FMEA-失效模式分析概述.pptx
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FMEA-失效模式分析概述.pptx
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1,AnanalyticaltoolforidentifyingPotentialFailuresinaproductorprocesssothatcorrectiveactioncanbetakenbeforethefailurescanreachthecustomer.,FMEA是一種識別產品或過程的潛在失效,以便在這些失效影響客戶之前採取措施的分析工具,2,AnFMEAisaStructuredApproachto:
FMEA是結構式的方法,Identifyingthewaysinwhichadesignorprocesscanfailtomeetthecriticalcustomerrequirements識別設計或過程可能以何種方式失效而不能滿足客戶重要需求Estimatingtheriskofspecificcauseswithregardtothesefailures估計產生這些失效的特殊原因的風險Evaluatingthecurrentcontrolsforpreventingthesefailures評估現有控制手段對這些失效的預防Prioritizingtheactionsthatmustbetakentoimprovethedesignortheprocess給那些用以改進設計和過程的措施排序,3,FMEAHistory歷史,Firstusedinthe1960sduringtheApolloMoonMissions.最早被用於上世紀六十年代的阿波羅登月計劃.In1974MIL-STD-1629wasdevelopedbytheNavyforusingFMEAs.1974年海軍為FMEA的應用制定了MIL-STD-1629.Inthelate1970,adaptedbytheautoindustryinresponsetohigherliabilitycostsandhigherqualitydemandsbycustomers.在二十世紀七十年代末,為滿足客戶更高的責任成本和質量需求而被用於自動化工業中.,4,FMEAisproactive,notreactive.Dontwaitforthecustomertocomplainifyoucanavoidit!
FMEA是預防性的,不是反應性的。
應當儘量避免失效,而不是等著顧客提出申訴!
5,FMEAreducesthechancethatacustomerwillseeafailureFMEA通過以下措施減少顧客遇到失效的情況:
Bydefiningfailureintermsofwhatthecustomerwantsandexpects.針對顧客的要求和期望確定失效Byshowingwheremeasuresneedtobetakentopreventfailure.指出爲了防止失效,需要在哪方面採取措施,6,TypesofFMEAs類型,Designusedtoanalyzeproductdesignsbeforetheyarereleasedtoproduction設計-用於在產品投產前對設計的分析Processusedtoanalyzemanufacturingprocesses過程-用於分析製程Systemusedtoanalyzesystemsintheearlyconceptanddesignstages系統用於分析早期的概念和設計階段的系統,7,Summary概要,Identifiesknownandpotentialfailuremodes;識別已知和潛在的失效模式Identifiesthecausesandeffectsofeachfailuremode;識別每一種失效模式的原因和後果Prioritizesthefailuremodes(usingtheRPN);利用風險序數(RPN)給失效模式排序Shouldinitiatecorrectiveactionwhereneeded.必要時提出糾正措施,8,TimingofanFMEAFMEA的時機,FMEAsshouldbeinitiatedwhenpreliminarydrawingsofthedesignorprocessareavailable當初步的設計圖紙和工藝被制定出來時應開始做FMEAUpdatedasidentifiedissuesareresolved當被發現的問題解決後要更新FMEACanbeusedonexistingproductstoimprovequality可用於現有的產品以提高質量,9,System系統Wiringharness線束Electronicmodule電控模塊Assembly總成,SystemFMEAtreatssystemasa“functionalschematic”系統FMEA從“功能關係圖”入手來考慮,SFMEA,10,Ananalyticaltoolusedtoidentifysystem-levelfailuremodes,andidentifycorrectiveactionstobetaken.是一種分析工具用來識別系統失效模式,11,ItissimilartoaDesignFMEA,butfocusesonthecircuitschematicinsteadofphysicalfailureofcomponents.同DFMEA相類似,系統FMEA側重於回路設計而不是元件的物理失效。
12,Example:
舉例:
Failuremodeatelectricalsystemlevel電氣系統失效模式OpencircuitatcktA回路A出現開路Cause:
原因:
Terminalunseated端子脫出Terminalunseatedbecomesafailuremodeatthecomponentlevel.端子脫出是電氣元件的失效模式。
13,RulesofDesignFMEA設計FMEA規則,Toolfordesignengineersandprojectteamtoimprovethedesigninapreemptivemanner(beforefailureoccur)是設計工程師和項目小組的工具用來提高設計的前瞻性(在問題發生前)UsedtoestablishedCriticaltoQualityfeaturesthateffecttheperformanceoftheproduct用與那些影響產品性能的重要質量特性UsedtoestablishCriticaltoLifefeaturesthateffectthelifeoftheproduct用於確定影響產品壽命的重要壽命特性UsedtoestablishCriticaltosafetyfeatures用於確定重要安全特性,14,PurposeofDesignFMEA設計FMEA的用途,Establishescriticalfeaturesthatmustbecontrolledinmanufacturingtosatisfycustomerrequirements確定那些必須在生產中進行控制的特性以滿足客戶要求Identifiesdeficienciesintheproductdesignandassociatedactionitems找出產品設計中的不足和相應的措施Helpsevaluatetheriskofdesignchanges幫助評價設計變更的風險,15,PurposeofDesignFMEA設計FMEA的用途,Identifiesprocessdevelopmentneeds確定開發工藝流程的需求Dynamicdocumentdocumentsdesignalternativesandassociatedrisks動態的文件記錄可選擇的設計方案和相應的風險Establishesbasesformanufacturingandqualitycontrolplan建立製造和品質控制計劃的基礎,16,DesignFMEAInputsandOutputs設計FMEA的輸入和輸出,Productdrawings產品圖紙Productmodels產品模型Productspecification產品規格,IdentifiedCriticaltoQualityfailures確定的重要質量特性Actionstopreventthecausesoffailures防止失效原因的措施Actionstodetectfailuremodes發現失效模式的措施HistoryofactionsandResponsibilities措施和責任人的記錄,17,Design设计Components元件Elements设计要素,DesignFMEAlooksatphysicalfailuremodesofcomponentsanddesignelements设计FMEA着眼于元件及设计要素的物理失效模式,DFMEA,18,RulesofProcessFMEA過程FMEA規則,Toolforprocessengineersandprojectteamtoimprovethemanufacturingprocessinapreemptivemanner是工藝工程師和項目小組的工具,用來提高製造工藝的前瞻性Usedtoprioritizeactionstoensureattentiontocriticalprocessesthateffectcustomers用與區分先後順序以確保那些影響客戶的重要工藝Usedtodocumentprocessimprovements用於工藝改進Dynamicdocumentforcontinuousimprovement持續改進的動態文件,19,PurposeofProcessFMEA過程FMEA的用途,Assistsintheanalysisofnewmanufacturingprocess幫助分析新的製造工藝Establishesthebasesformanufacturingprocessinstructionsandcontrolsheets建立製造工藝文件和控制文件的基礎Identifiesnewmanufacturingprocessneeds確定新製造工藝的需求Helpsevaluatetheriskofprocesschanges幫助評估工藝更改的風險,20,Process过程Manufacturing制造Assembling装配,ProcessFMEAlooksatproductfailurescausedbytheprocessfailingtomeetrequirements过程FMEA着眼于因加工過程不符合要求所造成的产品失效,PFMEA,21,FMEATeam小組,Teamapproachisnecessary.需要團隊的方式ResponsibleforDesignFMEADesignEngineer設計工程師負責設計FMEAResponsibleforProcessFMEAManufacturingEngineer製造工程師負責過程FMEARecommendedrepresentatives:
推薦人選:
Design/設計ManufacturingEngineers/製造工程師QualityEngineers/質量工程師Reliability/可靠性Materials/原材料Suppliers/供應商,22,DefinitionofTerms術語,FailureModeThewayinwhichaspecificinputrequirementfailsandifnotdetected,correctedorremovedwillcauseanEffecttooccur.失效模式一個特殊的輸入要求失敗的方式或者由於未被發覺,糾正或消除而帶來的後果EffectImpactoncustomerrequirements後果對客戶要求的影響,23,DefinitionofTerms術語,CauseSource(s)ofprocessvariationthatcausestheFailureModetooccur.原因造成失效模式發生的過程變差的起源CurrentControl(proposedcontrols)當前的控制(建議的控制)Designelementsthatensurefunction確保功能的設計要素Mistakeproofing,automatedcontrols,setupinstructions,gauges防錯,自動化控制,機器設定指導書,量具Audits,checklists,inspections,PM,etc.稽核,檢查表,檢驗,設備維護,等,24,LinkingFailureModestoEffects失效模式和後果之間的聯繫,FailureMode1,FailureMode2,Effect1,FailureMode1,Effect2,Effect1,FailureMode1,FailureMode2,Effect1,NotethattherelationshipbetweentheFailureModeandEffectisnotalways1-to-1請注意失效模式和後果之間的關係不總是一對一,Effect2,25,RiskPriorityNumber風險序數,TheoutputofaFMEAisthe“RiskofPriorityNumber”-RPN一個FMEA的輸出是“風險序數”-RPNTheRPNisacalculatednumberbasedoninformationprovidedregardingRPN是根據下面的資料計算出來的Thepotentialfailuremodes,潛在失效模式Theeffects,and後果Thecurrentorplannedabilitytodetectthefailurebeforeitreachesthecustomer現有的和已計劃的能力可以在影響客戶前覺察失效,26,RiskPriorityNumber風險序數,Itiscalculatedastheproductofthreequantitativerating它是用三個級數計算出來的RPN=Severity*Occurrence*Detection風險序數=嚴重度*發生頻度*探測度TheRPNisnotsacredRPN不是神聖的ScalingforSeverity,Occurrence,andDetectionarelocallydeveloped嚴重度,發生頻度,探測度的尺度由自己制定Othercategoriesmaybeaddedtosuitneed根據需要可以加上其他類型HighRiskPriorityNumbersaresignificanttothesuccessoftheproductdesign-actionsmustbetakentopreventfailures高風險序數對產品設計的成功來講很重要-需要採取措施來防止失效,27,DefinitionofRPNTermsRPN術語,Severity(ofeffect)Importancetocustomer,mayinvolvefunction,safety,reliability,orlifeofproduct(1=notsevere,10=verysevere)嚴重度(後果的)對客戶的重要程度,可包括功能,安全,可靠性,產品壽命等方面.(1=不嚴重,10=很嚴重)Occurrence(ofcause)FrequencywithwhichagivenCausemayoccur(1=notlikelytooccur,10=verylikelytooccur)發生頻度(原因的)一個特定的原因可能發生的頻度(1=不可能發生,10=很可能發生)Detection(CapabilityofcurrentorplannedControls)Abilitytodetectthecause(1=likelytobedetected,10=notlikelytobedetected)探測度(現有的或已計劃的控制能力)覺察原因的能力(1=有可能發覺,10=不可能發覺),28,RatingScales評分尺度,29,RatingScales評分尺度,30,RatingScales評分尺度,31,ExamplesofOccurrencescale發生率評分的例子,32,ExamplesofDetectionscale探測度評分的例子,33,Whatistheinput?
輸入是甚麼?
Whatcangowrongwiththeinput?
輸入會出甚麼錯?
WhatistheEffectontheoutput?
輸出的後果是甚麼?
Whatarethecauses?
原因是甚麼?
Howwell?
程度如何?
Howcanthisbefound?
怎樣才可以發現?
Howoften?
頻繁程度,Whatcanbedone?
可以做甚麼?
Howwell?
程度如何?
34,35,FMEAModel模式,Prevention/預防,Prevention/預防,Prevention/預防,Cause/原因,Effect/後果,FailureMode/失效模式,Controls/控制,Materialorprocessinput/原料或過程輸入,ProcessStep/工序,Externalcustomerordownstreamprocessstep/外部客戶或下一工序,36,GeneralStepsintheDFMEA/一般步驟,SelectdesignFMEAteam組建設計FMEA小組Listcustomerrequirements列出客戶的要求Foreachcustomerrequirementlistthekeydesignelementsthatsatisfythecustomerrequirements針對客戶的每一個要求列出滿足該要求的關鍵設計要素Foreachkeydesignelementlistwaysthatthedesignelementcouldvary,PotentialFailureModes列出每一個關鍵設計要素的變化,潛在的失效模式ListEffectsofeachFailuremodeonthecustomerrequirement列出每個失效模式的對客戶要求的影響ListCausesforeachfailureMode列出失效模式的原因,37,GeneralStepsintheDFMEA/一般步驟,Listcurrentcontrolsforeachcause列出每個原因的現有控制手段AssignSeverity,Occurrence,andDetectionratingstoeachcause給每個原因的嚴重度,頻度,可探測度評分CalculateRPNs計算風險序數RecommendactionstoreducehighRPNs提出降低風險序數的措施Takeappropriateaction採取適當的措施RecalculateRPNs重新計算風險序數,38,Aschematicrepresentation,with一種圖示法,其中Components(orfeatures)shownasblocks,用方塊表示各元件(或特性)Interactionsbetweencomponentsshownaslines,用直線表示各元件之間的關係Attheappropriatelevelofdetail詳細到恰當的程度,DevelopaFunctionalBlockDiagramofTheProduct繪制產品功能結構圖,39,BlockDiagram結構圖,Examples例如,40,Dontforgetauxiliaryfunctionsaswellaprimaryfunctions主要功能和輔助功能都要考慮Often,componentsworktogethertoperformafunction經常是幾個零件共同實現一個功能Hint:
UsetheBlockDiagram!
提示:
利用結構圖,ListTheFunction(s)ofEachComponent列出每個要素的功能,41,Adefect,flaw,orotherunsatisfactoryconditionintheproductthatiscausedbyadesignweakness由於設計缺陷造成的產品缺陷,瑕疵或其它令人不滿意的情況,TypicalFailureModes:
典型的失效模式-Breaks-Cracks破碎裂紋-Corrodes-Sticks腐蝕粘結-Deforms/melts變形/熔化,42,Startwiththeprevioustwosteps:
從前両個步驟入手:
Functions功能Qualityrequirements質量要求,43,Inyourowndescriptivewords,writedownthefollowingscenarios,用自己的語言描述下列假設:
Failure=Nofunction,失效=無功能Failure=Notenoughfunction,失效=功能不足Failure=Toomuchfunction,失效=功能過強Similarly,同樣:
Failure=Noqu
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