FMEA-Eng-3-8-00

FMEAOutline•Section1:WhatisFMEA•Section2:FMEAPurpose•Section3:ElementaryConceptsofFMEA•Section4:DevelopmentofFMEA•Section5:ProcessFMEAApplicationExampleProcessPFMEAAnalysisSheetPFMEAProcessAnalyzed_________________FunctionPotentialEffectofSeverityCauseofOccurrenceCurrentDetectionRPNRecommendedFailureModeFailureFailureRateProcessActions(1-10)(1-10)Controls(1-10)Section1:WhatIsFMEAWhatisFMEA•FMEAistheprefixofPotentialFailureModeandEffectsAnalysis.Thewordpotentialisomitted.•FMEAisasystematicmethodwhichidentifiespotentialproductproblemsinthefollowingareas.–Productdesign.–Productmanufacture.–Productuse.•FMEAisdevelopedbyChrysler,Ford,GeneralMotors.•FMEAincludingDFMEA--DesignFMEA&PFMEA--ProcessFMEA.•BasedonSAEproductcharacteristic,wewillstudyPFMEAdetailedly.FMEAHistory•Mid-60’s:StartedintheAerospaceIndustries.•1974:NavycreatedFMEAStandard.•1976:USDepartmentofDefenseadoptedanFMEAstandard.•Late70’s:AutomotiveIndustriesstartedtouseFMEA.•Early80’s:MicroElectronicIndustrystartedtoapplyFMEAtoassistinimprovingthe“yieldofmemorydevices”.•Mid80’s:AutomotiveindustriesstartedtoapplyFMEAtothemanufacturingprocesses.•90’s:TQS9000recommendedadoptionofFMEA.Section2:FMEAPurposeFMEAPurpose•Controltool.–Designcontrol.–Manufacturingcontrol.•Riskanalysistool.•Managementtool.–Prioritizeproductimprovementactivity.–Continuousimprovementtool.Whatdowedonext?•Toreduceproductorserviceconcernsandtominimizetheprobabilityofdefectiveproductreachingthecustomer.•Toidentifypotentialfailuremodesandtoratetheseverityoftheireffects.•Toidentifythecriticalcharacteristicsoftheproductorprocess.•Toranktheorderofpotentialdesignandprocessdefects.FMEAPurposeFMEAapplicationinSAE•Nonconformingpreventionandcorrection•Failureanalysis•QCCtools,majorcauseconfirmation,actiontaking,andeffectcomparison•OthersengineeringareaSection3:ElementaryConceptsofFMEAFMEAConcepts•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)RankDescriptionFailureRateDPPM1Failuremodeunlikelytooccur.1in20,000502Remotechanceoffailure.1in10,0001003Relativelyfewfail