FailureModesandEffectsAnalysis(FMEA)潛在失效模式及影響分析Introduction介紹

AprocesspotentialFMEAisananalyticaltechniqueutilizedbyamanufacturingresponsibleengineer/teamasameanstoassurethat,totheextentpossible,potentialfailuremodesandtheirassociatedcauses/mechanismshavebeenconsideredandtheengineer’s/team’sthoughts(includingananalysisofitemsthatcouldgowrongbasedonexperienceandpastconcerns)asaprocessisdeveloped.Thissystematicapproachparallelsandformalizesthementaldisciplinethatanengineernormallygoesthroughinanymanufacturingplanningprocess.過程的FMEA是負(fù)責(zé)制造生產(chǎn)的工程師/隊(duì)伍使用的分析技法，用來在一定程度上確保潛在的失效模式和相關(guān)的原因/機(jī)制都已考慮到，以及工程師/隊(duì)伍的想法（包括基于經(jīng)驗(yàn)和過去的想法得出的可能失效項(xiàng)目分析）。這種系統(tǒng)性的方法將工程師在任何生產(chǎn)計(jì)劃過程中通常會(huì)碰到的問題標(biāo)準(zhǔn)化了。2TheProcesspotentialFMEAIdentifiespotentialproductrelatedprocessfailuremodes.確認(rèn)與產(chǎn)品有關(guān)的過程失效模式Assessesthepotentialcustomereffectsofthefailures.評(píng)估失效對(duì)客戶潛在的影響Identifiesthepotentialmanufacturingofassemblyprocesscausesandidentifiesprocessvariablesonwhichtofocuscontrolsforoccurrencereductionordetectionofthefailureconditions.確定潛在的制造原因和過程變數(shù)，以便加以控制，減少發(fā)生可能性，增加發(fā)現(xiàn)到的可能性Developsarankedlistofpotentialfailuremodes,thusestablishingaprioritysystemforcorrectiveactionconsiderations.列出潛在失效模式的排行表，建立一個(gè)優(yōu)先系統(tǒng)以做出改善行動(dòng)Modifymanufacturingorassemblyprocess.

改變生產(chǎn)或生產(chǎn)線過程3FMEAStep步驟:

1.DefinethescopefortheFMEA定義FMEA的范圍2.Identifyteammembers,customer,andknowledgeexperts確認(rèn)隊(duì)伍成員、客戶，和專家3.Developrolesandresponsibilitiesforteammembers制定每個(gè)成員的任務(wù)和職責(zé)4.Studytheproduct/process/service研究產(chǎn)品/制程/服務(wù)5.Brainstormfailuremodes,knownandpotential集體討論已知的和潛在的失效模式6.Listtheeffects,causes,andcurrentcontrolsforeachfailuremode列出影響、原因和失效模式當(dāng)前控制情況7.AssignratingsforSeverity,Occurrence,andDetection給嚴(yán)重性、發(fā)生率、發(fā)現(xiàn)度的評(píng)分8.CalculateRPN計(jì)算RPN9.DecideonathresholdRPN制定采取行動(dòng)的RPN界限值10.PrioritizebasedonRPNandseverity,orasrequiredbythecustomer優(yōu)先性要根據(jù)RPN，嚴(yán)重性，或客戶的要求11.Identifycorrectiveactions確認(rèn)改善行動(dòng)12.Implementandverifyeffectivenessofcorrectiveaction執(zhí)行并確認(rèn)改善行動(dòng)的有效性13.Completethedocumentation完成文件記錄4DefinethescopefortheFMEA

定義FMEA的范圍Definetheboundarieswithinwhichtheproduct,process,orservicewillbestudied,identifyingtheoperatingassumptions,currentconditionsandconstraints.定義產(chǎn)品、制程或服務(wù)的研究范圍，確認(rèn)運(yùn)作前提，當(dāng)前條件和約束。52.Identifyteammembers,customer,andknowledgeexperts

確認(rèn)隊(duì)伍成員、客戶和專家

Gettheteamtogether,identifythecustomerandinvolvethemintheprocess.Somepreliminaryworkmustbedonetounderstandtheproduct/process/service,sotherightteamcanbeassembled.將成員集合，確認(rèn)客戶并使他們參與進(jìn)來。為了很好地理解產(chǎn)品/制程/服務(wù)，一些先前工作要做，已使小組集合起來。6

3.Developrolesandresponsibilitiesforteammembers

制定每個(gè)成員的任務(wù)和職責(zé)Whodoeswhatontheteam.Clearlydefinetherolesandresponsibilitiesforeachoftheteammembers.Atthistime,itisimportanttoconsiderthestrengthsofeachindividualandleveragethesame.誰做什么，清楚地定義每個(gè)成員的職責(zé)。這時(shí)，考慮每個(gè)人的長(zhǎng)處很重要。Example:TeamLeader:*Coordinatetheactivitiesoftheteam,andkeepontrack

例：隊(duì)長(zhǎng)協(xié)調(diào)隊(duì)伍的活動(dòng)，時(shí)時(shí)追蹤*Actascheerleader,andinterfacewithmanagement

充當(dāng)鼓舞者與管理相結(jié)合

*Ensurethedecisionsaremadewithconsensus

確保和大家一起做決定

Customer:*Definerequirements定義需求

客戶*Participateindevelopingratingscales,especiallyforSeverityKnowledge參與等級(jí)制定，尤其是嚴(yán)重性Expert:*Asconsultantprovideinfoondetailsofproduct/

專家

processorservice作為顧問提供產(chǎn)品等信息74.Studytheproduct/process/service

研究產(chǎn)品/制程/服務(wù)

Theobjectiveofthisstepistoacquireasmuchknowledgeaspossible.Itishighlyrecommendedthatallteammembersdelveintothis,sincethereisnootherwaytofamiliarizeyourselfwiththeproduct/process/service.此步驟的目的是為了盡可能多的獲取知識(shí)。高度建議所有成員都參與，因?yàn)闆]有其他的方式使你去熟悉產(chǎn)品/制程/服務(wù)。85.Brainstormfailuremodes,knownandpotential

集體討論已知的和潛在的失效模式*Failuremodesshouldbedescribedin“physical”ortechnicalterms,notasasymptomnoticeablebythecustomer.

失效模式應(yīng)描述為物理量或技術(shù)術(shù)語(yǔ)，而不是簡(jiǎn)單的表面現(xiàn)象 *Theideaistoidentifyasmanyfailuremodesaspossible.Thiswillinvolvegettingallteammembersandstakeholdersinvolved,however,theproperapproachtobrainstormingmustbeused.Deferalljudgment,maybeeventoasubsequentmeeting.確認(rèn)盡可能多的失效模式，使所有的成員都參與。使用適當(dāng)?shù)哪X力震蕩方法。所有的調(diào)節(jié)整理留給以后的會(huì)議。*Thebiggestriskinthisstepisthatparticipantswillstartmixingupfailuremodeswithcauses,andeffects.Topreventthis,itishighlyrecommendedthatmeetingleaderdoadryruntofamiliarizethegroupwiththedifferencesbetweenfailuremodes,effects,andcauses.Alistingoftheproduct/process/services’specifications,oroutputsandrequirementswillbenefithere.

最大的風(fēng)險(xiǎn)是參與者會(huì)混淆失效模式、原因和影響。建議會(huì)議領(lǐng)導(dǎo)者做個(gè)排練，使大家熟悉失效模式、原因和影響的差別。產(chǎn)品/制程/服務(wù)的規(guī)格，產(chǎn)出或需求會(huì)對(duì)此有所幫助。*Postitpadsareaconvenientwayofcollectingthisinformation,andgroupingitintologicalgroups.小紙貼是收集此種信息的有效途徑，然后按邏輯分組。*Ifyouwritetheseonaworksheet,makesureyouleaveenoughspaceforeffectsandcauses

如果你將此寫在工作紙上，要確保留出足夠的空間填寫影響和原因。95.Brainstormfailuremodes,knownandpotential

集體討論已知的和潛在的失效模式SeparatingFailureModes,EffectsandCauses分開失效模式，影響和原因Multiplicitywillexistforcauses,failuremodes,andeffects失效模式，影響和原因是多種多樣的FailureModes:Willsharecauses,andeffects失效模式：有共同的原因和影響Causes:Thereasonsforfailure,canbeoneormanyforagivenfailuremode原因：不良的原因可以是一個(gè)或多個(gè)已有的失效模式的原因Effects:Theresultsofthefailure,canbeoneormanyforagivenfailuremode影響：不良的結(jié)果可以是一個(gè)或多個(gè)已有的失效模式的結(jié)果Cause1Cause2FailureMode1Effect1FailureMode2Effect2106.Listtheeffects,causes,andcurrentcontrolsforeachfailuremode

列出影響、原因和失效模式的當(dāng)前控制情況

*Tocapturetheeffects,causes,andexistingcontrolsifanyforthefailuremodeinquestion.Inputfromcustomer,knowledgeexpertswillbeespeciallyhelpfulatthisstep.專家及客戶在失效模式的影響、原因，和當(dāng)前控制上尤其能提供幫助。*Caution:Manyteamscommiterrorsofwishfulthinkinghere,especiallywithregardtocurrentcontrols.Youshouldfocusonthecurrentstate,andnotonwhatcouldbedone,orwhatoughttobedone.

注意：許多成員由于打如意算盤而犯錯(cuò)誤，尤其對(duì)當(dāng)前的控制。我們應(yīng)該關(guān)注當(dāng)前的狀況，而不是關(guān)注應(yīng)該做的或可以做的。*Nowstartdocumentingontheworksheet,knowingthateachfailuremodecanhavemultipleeffects,andmultiplecauses.現(xiàn)在開始做文件整理，要意識(shí)到失效模式有很多的影響和原因。116.Listtheeffects,causes,andcurrentcontrolsforeachfailuremode

列出影響、原因和不良型號(hào)的當(dāng)前控制情況

Example舉例:Loadcapacitylisted列出載重能力Overloaded超載TempGageCoolingSystem制冷系統(tǒng)StrandedonRoad在路上擱淺Oveheats過熱Car汽車RPNDCurrentControls當(dāng)前控制OCause原因SEffect影響FailureMode失效模式ProductProcessorService產(chǎn)品制程或服務(wù)127.AssignratingsforSeverity,Occurrence,andDetection

給嚴(yán)重性、發(fā)生率、發(fā)現(xiàn)度評(píng)分

Hereweaccomplishtheconversionofeachofthesefactorsintoanumericalvalue.Dependingonthequalityoftheratingscalesthisstepcanbeveryeasyorsomewhatfrustrating.

這里我們將每個(gè)因素都轉(zhuǎn)換成相對(duì)應(yīng)的數(shù)值。根據(jù)質(zhì)量等級(jí)標(biāo)準(zhǔn)，這個(gè)步驟可以很簡(jiǎn)單或有點(diǎn)煩人。

Therewillbetimeswhentheteamwilldisagreeonthevaluesassignedtoaparticularcause,effect,orfailuremode.Ratherthanvoting,itisrecommendedthattheteamtrytoreachconsensus.Incaseofdisagreements,aknowledgeexpert’sopinioncanbeusedtoincreaseunderstanding,ormoredatacanbesought.Inanycasetheteam’sdecisionshouldprevail.對(duì)于任何一個(gè)原因、影響或失效模式的等級(jí)劃分，小組成員之間很多時(shí)候會(huì)意見相左，建議多收集數(shù)據(jù)，專家的意見也可以用以提高理解，達(dá)成共識(shí)。137.AssignratingsforSeverity,Occurrence,andDetection

給嚴(yán)重性、發(fā)生率、發(fā)現(xiàn)度評(píng)分

Example舉例:ProductProcessorService產(chǎn)品制程或服務(wù)FailureMode失效模式Effect影響SCause原因OCurrentControls當(dāng)前控制DRPNCar汽車Oveheats過熱StrandedonRoad在路上擱淺7CoolingSystem制冷系統(tǒng)3TempGage4Overloaded超載8Loadcapacitylisted列出栽重能力8148.CalculateRPN計(jì)算RPNSimplyassigningratingsforSeverity,Occurrence,andDetectiondoesn’thelpquantifytheriskintoasinglemeasurablevalue.Multiplyingtheratingscoresthusfillsthisgap.NotethatinthisapproachwehavemaintainedequalweightforeachofthethreeS,O,D給嚴(yán)重性、發(fā)生率、發(fā)現(xiàn)度評(píng)分并不能將風(fēng)險(xiǎn)變?yōu)橐粋€(gè)單一測(cè)量的數(shù)值，把三個(gè)分?jǐn)?shù)乘起來填進(jìn)RPN欄，注意三個(gè)單值的權(quán)重是一樣的。ProductProcessorService產(chǎn)品制程或服務(wù)FailureMode失效模式Effect影響SCause原因OCurrentControls當(dāng)前控制DRPNCar汽車Oveheats過熱StrandedonRoad在路上擱淺7CoolingSystem制冷系統(tǒng)3TempGage484Overloaded超載8Loadcapacitylisted列出栽重能力844815

9.DecideonathresholdRPN制定采取行動(dòng)的RPN界限值

Identifythefailuremodesyouwillchoosetoworkon.Itmaynotbepracticaltoaddressallofthem.Thiscriticalstepmustbeconductedwithcustomerinvolvement,andconsensusbuilding.

確認(rèn)你選擇需要采取行動(dòng)的失效模式。對(duì)所有的模式整改是不實(shí)際的，這個(gè)關(guān)鍵步驟需客戶參與

Manyteamsrunintodifficultieshere,especiallywhenthecustomerinsistsallitemsneedtobeaddressed.Itneedstobeunderstoodthatsomeelementofriskwillalwaysbepresent.Thequestionthereforeis“Whatlevelofriskisacceptable”?

許多小組都會(huì)在這碰到困難，尤其當(dāng)客戶要求所有的項(xiàng)目都要被討論。風(fēng)險(xiǎn)總是會(huì)存在的。問題是：“什么程度的風(fēng)險(xiǎn)可以接受？”

Someofthedifferentapproachesthathavebeenusedtodefinethethresholdare;ParetoAnalysis,Topcauseforeachfailuremode,etc.

一些不同的方法都已被用來定義界限：泊拉圖分析，最高分等等DocumentonFMEAstartupformtoindicatethiswasdiscussed,andagreementreachedonthethresholdvalue.

關(guān)于FMEA的討論要寫成文件，要在界限值上達(dá)成一致。16

9.DecideonathresholdRPN

制定采取行動(dòng)的RPN界限值

*DecideonathresholdRPN,withoutignoringhighseverityfailuremodes決定RPN的臨界點(diǎn)，不要忽略失效模式的高嚴(yán)重性ExampleusingParetoChart用Pareto圖表舉例:80%ofCumulativeRPNCumulativeRPNCurveL累積RPN曲線Cause原因CumulativeRPN累積RPN1710.PrioritizebasedonRPNandseverity,orasrequiredbythecustomer

優(yōu)先性要根據(jù)RPN，嚴(yán)重性，或客戶的要求

*Arriveattheorderinwhichyouwillstartaddressingthefailuremodesandcauseforcorrectiveaction.AlthoughRPNandseveritybasedprioritizationseemsthemostlogical,yourdecisiontoproceedmustbemadewithcustomerinput.

訂出你對(duì)于失效模式和原因整改的順序。雖然RPN和按先后次序的嚴(yán)重性很有邏輯性，你仍然要根據(jù)客戶的信息來決定。*Thisstepiseasilyaccomplishedbysortingthedata,indescendingorder.Youcandothiswithineachfailuremodetomaintaindataintegrity.這個(gè)步驟根據(jù)數(shù)據(jù)分類可以很容易按降序完成，。每一個(gè)失效模式都可以這樣做以保證數(shù)據(jù)的完整。*Documentationonworksheetisimportanttoensurethewholeteamisinsync.相關(guān)的文件很重要，可以確保整個(gè)隊(duì)伍工作的同步性。18ExampleofsortedworksheetbyRPNwithineachfailuremode失效模式用RPN排序的例子：10.PrioritizebasedonRPNandseverity,orasrequiredbythecustomer

優(yōu)先性要根據(jù)RPN，嚴(yán)重性，或客戶的要求

844TempGage3CoolingSystem制冷系統(tǒng)4488Loadcapacitlistedonsideofdoor在門邊列出載重能力8Overloaded超載7StrandedonRoad在路上擱淺Oveheats過熱Car汽車RPNDCurrentControls當(dāng)前控制OCause原因SEffect影響FailureMode失效模式ProductProcessorService產(chǎn)品制程或服務(wù)1911.Identifycorrectiveactions確認(rèn)改善措施

*Inthisstepyouidentifythecorrectiveactionsneededtoeliminate/controlthecauses,andreducetheriskleveltoorbelowtheagreeduponthreshold.這個(gè)步驟你要確認(rèn)消除/控制起因的整改方法，去減低風(fēng)險(xiǎn)等級(jí)或使之低于規(guī)定的界限。

*Therewillbetimeswhenyoucannotworkontherootcause;insuchcasethebestcourseofactionwillbeviaadditionofcontrols/adequatewarningdevices/mechanismsofimpendingfailure.Re-evaluatetheratingsforS,OandD,followedbyRPNcalculation.很多時(shí)候你不能找出根本原因；這時(shí)最好的方法就是對(duì)未解決的不良進(jìn)行額外的控制/足夠的提醒裝置。根據(jù)RPN計(jì)算結(jié)果，重新衡量S，O，D的等級(jí)劃分。*Discussionwiththecustomerisimportantagainsincethecorrectiveactionswillimpactthem.Knowledgeexpertsmayalsoprovidevaluableinputastowhatkindsofcorrectiveactionwillbebestsuitedforthegivencause/failuremode.整改會(huì)影響到客戶，因此和他們討論很重要。專家也應(yīng)提供有用的信息，提議什么樣的整改最適合現(xiàn)存的問題。*Finally,fromallpossiblecorrectiveactions,theteammaychooseonebasedoncost/benefitanalysis,speedofimplementation,andthenewlevelofrisk.最后，對(duì)所有可能的改善行動(dòng)，小組可以成本/效益分析，執(zhí)行快慢，及新的風(fēng)險(xiǎn)等級(jí)選擇其中一個(gè)行動(dòng)計(jì)劃2011.Identifycorrectiveactions確認(rèn)整改Example舉例:10FebAllTraininadvanceddrivingtechniques提高駕駛技巧3505ABSandtractioncontrolABS和牽引控制7Drivinghabit駕駛習(xí)慣30MarRobertTakeupmatterwithcity與城市聯(lián)系3505Listentoforecasts聽預(yù)報(bào)7Slickroads潮濕的路10Accident-injury事故受傷Skids剎車None無844Tempgage3CoolingSystem制冷系統(tǒng)22JanJohnInstallloadcapacitysignseasilyvisibletodriver在司機(jī)容易看到的地方粘貼載重能力4488LoadCapacitylistedonsideofdoor在門邊列出載重能力8Overloaded超載7Strandedonroad在路上擱淺Overheats過熱Car汽車RPNDOSCompDate日期AssignedTo負(fù)責(zé)人CorrectiveAction整改RPNDCurrentControls當(dāng)前控制OCause原因SEffect影響FailureMode失效模式Product/Process/Service產(chǎn)品/制程/服務(wù)2112.Implementandverifytheeffectivenessofcorrectiveaction

執(zhí)行并確認(rèn)整改的有效性

*Correctiveactionsidentifiedoughttobeimplementedlikeprojects-withadefinitestartandend.Inmanycasesaprojectteamsmaybeformedtocarryouttheimplementation.TheseprojectteamsmayhavemembersfromoutsidetheFMEAteam,howeveratleastonemembershouldbedrawnfromtheFMEAteam.確認(rèn)整改方案應(yīng)該象完成一個(gè)項(xiàng)目-有明確的開頭和結(jié)尾。很多時(shí)候一個(gè)項(xiàng)目組都已形成以完成方案。這些項(xiàng)目組可以擁有FMEA小組外的成員，至少需有一個(gè)屬于FMEA的成員。*Acheckontheeffectivenessofthecorrectiveactionisimportant,intheabsenceofwhichyouwillnothaveacloseloopfeedbackonwhatreallytranspired.ThischeckshouldbeconductedbytheFMEAteamafterthecorrectiveactionshavebeeninplaceforsometime.Thisisbecausethecorrectiveaction,likeachange,maynotlast.Ittakesdiligentefforttoensurethechangewillhavepermanence.檢查整改是否有效很重要，否則你不能得知實(shí)際情況。檢查須在整改進(jìn)行了一段時(shí)間后由FMEA成員執(zhí)行。因?yàn)檎牟⒉皇亲罱K結(jié)果。需要努力才能確認(rèn)這個(gè)改變是否永久。*Ifthecorrectiveactionisnoteffectiveenough,youmayneedtoimplementsomemorecontrols/takemoreaction.如果整改沒有效，需要進(jìn)行更多的控制/行動(dòng)。22Example舉例:12.Implementandverifytheeffectivenessofcorrectiveac