07 failure modes and effects analysis

8/13/2019 07 Failure Modes and Effects Analysis

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07 Failure Modes andEffects Analysis

(FMEA)

Measure ControlImproveAnalyzeDefineRecognize

2004 American Society for Quality. All Rights Reserved.

Six SigmaGreen Belt Training


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AnalyzeMeasure ControlImprove Page 2 FMEA Version 2.1

Define

ControlImproveAnalyzeMeasureDefine

About This Module

Six Sigma, A Quest for Process Perfection Attack Variation and Meet Goals

An FMEA is a systematic method for identifying, analyzing,and documenting potential failure modes and their effectson the system, the product and process performance. Thepossible causes of failure can then be prioritized.

\DataFile\Fishbone.mtw\DataFile\FMEAform.xls\DataFile\CopyProc.ppt\DataFile\CopyFMEA.xls\DataFile\CpultPM.ppt\DataFile\CauseEff.ppt


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Define


Sample FMEA

Company: Copying Company Project: Copying Process

Part/process

FailureMode

FailureEffects

S

E V Causes

O

C C Controls

D

E T

R

P N Action Recommended Resp.

Person Schedule

Date Action Taken

ActualCompl.

Date p S p O

p D

p r

p n

R i s k

RiskX

prpn

RetrieveCopies

NoCopies

Mustredocopy 7 Paper Jam 9

PeriodicMaint. 7 441

Ensure proper weight and typepaper avail for copiers Key Opr 3/1

Ensured propersupplier used to

provide copypaper 2/15 7 3 7 147 3 441

Set SizeRequired

Copy iswrongsize

Mustredocopy 7

Usermisset size 7

Existingnotes oncopier 5 245

Place sign over copier outliningstandard size enlarge/reduce orreliable mach to clearly indicate

standard reduce/enlarge Key Opr 2/20Place sign over

mach 2/15 7 3 2 42 1 42

Set Light/Dark Copytoo light

Must

redocopy 7

User

missetcontrol 5

Existing

notes oncopier 4 140 Place sign to encourage user toutilize auto settings Key Opr 2/20 Place sign overmach 2/15 7 2 2 28 1 28

PlaceDoc intoPosition

Copynot

alignedproperly

Mustredocopy 7

Usedlandscapeinstead ofportrait orvice versa 8

TraySelection 2 112

Place note on ruler re trayselection Key Opr 1/20 Placed Note 1/15 8 2 1 16 1 16


Copynot

alignedproperly

Mustredocopy 7

alignmarkingnot clear 4

Use AutoFeeder /

align ruler 3 84Enlarge marks for 8.5 " paper on

ruler Key Opr 1/15 Enlarged marks 1/14 7 2 1 14 1 14


Copynotalignedproperly

Mustredocopy 7

Docmovedwhen lidclosed 5

Use AutoFeeder /

align ruler 2 70

Place sign over copier re"Ensure align prior to copying or

use auto Feeder" Key Opr 1/15 Displayed Sign 1/14 6 1 1 6 1 6

SelectPaperTray

Copy onwrongpaper

Mustredocopy 7

Userselected

wrong tray 3

Autoselect

function 3 63

Place sign over copier toencourage user to use auto tray

select Key Opr 2/25Place sign over

mach 2/20 7 2 3 42 1 42Place

Doc intoPosition

Spotson

copies

Mustredocopy 7 Dirty Glass 6

PeriodicCleaning

SOP 1 42Place cleaning material near

copier Maint. 1/15Placed Cleaning

Matl 1/15 6 1 1 6 1 6


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Define


Why Use FMEAs?

Identify ... critical product characteristics and process variables

Prioritize ... product and process deficiencies in support of downstreamimprovement actions

Help focus ... on prevention of product and process problems


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Define


Benefits of FMEAs

Improves the quality, reliability and safety of products.

Helps increase customer satisfaction.

Reduces product development timing and cost.

Reduces the amount of rework, repair and scrap.

Documents and tracks actions taken.

Prioritizes deficiencies to focus improvement efforts.


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Define ControlImproveAnalyzeMeasureDefine

Process - Level #1

Step #1 Step #2

Process - Level #2

Step #1 Step #2

Process - Level #3

Step #3

Step #1 Step #2 Step #3

FMEA - Level #1

FMEA - Level #2

FMEA - Level #3

Step #3

Process and FMEA Hierarchies


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Process FMEA Steps

1. Identify Heavy Hitter Process Step

2. Identify Associated ys (ProductParameters)

3. Failure Mode

4. Identify Failure Effects/Rate Severity

5. Identify Causes/Rate Occurrence

6. Identify Controls (if any)/Rate Detection

7. Calculate RPN

8. Prioritize by RPN Order

9. Determine Actions/Plan

10. Recalculate RPN Based on Plan

11. Take Action

Prior to FMEA: Charter TeamDevelop andCharacterizeProcess Map


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Header Accessible fromView Header/Footer

in Excel

Workbook in Excel

FMEA Form

\DataFile\FMEAForm.xls


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Cause(xs)

FailureMode

Effect (ys)

Cause-Failure Mode-Effect Continuum


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The Cause and Effect Diagram Example

Admin/Service Example

First produced in 1950 byProfessor Kaoru Ishikawa- Also called the:

Ishikawa Diagram Fish Bone Diagram

Developed to representthe relationship betweensome effect and allpossible causesinfluencing the effect.

FailureEffect

Failure Mode(Defect)

Measurements Materials Personnel

Environment Methods Machines

\DataFile\CausEff.ppt Enter causes for each of the 6M branches. Expand or add text boxes as required.


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Cause and Effect Diagram Example (cont.)

The Memory Jogger TM

Lab Results Delays Room too hot

Room too cold

Patient not in room

Cant procurespecimen

Courtesy visits

Info desk delays

Centrifuge not avail

Info link

Analyzers not avail

Time of bag spec

Order slip delays

Specimen notsufficient

Multiple ResultsPoor identification

Analyzer out of cal

Plastic bags

Ice

Environment MachinesMethods



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Process: Making a Copy

INPUTS

INPUTS (Xs) OperatorCopy MachinePaperPowerInstructionsDocument to Copy

Set SizeRequired

PlaceDoc into

Position in/onCopier

.

SetLight/DarkSettings

.

SelectPaperTray/Source

Set Numberof

CopiesNeeded

OUTPUTS(Ys) Copies with:

rightnumber rightcontrastcorrectorientation right size on rightpaper

OUTPUT

(xs ) N Hinges on LidCR Auto FeederN Glass Clean

(xs)

C # CopiesButton

CR # CopiesRequired

(xs) N Size displayC Size buttons

(xs)

C DarkerButton

C LighterButton

C AutoButton

(xs) C 8.5 X 11:Landscape

C 8.5 X 11Portrait

C 8.5 X 14Landscape

C 8.5 X 14Portrait

C 11 X 14

C Trays withadequatesupply of paper

Product ( ys ) Doc setcorrectlyDoc setincorrectly

UpsideDownSideways

Product ( ys )Correct # ofCopiesIncorrect # ofCopies

Product ( ys ) Right sizeselectedSize tooSmallSize tooLarge

Product ( ys )RightcontrastToo LightToo Dark

Product ( ys ) Correct TraySelectedIncorrect TraySelected

PressCopy Button

(xs) CRCopy ButtonN Leds

Product ( ys )MachineproducingcopiesMachine notproducingcopies

RetrieveCopies

(xs) C Output Tray

Product ( ys )Copiesavailable

KEY for (xs) Process Parameters

N Noise ParametersC Controllable Process ParameterS SOP ParametersCR Critical Parameters

\DataFile\CopyProc.ppt


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Step 1: Identify Heavy Hitter Process Step

From the Process Map, identify the process step with themost likelihood of having failure modes with significanteffects.

Use defect data and/or team knowledge about failuremodes when selecting process steps.

Significant impact to the business? (COPQ, cycle time,fill rate, ...)

Use a Cause and Effect Diagram to capture brainstormingresults.

After completing FMEA Steps #2-7 for all failure modes

associated with this process step, return to this step andselect the next most likely Heavy Hitter process step.

Not all process steps will need to be analyzed by theFMEA.


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Step 5: Identify Causes/Rate Occurrence

Identify the most likely causes for each failure mode using aCause and Effect Diagram :

CAUSES are the conditions that bring about the Failure Mode.

Transfer the resulting information to the FMEA form.

Assign an occurrence value (1-10) to the likelihood that eachparticular cause will happen and result in the failure mode.

The occurrence score for each cause should be related to thelikelihood of that cause resulting in the failure mode and producingthe specific associated effect.


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Organize Brainstorming Ideas

What other causesshould we add?

Copy Misaligned

Copy Process Fishbone

Out of cal Wrong size paper Select wrong orientation

Humidity Doc moved whenlid closed Align marking not clear

Environment MachinesMethods



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Creating a Fish Bone Diagram in Minitab

Lets create the fish bone diagram on the previous page usingMinitab

Minitab will allow you up to six bones on your fish

For manufacturing, the bones are typically

Measurements

Materials Personnel

Environment

Methods

MachinesGive the bones any name you wish

Identify a measurable undesirable effect for the head

Brainstorm causes and assign each cause to a bone


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Fish Bone Diagram in Minitab (cont.)

Approach:

Open Data FileFISHBONEThe data have beenentered in columns C1 through C6 (normally,you would enter yourown data)Go to Stat > QualityTools > Cause-and-Effect

The dialog box Causeand Effect Diagram willappear as shown


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1. Highlight Personnel2. Push Select3. Personnel will appear

in the Causes windownext to the Label forPersonnel

4. Repeat for all Labels

1

2

3

4


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MisalignedCopy

Environment

Measurements

Methods

Material

Machines

Personnel

Selected wrongorientation

A lign marking not clear

Wrong size paper

Doc mov ed when lid

closed

O ut of calibration

Humidty

Copy Process Fishbone


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Step 6: Identify Controls (if any)/Rate Detection

Identify the current mechanisms in place which prevent thecause from occurring, or detect it before the product reachesthe customer. Some examples of controls are SPC, training,maintenance, inspection, SOP etc.

Assign a detection value (1-10) based on an assessment ofthe likelihood that the current control mechanisms will detectthe cause of the failure mode before it reaches the customer.

Dont agonize over detectability.


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The product of the estimates of severity

occurrence and

detection .

The RPN provides a relative priority for taking action;the bigger the RPN, the more important to address.

RPN = SEVERITY x OCCURRENCE x DETECTION

Step 7: Calculate Risk Priority Number (RPN)


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8: Prioritize by RPN OrderUse the Sort command in Excel to order the spreadsheet indescending order of Risk Priority Number (RPN).

9: Determine Actions/PlanBased on the causes found, determine actions that willminimize the effect of each cause, in priority order.

Steps 8 and 9


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10: Recalculate RPN Based on Plan

Assuming the actions are carriedout successfully, reassignseverity, occurrence anddetectability.

Place these new ratings in thepredicted columns (ps, po & pd).

Assign a rating from 1 to 5 foreach action that will show therisk associated with each action(5 being the greatest risk ). Placethe rating in the risk column.

Steps 10 and 11

11: Take Action Based on the riskmitigation column(Risk * prpn), take theactions indicated orreassign actions.

Complete theactions indicated by

the times stated!


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Steps 1-11:

\DataFile\CopyFMEA.xls

Company: Your CompanyProject: Copying Process FMEA

Page 1 of 1Printed on 4/5/00 2:37 PMOwner__Key Operator__

Step 5Step 3 Step 10Step 7 & 8

Step 2ID ys

Part/process

FailureMode

FailureEffects

SEV Causes

OCC Controls

DET

RPN Action Recommended

Resp.Person

ScheduleDate Action Taken

ActualCompl.

Datep S

p O

p D

p r p n

Risk

RiskX

prpn

RetrieveCopies

NoCopies

Mustredocopy 7 Paper Jam 9

PeriodicMaint. 7 441

Ensure proper weight and typepaper avail for copiers Key Opr 3/1

Ensured propersupplier used toprovide copy

paper 2/15 7 3 7 147 3 441

Set SizeRequired

Copy iswrongsize

Mustredocopy 7

Usermisset size 7


Place sign over copier outliningstandard size enlarge/reduce orreliable mach to clearly indicate

standard reduce/enlarge Key Opr 2/20Place sign over

mach 2/15 7 3 2 42 1 42

Set Light/Dark

Copytoo light

Mustredocopy 7

Usermissetcontrol 5


Place sign to encourage user toutilize auto settings Key Opr 2/20

Place sign overmach 2/15 7 2 2 28 1 28


Copynot

alignedproperly

Mustredocopy 7

Usedlandscapeinstead ofportrait orvice versa 8

TraySelection 2 112

Place note on ruler re trayselection Key Opr 1/20 Placed Note 1/15 8 2 1 16 1 16

Step 11Step 4 Step 9Step 6

Step 1


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Sample Process FMEA

Part/process

Failure

Mode

Failure

Effects

S

E

V Causes

O

C

C Controls

DET

RPN

Actions Plans

PS

PO

PD

PrPn

OBTAIN PARTS NO PARTS CAN'T BUILDPARTS 10

FAILED TO ORDER