失效模式及其影響分析講座英文版

失效模式及其影響分析講座英文版FMEACourseSchedule

Day2 9.00 Real-lifeP-FMEAexercise-con’t Review

10.30 Tea-break 10.45 D-FMEA

12.00 Lunch 1.00 OrganizationAspectofFMEA 3.00 Tea-break 3.30 MaturityGrid

Day19.00 Introduction IntrotoFMEA ProcessFMEA10.30 Tea-break10.45 Process-FMEA(con’t) 12.00 Lunch 1.00 Real-lifeP-FMEAexercise 3.30 Tea-break 3.45 Real-lifeP-FMEAexercise-con’t 1

INTRODUCTION

TO

FMEACar2:NoMajorBreakdowns

非主要的破損Fewfailures

很少的失效Car1:FrequentBreakdowns

頻繁地破損Manyminorcomponentsfailures

許多的小部件失效Areliabilityprogram?Whynecessary?

一個可靠性的計劃？ 為什么必須？

CustomerSatisfaction－顧客滿意Customersatisfactionmeans:Neverhavingtosayyou’resorry!

顧客滿意意味著：決不要說對不起！

QUALITYENGINEERINGTOOLS

TOOLS 1DesignReview 27QCTools 3New7QCTools 4StatisticalProcessControl 5DesignofExperiments 6QualityFunctionDeployment 7FailureModeandEffectsAnalysis

APPLICATIONDesignQualityAssuranceDataanalysis/Problem-solvingBusinessProcessMgt,QFPHoldingtheimprovementQualitybreakthroughsMeetingcustomerrequirementFool-proofDesign&processes

WhatisaFMEA?Astructured,disciplinedprocesstosystematicallyandcomprehensively,identifyanddocumentpotentialproblemsandweaknessesinadesignorprocesssothatdesignchangescanbemadeorothercorrectiveactionstakentopreventactualoccurrenceoffailure

一個結(jié)構(gòu)化和

專業(yè)化的過程，它能系統(tǒng)和綜合地找出并記錄在設(shè)計和工藝過程中潛在的問題和缺點并由此作出設(shè)計改變或采取其它的改正措施以防止失效的實際發(fā)生EffectofFMEAonProcessandDesignchangesDesignStartDevelopmentProductionReleaseProductionTimeNoofEngineeringChangesTraditionalapproachFMEAapproach

TYPESofFMEATYPE ALIASES DESCRIPTIONProduct DesignFMEA *Focusontheproductitself,reviewFMEA D-FMEAsystems,parts&componentsProcess ProductionFMEA *Focusonthemanufacturingprocess,FMEA P-FMEA revieweachprocessstepApplication Downstreamcustomer’s*Focusoncustomer’sprocessFMEA ManufacturingFMEA *Primarilyinterestedincompatibilitybetweenyourproduct&customer’s processService *Focusonfieldservice FMEA *Concernedwithreliability,product application,maintainability ObjectiveofFMEAFailureMode&EffectAnalysis(FMEA)isusedtoimproveproductreliability(consideringusage,environment,lifetimeetc.)qualityof(purchased)parts(incl.‘hidden’functionsofapart)reproducibilityoftheproduct(reductionoffalloff&repairsinassembly)reproducibilityoftheproductionprocess(handling,transportetc.)FocusontechnicalproblemsLinkwithMaturityGridandRiskManagement!TypesofRisksMarketRisks

havingtherightproduct

ontherighttime

TechnicalRisks

achievingtheproductspec

quality,reproducibilityProjectRisks

projectorganisation,

teamaspects,resourcesMarketRisksTechnicalRisksProjectRisksPlanningSpecificationKnow-how,capacityUseofFMEAA.ReliabilityEngineering -Reliabilityimprovements.B.ProducibilityAnalysis -Lessrepairsandscrapduringmanufacturing. -ImprovementoftheZero-HourQuality.C.ProductionProcessAnalysis -Lessrepairsandscrap. -Determinationofprocesscontrolpoints. -Processrelease.AandBduringdevelopmentphase.Cduringworkpreparationphase.100:110:11:1PRODUCTDESIGNPROCESSDESIGNPRODUCTIONIMPROVEPRODUCTPAYBACKSLOWVISIBILITY/REWARDHIGHVISIBILITY/REWARDTIME500:1CONCEPTDESIGNQualityLeverReliabilityInvestigationbyMeansofFMEAPremises: ThenormalfunctioningoftheproductQuestion: Whatistheinfluenceof:use-timeand environmentoneachcomponentPossibilities: a.wear, b.rust, c.materialfatigue, d.contamination,e.deformationunderload(creep) f.ageing, cessfailures.Whatistheeffectonproductfunctions?ProducibilityAnalysisbyMeansofFMEAPremises: Measuringtoolis:egFOR/ppmActions: Actionsasoutcomeofthe ProcessQualityControl(P.Q.C.)Analysis: Focusedonfailureswhicharemadeandnoticed duringtheproductionprocess.2

PROCESSFMEAFMEAfortheProductionProcessSubjectforAnalysis: -flowchartandscenarioofthe productionprocessFocusedon: -manipulationsoftheoperator -wrong(deviations)material -process -equipment -transport -storageFailuremodeRPN2=SO2D2ControlsCause1RPNn=SOnDnControlsCause1DevelopmentofaProcessFMEA:AnOverviewProcessstepPurposeRPN1=SO1D1ControlsCause1EffectsSeverity,SOccurrence,OnDetection,DnProcessFMEAProcedure5Steps:EstablishtheProcessFlowAnalyzetheProcessEstablishpurposeofeachoperationandthepossiblefailuremodesDefinetheweakpointsoftheProcessEstablishactionsandresponsibilitiesStep1-EstablishProcessFlowTakeintoaccountthe:SpecificationformanufacturingSystemStructure:

- manufacturingstrategy(manual/automaticetc)

- technologies,processes&equipment

- line&factorylayout

- suppliers,transport,materialflowSystemoperation,controlandmaintenanceSystemenvironmentalconditionsTesting&qualitycontrolMakeoftheassemblyprocessa:PROCESSFLOWCHARTProcessFlowChart(eg)MountpartHandlingprocessGluepartAdjustmentprocessTestingMountsubassyHandlingprocessMountpartTestingStation1Station2Station3Station4ProcessFlowChart(eg)EquipmentsLightpencarrierLightpencarrierPress-ontoolLightpencarrierMountingfixtureElectricscrewdriverScrewdispenserLDGUcutting/insertionmachineLightpencarrierSolderingequipmentGratingadjustmentmachineGluedispenserandcuringunitMountactuatr&installspringclipMount&secureflexassemblyCutLDGUleads&mountLDGUintoLightpenhousingSolderactuatorandLDGUtoflexassyGrating&glueingofLDGUMountrack&wirespringAssemblyprocessFailureModeandEffectAnalysisChartStep2-AnalysisoftheProcessExaminationof:Howthepurposeoftheprocess/operationarerealisedbythedesigners/engineers.Whataretheworkingconditions *static *dynamicStep3-EstablishpurposeofeachoperationandthepossiblefailuremodesWhatisthepurposeoftheprocessstep?Whichdeviationsarepossible? (FAILUREMODE)Whatistheeffectofthatdeviationontheproducibility?(EFFECT)Whatisthecauseofthatdeviation? (CAUSE)MATERIALMANMACHINEMETHODMEASUREMENTENVIRONMENTPROCESSProductFunctionsProductFunctionsProductFunctionsProcessCause-EffectInvestigationPOTENTIALCAUSEEFFECTPOTENTIALFAILUREPOTENTIALPotentialFailureModesFailuremeansanyoneormoreofthefollowing… - failuretoperform/deliverfunction - failuretomeetdesignintent - failuretomeetcustomerexpectations - somethingundesirable,e.g.anoisyprojector - applicationproblem,e.g.wrongapplicationfailurecouldoccur,butwillnotnecessarilyoccurdescribein“physical”ortechnicalterms,notasasymptomrecognisablebythecustomerusebrainstormingtoensurecompleteness

Examples:corrodedcrackeddeformedoxidisedleakingfracturedmalformedflattenednon-stickingcontaminatedFailureModeandEffectAnalysisChartEffects(ProcessFMEA)Eachfailuremodemayhaveundesirablesideeffectsonsomeorallthefollowing: 1. End-user(product) 2. Down-streamprocess(nextoperation) 3. LocalprocessAll3effectsshouldbeconsideredinanyprocessFMEASeverity(Process-FMEA)Rating Degree Effectson Effectondown EndUser Stream/Localprocess 1 Minor*notnoticeable *noeffect 2 low*slightlynoticeable *noimpact/limitedeffect 3 *limitedimpactonboth 4 Moderate*custdissatisfaction *mayrequireminorrework 5 *reducedperformance *mayreq.unscheduledrework 6 *perform.Deterioration *maycausedamagetoequip. 7 High*highdeg.ofcustdissatisfaction *maycauseseriousdisruption 8 *lossofsub-systemfunction, *mayrequiremajorrework mayendangermachine/operator 9 Veryhigh*safety-related *productionlineshutdown10 *non-compliancewith *saftetyofprodpersonnelthreatened governmentregulations~SeverityistheassessmentoftheseriousnessoftheeffectFailureModeandEffectAnalysisChartPotentialCause(s)ofFailureHowthefailuremodecouldoccur,describedintermsofsomethingcorrectableorcontrollablelist,usingbrainstormingorFaultTreeAnalysis(FTA),everyconceivablefailurecauseassignabletoeachfailuremodecausesshouldbespecific,e.g.“operatorerror”or“machineproblem”areexamplesofcauseswhicharenotspecificenoughcausesmayormaynotbemutuallyexclusive - iferadicatingacausehasadirectimpactonthefailuremode,then, thecauseissaidtobeexclusivetothefailuremode

- whencausesarenotmutuallyexclusive,DesignofExperiments

maybeusetoidentifytherootcauses(minorcontributors)orthose whichcanbemosteasilycontrolledFaultTreeexampleProblemCauseACauseBCauseCA1A2B1B2Occurrence(P-FMEA)Rating Degree BasedonSPC Baseonfailurerate 1 Remote CpK>1.67 <1ppm 2 Verylow CpK>1.33 50ppm 3 Low CpK>1.00 250ppm 4 1000ppm 5 Moderate CpK<0.83 2500ppm 6 1in80(1.25%) 7 High NotinStatistical 1in40(2.5%0 8 control 1in20(5.0%) 9 Veryhigh Failurealmost 1in8(12.5%)10 inevitable 1in2(50.0%)~canbethoughtastheprobabilityofoccurrenceofthefailuremodeFailureModeandEffectAnalysisChartCurrentcontrolsCurrentcontrolsaredescriptionsofcontrolsthat: (a)preventthefailuremodefromoccurring

or (b)detectsthefailuremodeshoulditoccurExamplesofprocesscontrols: -fixturefool-proofing -SPC -inspectioneitheratthesubjectoperation -testingoratthesubsequentoperations -gaugeR&R -preventivemaintenance -operatortraining -GMP(goodmanufacturingpractice) -ISO9000 -SOP(standardoperatingprocedures) -humidity/pressure/tempcontrols -finiteelementanalysis -calibrationDetection(P-FMEA)Rating Degree Description1 VeryHigh Processautomaticallydetectsfailure2 Controlwillalmostcertainlydetectfailure3 High Controlhavegoodchanceofdetectingfailure4 5 Moderate Controlmaydetectfailure6 7 Low Controlhavelowchanceofdetectingfailure8 9 VeryLow Controlprobablywillnotdetectfailure10 Nil Controlwillnotdetectfailure~Assumethefailurehasoccur,assesstheprobabilitythatthecontrolswilldetectthefailuremodebeforeshippingoutFailureModeandEffectAnalysisChartStep4-DefinetheWeakPointsDefinetheseverityofthefailure(=S)

Effect Rating:1.........10Definetheprobabilityofoccurrenceofthefailure(=O)

Cause Rating:1........10Definethelikelihoodofdetectionofthefailure(=D)

TimeEffect Rating:1........10RiskPriorityNumber:(RPN)

=>SeverityxOccurrencexDetection => RPN=SxOxD

1<RPN<1000 Inthemselves,absoluteRPNnumbershavenosignificance.Theyareonlyforrankingthefailurecauses,forcorrectiveactionsRPN:AcceptancethresholdS=5(reducedperformance+degradation)O=5(approximately0.25%)

D=5(maydetectpriortoshipment)Generally,RPN125maybeagoodthresholdtouseieforRPN>125=>correctiveactionisneeded.Butthereareexceptions;SxOxDRPN 125S O D Description Action?10 1 1 Failureunlikelytoreachuser1 10 1 FrequentMinor,detectablefailure1 1 10 Minordefectreachesuserinfrequently10 10 1 Seriousandfrequentfailure1 10 10 Frequentminordefectreachesuser10 1 10 Seriousdefectreachesuser10 10 10 INTROUBLE!!!Step5-EstablishActionsandResponsibilities1.Whathastobeimproved:-changeofdesign-lifetest-contactwithsupplier-controlpointbuildin,inproductionprocessetc.2.Whoisresponsible3.WhenisitfinishedRPNacceptable?CorrectiveactionsDONewRPN1Acceptable?EndYesNoNoYesRPNacceptable?CorrectiveactionsDONewRPNnAcceptable?EndYesNoNoYesChoiceofCorrectiveActions

Unlikelytobeeffective Preferredchoices

* Increaseinspection * Poka-yoke(fool-proofing) * Additionaltest * Processchange * Additionalcheck * designchange * Re-trainoperators * Automation * Re-writeSOP * Computerisation * Robotics

CorrectiveActionPreferenceHierarchyTheintentofanyrecommendedcorrectiveactionistoimprovetheRPNratingbyreducingSeverity,Occurrence,Detectionorall3together.Emphasisshouldbeonprevention,i.e.reducingOccurrence.Shouldpreventionbeimpossible,thefollowingHierarchyofpreferenceshouldbeused: 1.Prevention,orpotentialcauseelimination 2.Detection,asearlyintheproductlifecycleaspossible: best ………atthedesignstage nextbest ………priortomassproduction then ………priortoshipment and,aslastresort………inthefield,priortocatastrophicfailure 3.Impactreduction,i.e.reduceSeverityGenerally,toreduceanyofthethreerating-O,D,S -processand/ordesignchanges/modificationarerequiredFMEA

is isnot

*structured *ashow-piece *systematic *anumbergame *rigorous *aguessinggame *comprehensive *adocumentationexercise *scientific *aself-consolationexercise *adiscipline .. *preventive .. *customer-focused .. *ateameffort .. *across-functionalexercise .. *alivingdocument .. *acontinuousprocess *aone-offexerciseRealLifeFMEAExercise3

PRODUCTD-FMEAProcessFMEAvsProductD-FMEA* P-FMEAdoesnotrelyonproductdesignchangestoovercomeprocessweaknesses,butitdoestakeintoconsiderationaproduct’sdesigncharacteristics* D-FMEAdoesnotrelyonprocesscontrolstoovercomedesignweaknesses,butitdoestakethetechnical/physicallimitationsofthemanufacturingprocess(i.e.theprocesscapability)intoconsideration.ProcessstepPurposePiece-partorsub-assyFunctionProcessFMEAProductFMEAProcessFMEAvsProductD-FMEA* Hencecausessuchas“operatornotinsertingresistorproperly”&“suppliershippingwrongparts”maynotbeofconcerninaD-FMEA,butiftherearedesign-relatedfactorsthataffectinsertion,orwhichcausetransportation/shippingproblems.,thentheymustbeconsidered.ProcessstepPurposePiece-partorsub-assyFunctionProcessFMEAProductFMEADesignFMEAAD-FMEAstartsfrom aBill-of-MaterialorFunctionalBlockDiagram

DesignFMEAcantakeeitherof2approaches:1. ComponentsBottom-upApproach Thisapproachispossibleonlywhenadesignalreadyexists. Itservestojustifyeverycomponentinthedesign.DesignFMEA2. FunctionalBlockApproach(Top-down) Thisapproachhelpsdesignerspicktheoptimalsub-systemsorsub-assemblies.Itplaysapartinthedesigndecision-makingprocess Inthecaseofbig,complicatedsystems,theSelectiveFunctionalBlockApproachmaybeused--ateachleveloftheFunctionalBlockDiagrampickthemostsusceptiblesub-assyofsub-systemtoFMEAProductFunctionsTakeintoaccountthe:SpecificationSystemStructure:

- differentelementswiththeircharacteristics,performanceroles andfunctions

- connectionsbetweenelementsSystemoperation,controlandmaintenanceSystemenvironmentalconditionsUserspatternMakeofthefunctions,subsystemsandcomponents:==>FUNCTIONTREEProductFunctionTreeProductbasicfunctionFunctionAFunctionBFunctionCFunctionDFunctionAaFunctionAbFunctionCaFunctionCbFunctionAbaFunctionAbcFunctionCaaFunctionCabFunctionCacEffects(D-FMEA)3levelsofeffectsmustbeconsidered: 1.End-usereffects 2.Nexthigherleveleffects 3.LocaleffectsThefollowingexamplewillhelptodistinguishthe3typesofeffects:valveenginesystempowersystemcar

component nexthigher end-userunderreview level Effect Description ExampleEnd-usereffects effectsoncarperformance; noisy;jerky;cannot whatthecustomerwouldobserve runathighspeed and/orexperienceNexthigherleveleffects effectsontheengine over-heated;vibrationLocaleffects effectsonthevalveitself deteriorationMATERIALUSEDESIGNCOMPONENTSPECIFICATIONENVIRONMENTPRODUCTPOTENTIALCAUSEEFFECTPOTENTIALFAILUREPOTENTIALProductCause-EffectInvestigationProductFunctionsProductFunctionsProductFunctionsSeverity(D-FMEA)Rating Degree Effects 1 Minor *noperceptibleeffectonproductperformance *userwillprobablynotnoticethefailure 3 low *customernoticesslightdeteriorationinperformance *causesslightcustomerannoyance 5 Moderate *causessomecustomerdissatisfaction *customernoticesreducedproductperformance *gradualperformancedeterioration 7 High *highdegreeofcustomerdissatisfaction *lossofsub-systemfunction,eg.enginefail 10 Veryhigh *safety-related *non-compliancewithgovernmentregulationsOccurrence(D-FMEA)Rating Description Probabilityoffailure Designlifefailurerate 1 Remote Failureunlikely <1ppm 3 Low Relativelylowfailurerate 200ppm

1000ppm 5 Moderate Occasionalfailures 2500ppm 1in80(1.25%) 7 High Repeatedfailures 1in40(2.5%0 1in20(5.0%) 10 Veryhigh Failurealmostinevitable 1in8(12.5%) 1in2(50.0%)Detection

Approach Description Application Time-table Howearlyinproductlifecycle D-FMEA fromdesignstarttoFieldfailure? Fixed-gate What’stheprobabilityofdetection D-FMEA atanypoint(gate)inthecycle?Detection(D-FMEA)Time-tableapproachRating Probabilityofdetection1 WillbedetectedpriortoProductionRelease3 VerylikelytobedetectedpriortoFinalRelease4 DetectableafterreleasebutbeforeMassProduction5 DetectablepriortoShipment7 Willbedetectedbeforeoccurrenceinthefield10 UndetectableuntilfailureoccursinthefieldDetection(D-FMEA)FixedGateapproachRating Probabilityofdetection1 Willbedetectedindesignevaluations3 Highchanceofdetectionindesignevaluations5 Moderatechanceofdetectionindesignevaluations7 Lowchanceofdetectionduringdesignevaluations10 Undetectableuntilfailureoccursinthefield4

ORGANIZATIONALASPECTSOF

FMEAOrganisationalAspectsofFMEAGeneralPointsParticipantsPreparationsReportingFMEAisateameffortcoveringallrelevantdisciplinesFMEAsessionsshouldnotlastlongerthanhalfadayTheproductFMEAshouldbefocusedon:

-reliability(normalfunctioning)

-producibilityTheprocessFMEAshouldbefocusedon:

-processflow -manipulationsofoperator -deviationsinmaterial -transport

-storage

GeneralPointsFMEA:CriticalSuccessFactors* Behonest* Bepositive* Bethorough* Attentiontodetails* Followthrough* Involvetherightpeople* “Ratherbesafethansorry”* Managementbyfact - Minimiseguess-workandgut-feel - MaximiseuseofdataandquantitativemethodsParticipantsParticipantsshouldbedirectlyinvolvedNumberofparticipantsshouldbelimitedParticipantsfromrelevantdepartments:

-Development

-Engineering

-Production

-Process -Quality -Specialist(ifnecessary) -ServicePreparationsforD-FMEAPreparationsshouldbedonebythedesigner,incloseco-operationwiththechairmanofthemeetingDrawingsandsufficientmodelsshouldbeavailableOnemodelshouldhavebeenincirculationTolerancecalculationsandcontourmapsshouldbeavailableSpecialpreparationsforaD-FMEA:

-thedesignshouldbebreakdowninto‘elements’

-prioritysettingsoftheseelements

-fromexistingproductsthefollowingdatashouldbeavailable:

.Presaledata

.Servicecallr