关于FMEA的培训资料(英文版)(ppt 24页).ppt

FailureMode EffectAnalysis ExplanationandUseofFMEA WhatisFMEA FMEAisaproblemsolvingprocessadoptedbySnap onasakeycomponentoftheQualityForwardSystem Generally FMEAisdonebyanon sitemultifunctionalteamfacilitatedlocallyorbyanSEQGroupAdvancedQualityEngineer Objectiveistoidentifyallofthereasonswhyqualityofaprocessorproductdoesnotmeetexpectations Usesseverity occurrenceanddetectionratingstodeterminecorrectiveactionpriorityforeachpossiblefailurereason WhenshouldaFMEAstudybeconducted AspartofaDesign Developmentphase Whencorrectiveactionisneededduetounfavorableperformancedata performancebasedonQFSmetricsdoesnotmeetgoals WhenaneedtomakeincrementalimprovementisidentifiedbyfacilitymanagementortheSEQGroup FMEATeamStart Up TeamSelection donebylocalqualitycoordinator businessunitmanageror onrequest SEQGroupAdvancedQualityEngineer ProblemStatement Aconciseandfocuseddescriptionofthequalityproblemoropportunityforimprovement whatwentwrong or whatneedsfixing GoalStatement adescriptionofwhatistobeaccomplishedbytheteam inquantifiableterms reduceby increaseby eliminate etc Goodmetricstouseincludescrapcost reworkcost orDefectsPerMillionOpportunities DPMO etc Forexample agoalstatementcouldbe ToreduceDPMOonproductfamilyXfrom3000to2000byyearend CompleteFMEATeamStart UpWorksheet examplelocatedinprocedureSEQ80 10 Figure1 ProblemStatement GoalStatement ProblemStatementandGoalStatementshouldconsider Whatwentwrong Whatisthegapbetweenthedesiredqualitylevelandtheactualqualitylevel Whichprocessorprocessesareinvolved Whichdepartmentorcellisthedeficiencyoccurringin Istheproblemcyclic canitbeattributedtospecificevents Whataretheappropriatemetricstomeasure Whatistheimpactonoperationalfitnessandprofitability Whatistheimpactonthebottomline reduced increased eliminated Arethereconstraintsrecognizedearlyintheprocess Ifso havetheybeenexploredandclarifiedwiththeappropriatemanagementlevel FMEAProcess FMEA suncoverprocessproblemsrelatedtothemanufactureofproduct Examples apieceofautomatedassemblyequipmentmaymisfeedpartsresultinginproductsnotbeingassembledcorrectly or inachemicalmanufacturingprocess temperatureormixingtimecouldbesourcesofpotentialfailuresresultinginunusableproduct Thinkintermsofthefiveelementsofaprocess people materials equipment methodsandenvironment Withthesefiveelementsinmind ask Howcanprocessfailureaffecttheproduct processingefficiencyorsafety NinestepsinFMEAprocess Step 1 ReviewtheProcess EnsurethateveryoneontheFMEAteamhasthesameunderstandingoftheprocessbeingworkedon Reviewblueprint engineeringdrawingofproduct ifconductingFMEAonproduct and oradetailedflowchartoftheprocess Ifthesearenotavailable theteamwillneedtocreateone Usingtheblueprintand orflowchart teammembersshouldfamiliarizethemselveswiththeproductorprocess Theyshouldphysicallyseetheproductoraprototypeoftheproduct andphysicallywalkthroughtheprocessexactlyastheprocessflows Itishelpfultohavean expert ontheproductorprocessavailabletoansweranyquestionstheteammighthave Step 2 BrainstormPotentialFailureModes Methodofgeneratinganddocumentingideasofpotentialfailuremodes Ifproductorprocessiscomplex aseriesofbrainstormingsessions eachfocusedonadifferentelement i e people methods equipment materials environment maybeneededtogenerateamorethoroughlistofpotentialfailuremodes Facilitatorshouldwritedownallideasgeneratedinbrainstormingsessions Oncebrainstormingiscomplete ideasshouldbegroupedintolikecategories asdeterminedbytheteam Groupscanbetypeoffailure whereontheproductfailureoccurred estimatedseriousnessofthefailure etc Failuremodesmayalsobecombinediftheyarethesameorverysimilar Oncefailuremodeshavebeengrouped combined theyshouldbetransferredtothePotentialFailureModeandEffectAnalysisSheet exampleinSEQ80 10 Figure2 Step 2 continued BrainstormingGuidelines Donotmakeanyjudgmentonideas Teammembersshouldnotcommentonwhetheranideaisgoodorbad Thinkingshouldbeunconventional imaginative orevenoutrageous Aimforalargenumberofideasintheshortestpossibletime Teammembersshould hitchhike onotherideas byexpandingthem modifyingthem orproducingnewonesbyassociation Allteammembersshouldparticipateinbrainstormingprocess Step 3 ListPotentialEffectsofEachFailureMode AfterthefailuremodesarelistedontheFMEAworksheetform theFMEAteamneedstorevieweachfailuremodeandidentifythepotentialeffectsofthefailureshoulditoccur Forsomefailuremodes theremaybeonlyoneeffect whileotherfailuremodesmayhaveseveraleffects Thisstepmustbethorough thisinformationwilldetermineassignmentofriskratingsforeachofthefailures Itishelpfultothinkofthisstepasanif thenprocess Ifthefailureoccurs thenwhataretheconsequences Step 4 AssignSeverityRating Theseverityratingisanestimateofhowserioustheeffectswouldbeifagivenfailuredidoccur Maybebasedonpastexperience oranestimatebasedontheknowledgeandexpertiseoftheteammembers Becauseeachfailuremayhaveseveraldifferenteffects andeacheffectmayhaveadifferentlevelofseverity theeffect notthefailure mustberated Eacheffectshouldbegivenitsownseverityrating Ratingsbasedon10 pointscale with1beingthelowestratingand10beingthehighest Generalexampleonnextpage maybecustomizedbyteamfortheirspecificFMEAproject Step 4continued SeverityRatingScaleExample Step 5 AssignOccurrenceRating Theoccurrenceratingisameasureofhowoftenanfailuremodemayoccur Bestmethodfordetermineoccurrenceratingistouseactualdatafromtheprocess forexample failurelogsorprocesscapabilitydata Ifactualdataisnotavailable theteamneedstoestimatehowoftenafailuremodecouldoccur Teamcanmakeabetterestimateofhowlikelyafailuremodeistooccurandatwhatfrequencybyknowingthepotentialcausesoffailure Ratingsbasedon10 pointscale with1beingthelowestratingand10beingthehighest Generalexampleonnextpage maybecustomizedbyteamfortheirspecificFMEAproject Step 5continued OccurrenceRatingScaleExample Step 6 AssignDetectionRating Thedetectionratinglooksathowlikelyitisthatafailureortheeffectofafailurewillbedetected Startbyidentifyingcurrentcontrolsthatmaydetectafailureoreffectofafailure example SPCorin processchecks Morecontrolsinplacegeneratesalownumber better rating nocurrentcontrolsmeansthelikelihoodofdetectionislowandthereforetheitemwouldreceiveahighnumber worse rating Ratingsbasedon10 pointscale with1beingthelowestratingand10beingthehighest Generalexampleonnextpage maybecustomizedbyteamfortheirspecificFMEAproject Step 6continued DetectionRatingScaleExample Step 7 CalculateRiskPriorityNumber Theriskprioritynumber RPN iscalculatedbymultiplyingtheseverityratingtimestheoccurrenceratingtimesthedetectionratingforalloftheitems RPN SeverityXOccurrenceXDetectionTotalRPNiscalculatedbyaddingalloftheRPNnumbers ThisnumberservesasarankingtooltoprioritizewhichFailureModesaretobeconsideredaconcernandthereforeshouldbeaddressedfirst Step 8 PrioritizetheFailureModesforAction OncetheRPNiscalculated thefailuremodescanbeprioritizedbyrankingtheminorderfromthehighestRPNtothesmallest AParetodiagramishelpfultovisualizethedifferencesbetweenthevariousratings Whenthefailuremodesareranked theteammustdecidewhichitemstoworkon Usuallyithelpstosetacut offRPN whereanyfailuremodewithanRPNabovethatpointrequiresaction Thosebelowthecut offareleft