Why-Why Analysis Training

Getting to Root Cause

Why-Why Analysis

• Organize Cause and Effect relationships.

• Efficient after a Cause and Effect Analysis.

• Done on:– Priority items – Pareto of the data.

Combining Various Analysis Tools

huMan equipMent

MaterialsMethods

Why-WhyM Me

Eq. H

4M Fishbone + Cause Effect Analysis + Pareto Leads To Efficient =

Carton Pickoff

CapacityBottleneck

Material equipMent

huManMethod

All of you haveprobably used a fishbone

or Cause Effect diagram at some time. In this case you begin with the

4M’s.

Be very focusedin defining the

problem

Be controlled indefining the branches

for the tree. Eachbranch will require

study.

Cause - Effect diagram

Product of Why-Why Analysis

It is a structured, field checked, relationship with each cause-effect relationship linked from the lowest element back to the phenomenon.

Steps to Follow

1. Understand the Problem

2. Establish Cause-Effect Relationships

3. Review the Analysis

4. Check Standards and SOP’s.

5. Establish Countermeasures

1. Understand the Problem

a) According to the Process requirements.

b) According to the physical causes of the phenomenon.

• First “Why” about the Phenomenon– The question needs to be answered for each element

involved in the description made in the previous step.– This question needs to be answered from a physical

and/or logical point of view.

– At this point, focus on the evidence of the flaws:• Verify the evidence of the causes of the problem in

the field (whether it exists or not, stopping the analysis for that branch when the cause no longer exists.)

• If it is possible to put a direct countermeasure to the cause into place, do it and stop the analysis. Ensure that procedures or standards are in place to maintain condition achieved..

2. Establishing Cause-Effect Relationship.

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• Second “Why”For each answer to the “Why?” in the previous

step, the question “Why?” is asked again.

The answer in this case, and from here on, should consider the “4 M’s.”

2. Establishing Cause-Effect Relationship.

12/15/9909B00_01.ppt Page 10

Problem

Why? 1

MissingCarton

Pulling Force Not

Strong Enough

ForcesHoldingCarton

toohigh

Why? 2Seal

betweenSuction

Cup and Carton

inadequate

VacuumForceNotHigh

Enough

CartonsStickingTo EachOther

HoldingFingers

MissAdjusted

HoldingFrame

TooTight

Why? 4

Duston

Carton

Scratcheson carton

SurfaceFinish

outside tolerance

Why? 3

SuctionCup

Damage

PoorCartonSurface

Condition

VacuumSettingtoo low

VacuumLine

Leaks

SuctionCup

Too Small

SuctionCup

InadequateMaterial

SuctionCup

Wear

Field Check

No Wear

No Damage

Could be

Yes

Yes

Not True

No

No

Could be

Phenomenon

Once you have exhausted your Why-Why Questioning, do the Cause-Effect Relationships Make Sense and flow back to the Phenomenon ?

3. Review the Analysis

Note: Thereis a morecompletereview ofthis Carton Pickoff example at the end of this section

12/15/9909B00_01.ppt Page 11

4. Checking for Standards and SOP’s

Problem

Why

?

Why

?

Why

?

Why

?

Why?

Root

Cause

Std.’sExist?

Action

Taken?

Action

Standards(4M’s)

huMan

equipM

Method

Material

SOPExist?

OK

NOK

XX

X

Applied?

Field

Check

Y

N

YN Restore

NewStd.

NewMaint.Std.

YN

WHY-WHY

Before taking counter measures, check to see if standards for the defined counter measure exist. If not, define the standard. Determine if an SOP is needed.

Use the 4M’s to ensure all requiredtypes of standards exist.

Also use AM Step 5 data base for Ideal Oper.Conditions

5. Establish Countermeasures.

The analysis should be done at the problem area, not in another location that is isolated from the case (like an office).

The analysis is a team effort, not by just one person. More eyes will see more causes.

The most important thing is the physical and/or logical description of the phenomenon to be studied. (Step 1)

ALWAYS make a sketch or drawing of the phenomenon.

The Analysis ends when countermeasures TO AVOID RECURRENCE of the phenomenon are found and restored or changes implemented using the MP Data System.

Real WHY-WHY Analysis ExampleProblem: Through put of the line 23 is below ideal.

Phenomena: Carton not Picked off the supply stack.

Result: This causes a loss in through put. (Missing Carton)

MissingCarton

Phenomenon

Why

?

1

MissingCarton

Pulling Force Not

Strong Enough

ForcesHoldingCarton

toohigh

Why? 1

MissingCarton

Pulling Force Not

Strong Enough

ForcesHoldingCarton

toohigh

Why? 2 SealbetweenSuction

Cup and Carton

inadequate

VacuumForceNotHigh

Enough

CartonsStickingTo EachOther

HoldingFingers

MissAdjusted

HoldingFrame

TooTight

Phenomenon

Why? 1

MissingCarton

Pulling Force Not

Strong Enough

ForcesHoldingCarton

toohigh

Why? 2 SealbetweenSuction

Cup and Carton

inadequate

VacuumForceNotHigh

Enough

CartonsStickingTo EachOther

HoldingFingers

MissAdjusted

HoldingFrame

TooTight

SuctionCup

Wear

Why? 3

SuctionCup

Damage

PoorCartonSurface

Condition

VacuumSettingtoo low

VacuumLine

Leaks

SuctionCup

Too Small

SuctionCup

InadequateMaterial

LooseCartonStack

Flapsfolded

Backward

Phenomenon

Why? 1

MissingCarton

Pulling Force Not

Strong Enough

ForcesHoldingCarton

toohigh

Why? 2

SealbetweenSuction

Cup and Carton

inadequate

VacuumForceNotHigh

Enough

CartonsStickingTo EachOther

HoldingFingers

MissAdjusted

HoldingFrame

TooTight

Why? 4

Duston

Carton

Scratcheson carton

SurfaceFinish

outside tolerance

Why? 3

SuctionCup

Damage

PoorCartonSurface

Condition

VacuumSettingtoo low

VacuumLine

Leaks

SuctionCup

Too Small

SuctionCup

InadequateMaterial

SuctionCup

Wear

LooseCartonStack

Flapsfolded

Backward

Phenomenon

Case Study