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FMEA

What is an FMEA

What areas typically use an FMEA and why

How to set up an FMEA

Steps to generate an FMEA

Examples

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What is an FMEA

FMEA is a method for identifying potential failure

modes and determining their causes and effects

and planning for its elimination (or reduction).

Failure modes have scores (RPN value) that are

calculated based on severity of the failure mode

(S), likelihood of occurrence (O), and existing

control to detect the failure (D).

RPN = S*O*D

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What are the

Failure modes?

FMEA

How Probable Is theFailure?

How Serious Is the

Effect

What are the Failure

Mechanisms?

How Likely Will It

Be Detected Before ItHurts the Customer

Failure Modes and Effects Analysis Elements

Probability (O)

Consequences (S)

avoidance of

detection (D)

What Is the Effect on The Customer?

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What areas typically use an FMEA and why

Manufacturing processes

Management Systems

Design of new products and processes

Service industries to maximize customersatisfaction

Defect minimization

Identifying Safety Hazards

Each of these areas use FMEA to determine

and minimize risk.

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FMEA Template

RPNLikelihood

of

Detection

(1-10)

Control to

Detect

Failure

Likelihood

of Cause

(1-10)

Causes of

Failure

Severity

of Effect

(1-10)

Effect of

Failure

Mode

Failure

Mode

Step

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Severity Scoring of FMEA

1No effectNone

2Less than 25% of product is re-worked. Less than

25% of customers notice the defect if found.

Very Minor

325%-50% of product is re-worked. Between 25%-

50% of customer notice the defect if found.

Minor

450%-75% of product is reworked. Greater than

50% of customers notice the defect if found.

Very Low

50% of product is rejected. 75%-100% of product

reworked. Customer is dissatisfied, but loyal.

Low

625-50% of the product is scrapped without sorting.

Customer is aware of the issue and begins looking

for other suppliers.

Medium

750%-75% of product is rejected. Customer will

eventually be lost if other options exist.

High

8Between 75%-100% of product is rejected.

Customer is immediately lost if defect is detected.

Very High

9Failure is catastrophic with warningCatastrophic with warning

10Failure is catastrophic with no warningCatastrophic without warning

RankSeverity of EffectEffect of Failure Mode

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Occurrence Scoring of FMEA

2Between .000001%-.0001%Rare

1Less than .000001%Extremely Rare

3Between .0001%-.001%Very Low

8Between 50%-75%High

10Between 90%-100%Inevitable

4Between .001%-1%Low

5Between 1%-5%Moderately Low

6Between 5%-25%Moderate

7Between 25%-50%Moderately High

9Between 75%-90%Very high

RankProbability of CauseLikelihood of

Cause

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Detection Scoring of FMEA

1Greater than 99.999% chance of

detecting defect

Almost Certain

295%-99.999% chance of detectingdefect

Very High

375%-95% chance of detecting defectHigh

460%-75% chance of detecting defectModerately High

540%-60% chance of detecting defectModerate

625%-40% chance of detecting defectModerately Low

710%-25% chance of detecting defectLow

85%-10% chance of detecting defectRarely

90%-5% chance of detecting defectVery Rarely

100% chance of detecting defectNot DetectableRankLikelihood that Defect is DetectedDetection

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Steps to perform an FMEA

Determine the process and failure mode

Determine the effect of the failure mode and the

severity of the effect using rating scale

Determine the causes of the failure and the

likelihood using the rating scale

Determine the control to detect the failure and thelikelihood of detection

Calculate the RPN for the failure mode

RPN=Severity*Occurrence*Detection. The higher

the RPN score the greater the failure mode.The RPN score will be utilized to prioritize the

failure modes and develop actions to address

their occurrence.

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FMEA for Pressure Cooker

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Safety Features

1 Weight Valve and Vent Tube

Used as a pressure controller and timing of the pressure cooking

2 Gasket System

Releases the pressure if dead weight fails to act 3 Safety Valve

Acts as a fusible plug when dead weight and gasket system fail

to act

4 Proper Handle

for lifting the cooker (including contents) and to be heat resistant

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FMEA Example

402

(very high)

Time card

system

2

(rare)

All

Operators

are on

lunchbreak

1503

(high)

Budgeting

for

number ofcalls

received

5

(moderately

low)

Not

enough

operators

10

(catastrophic)

Ambulance

not

dispatched

Call is not

answered

1503

(high)

Budgetingfor

number of

calls

received

5

(moderately

low)

Notenough

operators

1806

(moderately

low)

Phone

usage logs

by phonecompany

3

(very low)

Not

enough

phonelines

10

(catastrophic)

Must wait

for open

line

All l ines

are busy

Call

108

RPNLikelihood

of

Detection

(1-10)

Control to

Detect

Failure

Likelihood

(Occurrence)

of Cause

(1-10)

Causes of

Failure

Severity of

Effect

(1-10)

Effect of

Failure

Mode

Failure

Mode

Step