5-1 collect & interpret data use spc to maintain current process collect & interpret data...

5-1

Collect & Interpret DataCollect & Interpret Data

Use SPC to Maintain Current Process

Collect & Interpret

Data

Collect & Interpret

Data

Select Measures

Define Process

IsProcessCapable

?

Improve Process

Capability

IsProcessStable

?

Investigate & Fix

Special Causes

No

Yes

No

Yes

Collect & Interpret Data: Diagnosing VariabilityPurpose:

Begin to understand why there is variability in data collected

TheQualityImprovementModel

5-2


What size shoe do you wear?

1 2 3 4 5 6 7 8 9 10 11 12

Size 11 Shoes

Why aren’t size 11’s all the same size?

5-3


GC CHDM Test Method Example

Why don’t we get the same %Water value?

Batch

% W

ate

r

75716763595551474339

0.50

0.45

0.40

0.35

0.30

Time Series Plot of % Water

% Water

Frequency

0.5000.4750.4500.4250.4000.3750.3500.325

14

12

10

8

6

4

2

0

Histogram of % Water

5-4


Cause & Effects MatrixCause & Effects Matrix

Rating of Importance to Customer 8 8 4 9 10 4 8 8

1 2 3 4 5 6 7 8

Plu

ggin

g C

ycle

Tim

eLe

ngth

D

istr

ibut

ion

Por

osity

D

istr

ibut

ion

Col

or

Cat

alys

t P

erfo

rman

ce

Mol

y D

istr

ibut

ion

in

Pel

lett

(w

ithin

&

bet

wee

n)

Dus

t/F

ines

C

onte

nt%

Mol

y &

%

Nic

kel

Total

Process Step Process Input

1 Mixing Total Rate 0 3 0 0 0 0 0 0 242 Mixing Mixer Speed 0 1 1 0 0 0 0 0 123 Mixing Al2O3 Quality 1 9 9 0 0 0 3 0 1404 Mixing Recycle Composition 1 1 1 0 0 3 0 9 1045 Mixing Recycle Rate 1 1 1 0 1 3 3 9 1386 Mixing Nitric Acid 0 9 9 0 0 0 0 0 1087 Mixing Water Temperature 0 1 1 0 0 0 0 0 128 Mixing Water Flow 0 9 9 0 0 0 0 0 1089 Mixing Recycle Water Rate 0 3 3 0 0 1 0 1 48

Cause & Effect Matrix – A Tool to Identify and Quantify Sources of Variation

5-5


Relates the key inputs to the key outputs (customer requirements) using the process map as the primary information source

Key outputs are scored as to importance to the customer

Key inputs are scored as to relationship to key outputs

Pareto of key inputs to evaluate in the FMEA and control plans

Input into the initial evaluation of the Process Control Plan

Cause and Effects Matrix

5-6


Identify key customer requirements (outputs) from process map or other sources

Rank order and assign priority factor to each Output (usually on a 1 to 10 scale)

Identify all process steps and materials (inputs) from the Process Map

Evaluate correlation of each input to each output low scorelow score: changes in the input variable (amount,

quality, etc.) have small effect on output variable high scorehigh score: changes in the input variable can greatly

affect the output variable Cross multiply correlation values with priority

factors and sum for each input

Cause & Effect Matrix Steps

5-7


Examples

Bottle Production Big Block Diagram

Bottle ProductionUpstream Inputs Outputs Downstream

Resin IV Regrind % Break % at Molder Break % at FillerOther resin Properties Barrell Temperature Bottle Output Etc…Bottle Design Screw Speed Melt TemperatureEtc… Screw Design Clarity

Etc… WeightWall Thickness VariationEtc…

Note: Only a partial list

5-8

Collect & Interpret DataCollect & Interpret DataBottle Production Example

Bottle Production Block Steps DiagramInputs Outputs

ResinVacuum out of

box Pellet change

Blending with Regrind

Dryer Hopper(Regrind + virgin)

Vacuum into machine hopper

ResinRegrind%-C

Barrel temperature-CScrew speed-C

Meter cooling temp-CScrew design-C

Barrel/screw condition-U

Melt ResinMelt Temperature

Melt strengthMW/IV

Throughput

Parison programming-CHead adapter design-C

Head design (PVC, HDPE)-CTooling

Zone tempsDie tip temp

Support air (straight and controlled)Parison cut

Extrude Parison

Parison lengthParison diameter

Parison tempThickness Profile

ClarityMelt stability

Note: Only a partial Map

5-9


Rating of Importance to

Customer

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Total


1 02 03 04 05 06 07 08 0

Excel Template C&E Matrix.XLSExcel Template C&E Matrix.XLS

1. List Key Outputs

Cause & Effect Matrix Form

5-10



Customer

1 2 3 4 5 6

Bre

ak %

Melt T

em

p

Bott

le O

utp

ut

Cla

rity

Weig

ht

Wall

Variation

Total


0000000000000

1. List Key

Outputs

The Outputs are defined in Step 1 of Process MappingThe Outputs are defined in Step 1 of Process Mapping

Bottle Production Example

5-11



Customer

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Total


1 02 03 04 05 06 07 08 0

2. Rank Outputs as to

Customer importance


5-12



Customer10 1 9 9 5 8

1 2 3 4 5 6

Bre

ak %

Melt T

em

p

Bott

le O

utp

ut

Cla

rity

Weig

ht

Wall

Variation

Total


2. Rank Outputs as to Customer importance


5-13



Customer

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Total


1 02 03 04 05 06 07 08 0

3. List Key Inputs by

Process Step


Note: Information obtained from process map

5-14




1 2 3 4 5 6

Bre

ak %

Mel

t T

emp

Bot

tle O

utpu

t

Cla

rity

Wei

ght

Wal

l Var

iatio

n


Melt Resin ResinMelt Resin Barrell TempMelt Resin Screw SpeedMelt Resin Screw DesignMelt Resin Regrind%

Melt ResinBarell/Screw Condition

Melt ResinScrew Tip Cooling

Extrude Parison ProgramingExtrude Parison Die Tip TempExtrude Parison Head DesignExtrude Parison Tooling Extrude Parison Support AirThis step uses the Process Map inputs directly. Notice the Process Inputs

follow the Process map step-by-step.

3. List Key Inputs by Process

Step


Note: Only a partial list of inputs

5-15



Customer

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Total


1 02 03 04 05 06 07 08 0

4. Relate Inputs to Outputs


5-16


You are ready to relate the customer requirements to the process input variables

Correlational scoresCorrelational scores: No more than 4 levels 0, 1, 3 and 9

Assignment of the scoring takes the most time To avoid this, spell out the criteria for each score:

00 = No correlation

11 = The process input only remotely affects the customer requirement

33 = The process input has a moderate effect on the customer requirement

99 = The process input has a direct and strong effect on the customer requirement

Relating Inputs to Customer Requirements

5-17




1 2 3 4 5 6

Bre

ak %

Melt T

em

p

Bott

le O

utp

ut

Cla

rity

Weig

ht

Wall

Variation

Total


1 Melt Resin Resin 9 9 3 9 9 9 3241 Melt Resin Barrell Temp 3 9 9 1 3 3 1681 Melt Resin Screw Speed 3 9 9 1 3 3 1681 Melt Resin Screw Design 3 9 9 1 1 1 1421 Melt Resin Regrind% 3 1 1 3 3 3 106

1 Melt ResinBarell/Screw Condition

3 3 3 1 1 1 82

1 Melt ResinScrew Tip Cooling

1 1 3 0 3 3 77

2 Extrude Parison Programing 3 3 9 0 9 9 2312 Extrude Parison Die Tip Temp 3 3 3 9 3 9 2282 Extrude Parison Head Design 3 9 3 3 3 9 1802 Extrude Parison Tooling 3 3 3 3 3 9 1742 Extrude Parison Support Air 1 0 9 0 1 1 104

2 Extrude ParisonLower Manifold

3 3 3 3 1 1 100

4. Relate Inputs to Outputs

This is a subjective estimate of how influential the key inputs are on the key outputs



5-18



Customer

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Req

uire

men

t

Total


1 02 03 04 05 06 07 08 0

Sum of (Rating x Correlation Score) values for all Requirements

5. Cross-multiply and

prioritize


5-19




1 2 3 4 5 6

Bre

ak %

Melt T

em

p

Bott

le O

utp

ut

Cla

rity

Weig

ht

Wall

Variation

Total


1 Melt Resin Resin 9 9 3 9 9 9 3241 Melt Resin Barrell Temp 3 9 9 1 3 3 1681 Melt Resin Screw Speed 3 9 9 1 3 3 1681 Melt Resin Screw Design 3 9 9 1 1 1 1421 Melt Resin Regrind% 3 1 1 3 3 3 106

1 Melt ResinBarell/Screw Condition

3 3 3 1 1 1 82

1 Melt ResinScrew Tip Cooling

1 1 3 0 3 3 77

2 Extrude Parison Programing 3 3 9 0 9 9 2312 Extrude Parison Die Tip Temp 3 3 3 9 3 9 2282 Extrude Parison Head Design 3 9 3 3 3 9 1802 Extrude Parison Tooling 3 3 3 3 3 9 1742 Extrude Parison Support Air 1 0 9 0 1 1 104

2 Extrude ParisonLower Manifold

3 3 3 3 1 1 100

5. Cross-multiply and

prioritize

We now start getting a feel for which variables are most important to explaining variation in the outputs



5-20


We have sorted on the cross-multiplied numbers and find that the input variables in the

box above are the most important

We can now evaluate the control plans for these input

variables



1 2 3 4 5 6

Bre

ak %

Melt T

em

p

Bott

le O

utp

ut

Cla

rity

Weig

ht

Wall

Variation

Total


Melt Resin Resin 9 9 3 9 9 9 324Blow Bottle Mold Design 9 0 9 9 0 9 324

Extrude Parison Programing 3 3 9 0 9 9 231Extrude Parison Die Tip Temp 3 3 3 9 3 9 228

Blow BottleMold Water Temp

9 0 9 3 0 0 198

Blow BottleWater Volume/Cooling Rate

9 0 9 3 0 0 198

Extrude Parison Head Design 3 9 3 3 3 9 180Extrude Parison Tooling 3 3 3 3 3 9 174

Blow Bottle Pinch Design 9 0 9 0 0 0 171Melt Resin Barrell Temp 3 9 9 1 3 3 168Melt Resin Screw Speed 3 9 9 1 3 3 168Melt Resin Screw Design 3 9 9 1 1 1 142

Blow Bottle# of Mold Cooling Zones

9 0 3 0 0 0 117

Tail DetabTime from extraction to Detab

9 0 3 0 0 0 117



5-21


Place the outputs across the top of the matrix and rank Place inputs down the side of the matrix starting

with the first process step and moving to the last This approach is okay for small process with

relatively few steps Should only be used for processes with a

relatively small number of steps and inputs

General Approach

5-22


Phase IPhase I Place the outputs across the top of the matrix and rank Place the process steps down the side of the matrix Correlate process step to outputs Pareto the process steps

Phase IIPhase II Start a new C&E Matrix with the inputs from the top three

or four process steps Recommended when first starting a project

o Focuses the efforts and gives the team a feeling that they’re working on the important process steps first

o Gives you a running start at the FMEA and preliminary Control Plan Analysis

Focused Approach

5-23


Standard Operating ProceduresStandard Operating Procedures Do they exist? Are they understood? Are they being followed? Are they current? Is operator certification performed? Is there a process audit schedule?

Control Plan Evaluation

5-24


Controllable Input VariablesControllable Input Variables: How are they monitored? How often are they verified? Are optimum target values and specifications

known? How much variation is there around the target

value? How consistent are they?

Other QuestionsOther Questions: How often is the input variable out of control? Which input variables should have control charts?

Control Plan Evaluation

5-1 collect & interpret data use spc to maintain current process collect & interpret data...

Documents

process inputs

process map slide

process map inputs

process steps

data examples

current process

process capability

list key inputs