10 Steps to Conduct a PFMEA(创建 FMEA 权威 步骤 )

第1页共8页10StepstoConductaPFMEAStep1Reviewtheprocess—Useaprocessflowcharttoidentifyeachprocesscomponent.Step2Brainstormpotentialfailuremodes—Reviewexistingdocumentationanddataforclues.Step3Listpotentialeffectsoffailure—Theremaybemorethanoneforeachfailure.Step4AssignSeverityrankings—Basedontheseverityoftheconsequencesoffailure.Step5AssignOccurrencerankings—Basedonhowfrequentlythecauseofthefailureislikelytooccur.Step6AssignDetectionrankings—Basedonthechancesthefailurewillbedetectedpriortothecustomerfindingit.Step7CalculatetheRPN—SeverityXOccurrenceXDetection.Step8Developtheactionplan—Definewhowilldowhatbywhen.Step9Takeaction—ImplementtheimprovementsidentifiedbyyourPFMEAteam.Step10CalculatetheresultingRPN—Re-evaluateeachofthepotentialfailuresonceimprovementshavebeenmadeanddeterminetheimpactoftheimprovements.第2页共8页Step1:ReviewtheProcessReviewtheprocesscomponentsandtheintendedfunctionorfunctionsofthosecomponents.Useofadetailedflowchartoftheprocessoratraveler(orrouter)isagoodstartingpointforreviewingtheprocess.ThereareseveralreasonsforreviewingtheprocessFirst,thereviewhelpsassurethatallteammembersarefamiliarwiththeprocess.Thisisespeciallyimportantifyouhaveteammemberswhodonotworkontheprocessonadailybasis.Thesecondreasonforreviewingtheprocessistoidentifyeachofthemaincomponentsoftheprocessanddeterminethefunctionorfunctionsofeachofthosecomponents.Finally,thisreviewstepwillhelpassurethatyouarestudyingallcomponentsoftheprocesswiththePFMEA.Usingtheprocessflowchart,labeleachcomponentwithasequentialreferencenumber.ThesereferencenumberswillbeusedthroughouttheFMEAprocess.Themarked-upflowchartwillgiveyouapowerfulvisualtorefertothroughoutthePFMEA.Withtheprocessflowchartinhand,thePFMEAteammembersshouldfamiliarizethemselveswiththeprocessbyphysicallywalkingthroughtheprocess.Thisisthetimetoassureeveryoneontheteamunderstandsthebasicprocessflowandtheworkingsoftheprocesscomponents.Foreachcomponent,listitsintendedfunctionorfunctions.Thefunctionofthecomponentisthevalue-addingrolethatcomponentperformsorprovides.Manycomponentshavemorethanonefunction.Step2:BrainstormPotentialFailureModesInStep2,considerthepotentialfailuremodesforeachcomponentanditscorrespondingfunction.第3页共8页Apotentialfailuremoderepresentsanymannerinwhichthecomponentorprocessstepcouldfailtoperformitsintendedfunctionorfunctions.UsingthelistofcomponentsandrelatedfunctionsgeneratedinStep1,asateam,brainstormthepotentialfailuremodesforeachfunction.Don’ttakeshortcutshere;thisisthetimetobethorough.Prepareforthebrainstormingsession.Beforeyoubeginthebrainstormingsession,reviewdocumentationforcluesaboutpotentialfailuremodes.Step3:ListPotentialEffectsofFailureDeterminetheeffectsassociatedwitheachfailuremode.Theeffectisrelateddirectlytotheabilityofthatspecificcomponenttoperformitsintendedfunction.Aneffectistheimpactafailurecouldmakeifitoccurred.Somefailureswillhaveaneffectonthecustomersandothersontheenvironment,thefacility,andeventheprocessitself.Aswithfailuremodes,usedescriptiveanddetailedtermstodefineeffects.Theeffectshouldbestatedintermsmeaningfultoproductorsystemperformance.Iftheeffectsaredefinedingeneralterms,itwillbedifficulttoidentify(andreduce)truepotentialrisks.Step4:AssignSeverityRankingsAssignaseverityrankingtoeacheffectthathasbeenidentified.Theseverityrankingisanestimateofhowseriousaneffectwouldbeshoulditoccur.Todeterminetheseverity,considertheimpacttheeffectwouldhaveonthecustomer,ondownstreamoperations,orontheemployeesoperatingtheprocess.第4页共8页Theseverityrankingisbasedonarelativescalerangingfrom1to10.A“10”meanstheeffecthasadangerouslyhighseverityleadingtoahazardwithoutwarning.Conversely,aseverityrankingof“1”meanstheseverityisextremelylow.Therankingscales(forseverity,occurrence,anddetection)aremissioncriticalforthesuccessofaPFMEAbecausetheyestablishthebasisfordeterminingriskofonefailuremodeandeffectrelativetoanother.ThesamerankingscalesforPFMEAsshouldbeusedconsistentlythroughoutyourorganization.ThiswillmakeitpossibletocomparetheRPNsfromdifferentFMEAstooneanother.SeeFMEAChecklistsandFormsforanexamplePFMEASeverityRankingScale.Thebestwaytocustomizearankingscaleistostartwithastandard,genericscaleandthenmodifyittobemoremeaningfultoyourorganization.Asyouaddexamplesspecifictoyourorganization,consideraddingseveralcolumnswitheachcolumnfocusedonatopic.Onetopiccouldprovidedescriptionsofseveritylevelsforoperationalfailures,anothercolumnforcustomersatisfactionfailures,andathirdforenvironmental,health,andsafetyissues.SeeFMEAChecklistsandFormsforanexamplesofCustomPFMEARankingScales.(Examplesofcustomscalesforseverity,occurrence,anddetectionrankingsareincludedinthisAppendix.)Step5:AssignOccurrenceRankingsNext,considerthepotentialcauseorfailuremechanismforeachfailuremode;thenassignanoccurrencerankingtoeachofthosecausesorfailuremechanisms.Weneedtoknowthepotentialcausetodeterminetheoccurrencerankingbecause,justliketheseverityrankingisdrivenbytheeffect,theoccurrencerankingisafunctionofthecause.Theoccurrencerankingisbasedonthelikelihood,orfrequency,thatthecause(