FMEA失效模式及其影响分析(ppt 63页).pptx

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1、1Describe FMEA principles and techniques. n描述描述FMEA的法则及技巧。的法则及技巧。Summarize the concepts, definitions, application options and relationships with other tools.摘要概念、定义、应用的选择和其他工具的关联。摘要概念、定义、应用的选择和其他工具的关联。Perform a FMEA执行一个执行一个FMEA。FMEA: Failure Modes and Effects AnalysisFMEA is a systematic approach us

2、ed to examine potential failures and prevent their occurrence. It enhances our ability to predict problems and provides a system of ranking, or prioritization, so the most likely failure modes can be addressed. FMEA是用来检查潜在失效和预防它再次发生的系统性方法.它增强了我们预测问题的能力,并提供了一个排序或区分优先次序的系统,因而使得最可能的失效模式得以确定.FMEA is gen

3、erally applied during the initial stages of a process or product design. Brainstorming is used to determine potential failure modes, their causes, their severity, and their likelihood of occurring. In Six Sigma, we apply FMEA to know failure modes. Our main interests are the cause and likelihood of

4、occurrence, for which we have actual data and do not need to rely on brainstorming.FMEA通常应用在工艺及产品设计的初期，自由讨论决定潜在失效的模式、原因、严重度及发生的可能性。在6S中，我们应用FMEA去了解失效的模式。我们主要感兴趣的是原因及发生的可能性。FMEA is also a valuable tool for managing tasks during defect/failure reduction projects.FMEA也是一个在失效缩小的管理任务的有价值的工具。1.recognize a

5、nd evaluate the potential failure modes and causes associated with the designing and manufacturing of a new product or a change to an existing product.2.认识和评估认识和评估新产品的设计和制造时或对现有产品做出改变时相关的潜在失效模式和原因2.identify actions which could eliminate or reduce the chance of the potential failure occurring,3.确定确定消

6、除或减少潜在失效发生机会的行动3.document the process.4.使过程形成使过程形成文件文件FMEA is a systematic design evaluation procedurewhose purpose is to: 是系统的设计评估程序是系统的设计评估程序Failure to perform a defined function执行既定功能的失效Something occurring that you dont expect, or want发生了你不希望或不想要的事情Wrong application应用错误lTo identify potential fail

7、ure modes and rate the severity of their effectslTo identify critical characteristics and significant characteristicslTo rank potential design and process deficiencieslTo help all of us focus on eliminating product and process concerns and prevent problems from recurringlReduce the product developme

8、nt timing and costDeveloped in early 60s by NASA to “fail-proof” Apollo missions.Adopted in early 70s by US Navy .By late 80s, automotive industry had implemented FMEA and began requiring suppliers do the same. Liability costs were the main driving force.Used sporadically throughout industry during

9、1980s.Adopted by MSI in ? Six Sigma is the catalyst.NASA used FMEA to identify Single Point Failures on Apollo project (SPF = no redundancy & loss of mission). How many did they find?420and we thought we had problems!SYSTEM DESIGNPROCESSSystem FMEA is used to analyze systems and subsystems in the ea

10、rly concept and design stages.Design FMEA is used to analyze products before they are released to productionProcess FMEA is used to analyze manufacturing, assembly and administrative processes“Do the best you can with what you have”AS EARLY AS POSSIBLE!Guideline:When new systems, products and proces

11、ses are being designedWhen existing designs and processes are being changedWhen carry-over designs or processes will be used in new applications or environmentsAfter completing a Problem Solving Study, to prevent recurrence of a problemSTARTCOMPLETESYSTEMAfter system functionsare defined, beforespec

12、ific hardware isselectedWhen the project isturned over to designDESIGNAfter product functionsand design concepts aredefined but before thedesign is completeWhen final drawingsare releasedPROCESSWhen preliminarydrawings are availablebut before tooling designis completedWhen the productreaches end of

13、life or isremoved fromproductionDesign StartDevelopmentProduction ReleaseProduction TimeNo of Engineering ChangesTraditional approachFMEA approachPotential Failure Mode and Effects Analysis PFMEA #: Process Responsibility: Prepared By: Process Name: Affected Products:#ProcessFunction(Step)Potential

14、FailureModes (ProcessDefects)PotentialEffects ofFailures (KPOVs)SEVPotential Causes ofFailures (KPIVs)OCCCurrentProcessControlsDETR P NRecommendActionsWhat is theprocess stepWhat is thekey processinputIn what waydoes the keyinput go wrongHow severe is the effect to customerWhat causes thekey input t

15、o gowrongHow often does cause occurWhat arethe existingcontrols &procedures(inspection& test) thatprevent withthe cause orFailureModeHow well can you detect cause ot FMWhat arethe actionsforreducingtheoccurrenceof theCause, orimprovingDetection?Should haveactions onlyon highRPNs oreasy fixes.CPotent

16、ialOProcessPotentialPotentialSlCause(s)cFailureEffect(s) ofeaMechanism(s)cFunction ModeFailurevsof FailureusrPoor training3Fail to detect in the process ofincoming inspection2Misunderstanding of defectdefinition2OP 100 INCOMINGINSPECTION -PORT FITTING/Toverify ports madeto printFail to identify dama

17、gedportPoor PrintbilityPoor gagePlacement Weldingprocess failureSealing processfailureFuction testin failure8Failure Mode Any way in which a process could fail to meet some measurable expectation.Effect Assuming a failure does occur, describe the effects. List separately each main effect on both a d

18、ownstream operation and the end user.Severity Using a scale provided, rate the seriousness of the effect. 10 represents worst case, 1 represents least severe.Causes This is the list of causes and/or potential causes of the failure mode.Occurrence This is a ranking, on a scale provided, of the likeli

19、hood of the failure occurring. 10 represents near certainty; 1 represents 6 sigma. In the case of a Six Sigma project, occurrence is generally derived from defect data.Current Controls All means of detecting the failure before product reaches the end user, are listed under current controls.Detection

20、 The effectiveness of each current control method is rated on a provided scale from 1 to 10. A 10 implies the control will not detect the presence of a failure; a 1 suggests detection is nearly certain.lThe potential failure mode is the manner in which the process could fail to perform its intended

21、function. lThe failure mode for a particular operation could be a cause in a subsequent (downstream) operation or an effect associated with a potential failure in a previous (upstream) operation. FAILUREMODEEFFECTPREVIOUSOPERATIONCAUSENEXTOPERATION Process FMEA considers process variability due to:O

22、PERATORSET-UPMACHINEMETHODENVIRONMENTMEASUREMENTuAssessment of the ability of the control to detect the failure before the item leaves the manufacturing area and ships to the customer.uCapability of all controls in the process to prevent escapesSPCProcess CapabilityGage R&RSamplingTestingDOESEVERITY

23、As it applies to the effects on the local system, next level, and end userOCCURRENCELikelihood that a specific cause will occur and result in a specific failure modeDETECTIONAbility of the current / proposed control mechanism to detect and identify the failure modeTypically, three items are scored:R

24、PN = O x S x D Occurrence x Severity x DetectionOSD xx= RPNA 8 4 3 96B 4 8 3 96SAME RESULTFailure ModeSeverityOccurrenceEffectivenessRPNEffectCriteria: Severity of Effect DefinedRankingHazardous:Without WarningMay endanger operator. Failure mode affects safe vehicle operation and / orinvolves noncom

25、pliance with government regulation. Failure will occur WITHOUTwarning.10Hazardous: WithWarningMay endanger operator. Failure mode affects safe vehicle operation and / orinvolves noncompliance with government regulation. Failure will occur WITHwarning.9Very HighMajor disruption to production line. 10

26、0% of product may have to be scrapped.Vehicle / item inoperable, loss of primary function. Customer very dissatisfied.8HighMinor disruption to production line. Product may have to be sorted and a portion(less than 100%) scrapped. Vehicle operable, but at a reduced level ofperformance. Customer dissa

27、tisfied.7ModerateMinor disruption to production line. A portion (less than 100%) may have to bescrapped (no sorting). Vehicle / item operable, but some comfort / convenienceitem(s) inoperable. Customers experience discomfort.6LowMinor disruption to production line. 100% of product may have to be rew

28、orked.Vehicle / item operable, but some comfort / convenience item(s) operable atreduced level of performance. Customer experiences some dissatisfaction.5Very LowMinor disruption to production line. The product may have to be sorted and aportion (less than 100%) reworked. Fit / finish / squeak / rat

29、tle item does notconform. Defect noticed by most customers.4MinorMinor disruption to production line. A portion (less than 100%) of the product mayhave to be reworked on-line but out-of-station. Fit / finish / squeak / rattle itemdoes not conform. Defect noticed by average customers.3Very MinorMinor

30、 disruption to production line. A portion (less than 100%) of the product mayhave to be reworked on-line but in-station. Fit / finish / squeak / rattle item doesnot conform. Defect noticed by discriminating customers.2NoneNo effect.1Probability of FailurePossible Failure RatesCpkRankingVery High:1 i

31、n 2 0.3310Failure is almost inevitable1 in 30.339High: Generally associated withprocesses similar to previous1 in 80.518processes that have often failed1 in 200.677Moderate: Generally associatedwith processes similar to1 in 800.836previous processes which have1 in 4001.005experienced occasional fail

32、ures,but not in major proportions1 in 2,0001.174Low: Isolated failures associatedwith similar processes1 in 15,0001.333Very Low: Only isolated failuresassociated with almost identicalprocesses1 in 150,0001.52Remote: Failure is unlikely. Nofailures ever associated withalmost identical processes1 in 1

33、,500,0001.671DetectionCriteria: Liklihood the existence of a defect will bedetected by test content before product advances tonext or subsequent processRankingAlmost ImpossibleTest content detects 80 % of failures10Very RemoteTest content must detect 80 % of failures9RemoteTest content must detect 8

34、2.5 % of failures8Very LowTest content must detect 85 % of failures7LowTest content must detect 87.5 % of failures6ModerateTest content must detect 90 % of failures5Moderately HighTest content must detect 92.5 % of failures4HighTest content must detect 95 % of failures3Very HighTest content must det

35、ect 97.5 % of failures2Almost CertainTest content must detect 99.5 % of failures1It is conducted on a timely basisandIt is applied by a product teamandIts results are documentedInvolve new technology Have changed from previous Are chronically in trouble Have a high degree of operator control Have a

36、high degree of variationChoose designs or processes which . . .Involve new technologyHave changed from previousAre chronically in troubleHave a high degree of operator controlHave a high degree of variationChoose designs or processes which.Manufacturing EngineerBuyerProcessOperatorProcess KnowledgeP

37、revious ExperiencePast ProblemsChronic ProblemsReliabilityEngineerProcess Functions, Potential Failure ModesEffects, Causes, Current ControlsAction PriorityActions to Eliminate or Reduce Failure ModeWarranty Claims1. Develop a StrategyS S T T 9 9 1 1 2 2 6 6 0 0 A AD D R R I IV V E EB B A A S S E E

38、S S U U B BS S Y Y S S T T E E M M & & F F I IR R M M W WA A R R E E C C O O V V E E R RM M E E D D I IA AD D I IS S C C P P A A C C K KF F I IN N A A L L A A R R M MA A R R M M S S U U B BA A R R M M C C O O I IL LB B O O B B B B I IN NR R O O T T . . A A R R M MS S P P . . F F L L E E X XS S P P I

39、 IN N D D L L E ES S T T A A T T O O R RR R O O T T O O R RH H D D A A A A S S S S E E M M B B L L Y YB B A A S S E E D D E E C C K KR R E E C C I IR R F F I IL L T T E E R RB B R R E E A A T T H H . . F F I IL L T T E E R RL L A A B B E E L L S SP P C C B B A A S S S S E E M M B B L L Y YD D I IS S

40、 C C C C L L A A M M P PB B A A L L . . W WT TS S P P A A C C E E R R S SM M A A G G A A S S S S Y YL L A A T T C C H HA A R R M M S S U U B BA A R R M M S S U U B BB B A A S S E E D D E E C C K KD D A A M M P P E E R RS S E E A A L LM M O O T T O O R R P P O O L L E E S S , , P P O O L L E E S S P

41、P A A C C E E R RTe a m s w ill b e e sta b lishe d to e va lua te the a p p lica tio n o f F M E A in a re a s sho w n b y the sha d ing o n the fo llo w ing d ia g ra m . E a ch F M E A Te a m und e r the d ire ctio n o f the F M E A F a cilita to r w ill:- E S TA B L IS H a stra te g y fo cusing

42、o n ne w te chno lo g y, p a st issue s, ne w o r re d e sig ne d co m p o ne nts, b o th fro m the p ro d uct (d e sig n) a nd p ro ce ss p e rsp e ctive s.- P R E P A R E a D e sig n a nd a P ro ce ss F M E A fo r the se le cte d co m p o ne nts o r sub a sse m b lie s.- D E TE R M IN E functio ns

43、, p o te ntia l fa ilure m o d e s, e ffe cts, ca use s, a nd ve rifica tio n a ctivitie s p la nne d o r in-p la ce . - R E C O M M E N D co rre ctive a ctio ns to the p ro d uct te a m .F IR S T P R IO R IT YS E C O N D P R IO R IT YT H IR D P R IO R IT Y1. Develop a Strategy2. Review the design /

44、process EFFECTCAUSES1. Develop a Strategy2. Review the design /process3. List functionsDevelop a StrategyReview the design/processList functions1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modesBasic Steps:1. Develop a strategy2. Review the desig

45、n/process3. List functions4. Brainstorm potential failure modes1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. Organize potential failure modestopictopicAffinity Diagram1. Develop a Strategy2. Review the design /process3. List functions4. Br

46、ainstorm potential failure modes5. Organize potential failure modes6. Analyze potential failure modes1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. Organize potential failure modes6. Analyze potential failure modes7. Establish risk priority

47、VITALFEWTRIVIALMANY1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. Organize potential failure modes6. Analyze potential failure modes7. Establish risk priority8. Take action to reduce risk1. Develop a Strategy2. Review the design /process3.

48、List functions4. Brainstorm potential failure modes5. Organize potential failure modes6. Analyze potential failure modes7. Establish risk priority8. Take action to reduce risk9. Calculate resulting RPNsO*S*D=RPN1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potentia

49、l failure modes5. Organize potential failure modes6. Analyze potential failure modes7. Establish risk priority8. Take action to reduce risk9. Calculate resulting RPNs10. Follow upIFTHENHOW DOI KNOW?CAUSEFAILURE MODEEFFECTThe design or process must be improved based on the results of the FMEA study.A

50、 well-developed FMEA will be of limited value without positive and effective corrective actions.Describe FMEA principles and techniques. Summarize the concepts, definitions, application options and relationships with other tools.Perform a FMEADescribe FMEA principles and techniques. Summarize the co