin the processes$in the processes$

o & run chart is a line& run chart is a line

graph of data pointsgraph of data points

organi?ed in timeorgani?ed in timese<uence and centeredse<uence and centered

on the median dataon the median data

value$value$



1!D54D10 /.

5un Charts

4ample* Oil consumption of a specific machine over a period of time/

)ime

6 e a s u r e m

e n t



Control Charts

What is it)* Statistical tool. sho,ing ,hether

* + process is in control or not

(o, does it Wor-)* Define Hpper limit. lo,er limit and medium value

* Dra, Chart/

* Bather values and dra, them into chart

What is its use)* 2a-ing samples of a process and detect possibility of process being out

of control

E

F

pper limit

Lower limit

&verageDSpec

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7 QC Tools.ppt