FMEA-Eng-3-8-00.ppt

FMEAOutline,Section1:WhatisFMEASection2:FMEAPurposeSection3:ElementaryConceptsofFMEASection4:DevelopmentofFMEASection5:ProcessFMEAApplicationExample,ProcessPFMEAAnalysisSheet,Section1:WhatIsFMEA,WhatisFMEA,FMEAistheprefixofPotentialFailureModeandEffectsAnalysis.Thewordpotentialisomitted.FMEAisasystematicmethodwhichidentifiespotentialproductproblemsinthefollowingareas.Productdesign.Productmanufacture.Productuse.FMEAisdevelopedbyChrysler,Ford,GeneralMotors.FMEAincludingDFMEA-DesignFMEA&PFMEA-ProcessFMEA.BasedonSAEproductcharacteristic,wewillstudyPFMEAdetailedly.,FMEAHistory,Mid-60s:StartedintheAerospaceIndustries.1974:NavycreatedFMEAStandard.1976:USDepartmentofDefenseadoptedanFMEAstandard.Late70s:AutomotiveIndustriesstartedtouseFMEA.Early80s:MicroElectronicIndustrystartedtoapplyFMEAtoassistinimprovingthe“yieldofmemorydevices”.Mid80s:AutomotiveindustriesstartedtoapplyFMEAtothemanufacturingprocesses.90s:TQS9000recommendedadoptionofFMEA.,Section2:FMEAPurpose,FMEAPurpose,Controltool.Designcontrol.Manufacturingcontrol.Riskanalysistool.Managementtool.Prioritizeproductimprovementactivity.Continuousimprovementtool.Whatdowedonext?,Toreduceproductorserviceconcernsandtominimizetheprobabilityofdefectiveproductreachingthecustomer.Toidentifypotentialfailuremodesandtoratetheseverityoftheireffects.Toidentifythecriticalcharacteristicsoftheproductorprocess.Toranktheorderofpotentialdesignandprocessdefects.,FMEAPurpose,FMEAapplicationinSAE,NonconformingpreventionandcorrectionFailureanalysisQCCtools,majorcauseconfirmation,actiontaking,andeffectcomparisonOthersengineeringarea,Section3:ElementaryConceptsofFMEA,FMEAConcepts,Function,whatissupposedtohappenhere.Whatistheproductorprocessobjective.FailureMode,whatcangowronghere.TwoTypesoffailuremodes.Failuretoperformtherequiredfunction.Performsfunctionpoorly.Performsafunctionthatisnotsupposedtobethere.Cause,howcanitgowrong.Fourtypesofpossiblecauses.Designrelated.Manufacturingprocessrelated.Applicationrelated.Servicerelated.,FMEAConcepts,Effect,whathappenswhenitgoeswrong:Designpossibleeffects.Productenduser.Localuser.Other,inbetweenusers.Processpossibleeffects.Theproducteffects.Processeffects.Detection,canitbedetectedifitgoeswrong.P-Typecontrols-Preventingitfromhappening.D-Typecontrols-Detectitifgoeswrong.,PotentialCauseofFailure,Listallpossibleconceivablecausesofeachfailuremode.Thelistshouldbecompleteaspossiblesothatcorrectiveactionscanbeimplementedeffectivelyandtimely.Itmustbeaprocessormanufacturingcause.Useasmuchdetailaspossibletodefinethecauseofthefailure.Consider:Method,machinery,materials,peopleandenvironment.,Effects,Aneffectofthefailuremodethatwouldbenoticedorexperiencedatthenextoperation,atasubsequentoperation,byanydownstreamuser.Consider:Nextuser.Ultimateuserorcustomer.Productoperation.Governmentregulations.,SeverityDefinition,Severityistheassessmentofthefailureeffectsontheprocessaswellastheproduct.Severityratingapplytotheeffectsandtheeffectsonly.Severityassessmentisfocusingonboththeprocess/operationandtheproduct.Allcausesofafailuremodehavingthesameeffectshouldbeassignedthesameseverityranking.Severityrankingscalegoesfrom1to10.,FailureModeSeverity(S),Severityisaratingcorrespondingtotheseriousnessoftheeffectofthepotentialfailuremode.SeverityDescription(1)Noeffectonthesystemperformance.(2)VeryslightEffect.Nuisancefaultnoticed.(3)SlightEffect.Nuisancefaultobvious.(4)MinorEffect.Chronicnuisancefault.(5)ModerateEffect.Nuisancerepairrequired.(6)SignificantEffect.Repairrequired.(7)MajorEffect.Rework/repairsrequired.(8)SeriousEffect.Equipment/verydissatisfiedcustomer.(9)VerySeriousEffect.Stopshiprequired.(10)HazardousEffect,suddenfailure,ornon-compliancetoregulationsorliabilityissue.,CurrentControls,Currentcontrolsareintendedtopreventthecauseofthefailurefromoccurring,todetectthecauseifitshouldoccur,andtoreducetheimpactsofthefailureeffects.Forexample:SPC.Fixturefoolproofing.ProcessDOE.SE.approval.Productionvalidation.Preventivemaintenanceprogram.GaugeR-Rstudy.Operatortraining.,OccurrenceDefinition,Theoccurrenceratingcorrespondingtotherateatwhichthecauseandtheresultingfailuremodewilloccuroverthelifeoftheproductandbeforeanyadditionalprocesscontrolsaredeveloped.Acauseofthefailuremodeisadeficiencythatresultsinafailuremode.Itisadescriptionofhowtheprocesscouldcauseafailuretooccur.Theoccurrencenumberhasmeaningratherthanvalue.Aratingscaleof1to10isused.,OccurrenceEvaluationStartingPointQuestions,Howlikelyisthecausetooccur?Howeffectivearethecurrentcontrols?Istheprocessstableormature?Howlargeisthechangefromthepreviousprocess?Isthepartanewdesign?Isthenewprocessnewtechnology?Designengineersexpectations?,FailureModeOccurrence(O),Detection,Detectionistheratingcorrespondingtotheprobabilitythatthecurrentprocesscontrolswilldetectthepotentialfailuremodebeforeitgetstothecustomer.Consider.Detectionshouldnotberelatedtotheoccurrence.Detectionindicatestheprobabilityofdetectingafailurethathasoccurred.Assumethefailurehasoccurredtodeterminethedetectionrating.,FailureModeDetection(D),Detectionisaratingcorrespondingtothetheabilityofthedetectionmethodtodetectthepotentialfailuremode.RatingDescription(1)Almostcertaintodetectfailuremode.(2)Veryhighchancefailuremodewillbedetected.(3)Highchancefailuremodewillbedetected.(4)Moderatelyhighchancefailuremodewillbedetected.(5)Mediumchancecontrolsmightdetectfailuremode.(6)Lowchancecontrolswilldetectfailuremode.(7)Slightchancecontrolswilldetectfailuremode.(8)Veryslightchancecontrolswilldetectthefailuremode.(9)Remotechancecontrolswilldetectthefailuremode.(10)Almostnochancecontrolswilldetectfailuremode.,FMEAScoreStandard,RiskPriorityNumber(RPN),TheRPNvalueisthemultiply-effectsofoccurrence,severity,anddetection.RPN=(S)x(O)x(D)RPNshouldbeconsideredasariskassessment.TheRPNvalueisaweightedassessmentnumberforprioritizingcorrectaction.,RiskPriorityNumbers(RPN),PrioritizedActions,Actionsshouldbetakenifseverityis8,9or10.Severityandoccurrenceproductishigh(49orgreater).High(RPN)number.RPN=SxOxD.Toreducetheseverity,occurrenceordetectionratings:Whatshouldonedo?Whichshouldbedonefirst.,PriorityofCorrectiveActions,Eliminatecausesoffailure.Reduceoccurrenceoffailures.Reduceeffectsoffailure.Firstreduceproducteffects.Secondreducelocalprocesseffects.Thirdreducedownstreameffects.Providetheresourcestoeliminatethefailuremodes.,Section4:DevelopmentofFMEA,PFMEADevelopment,TeamselectionProcessmap,determinefunctionsofprocessstepsDeterminefailuremodesIdentifyeffects,rateseverityIdentifycauses,rateoccurrenceIdentifycurrentcontrol,ratedetectionTakeaction,FMEADevelopmentProcess,MapProcess,DetermineFunctionsofProcessSteps,DetermineFailureModes,Multiply:SeverityTimesOccurrenceandRPN=OxSxD,ConstructParetoDiagram,SelectFailureModetoChange,UpdateDocumentReprioritize,IdentifyEffects,IdentifyCauses,RateSeverity,RateOccurrence,RateDetection,CollectDataPrioritizeCausesAffectImportantcausesVerifyImprovement,CollectDataMakeChangeVerifyImprovementImplementChange,A