FMEA失效模式及其影响分析(2)

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。2FMEA: Failure Modes and Effects AnalysisFMEA is a systematic approach u

2、sed 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 ge

3、nerally 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。31.recognize

5、 and 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

6、定消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4Failure 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5lTo identify potential

7、failure 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 devel

8、opment timing and cost6Developed 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 du

9、ring 1980s.Adopted by MSI in ? Six Sigma is the catalyst.7NASA 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!8SYSTEM DESIGNPROCESSSystem FMEA is used to analyze systems and subsystem

10、s in the early 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 processes9“Do the best you can with what you have”AS EARLY AS POSSIBLE!Guideline:10When new systems, produ

11、cts and processes 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 problem11STARTCOMPLETESYSTEMAfter system functionsare def

12、ined, beforespecific 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 produc

13、treaches end of life or isremoved fromproduction12Design StartDevelopmentProduction ReleaseProduction TimeNo of Engineering ChangesTraditional approachFMEA approach13Potential Failure Mode and Effects Analysis PFMEA #: Process Responsibility: Prepared By: Process Name: Affected Products:#ProcessFunc

14、tion(Step)Potential 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 c

15、auses thekey input to 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 h

16、ighRPNs oreasy fixes.14CPotentialOProcessPotentialPotentialSlCause(s)cFailureEffect(s) ofeaMechanism(s)cFunction ModeFailurevsof FailureusrPoor training3Fail to detect in the process ofincoming inspection2Misunderstanding of defectdefinition2OP 100 INCOMINGINSPECTION -PORT FITTING/Toverify ports mad

17、eto printFail to identify damagedportPoor PrintbilityPoor gagePlacement Weldingprocess failureSealing processfailureFuction testin failure815Failure Mode Any way in which a process could fail to meet some measurable expectation.Effect Assuming a failure does occur, describe the effects. List separat

18、ely each main effect on both a downstream 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

19、 a scale provided, of the likelihood 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

20、under current controls.Detection 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.16lThe potential failure mode is the manner in which the process c

21、ould fail to perform its intended 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. FAILUREMODEEFFECTPREVIOUSOPERATIONCAUSENEXTOPERATION17 Process FMEA co

22、nsiders process variability due to:OPERATORSET-UPMACHINEMETHODENVIRONMENTMEASUREMENT18uAssessment 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 Capabi

23、lityGage R&RSamplingTestingDOE19SEVERITYAs 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 fai

24、lure modeTypically, three items are scored:20RPN = O x S x D Occurrence x Severity x DetectionOSD xx= RPN21A 8 4 3 96B 4 8 3 96SAME RESULTFailure ModeSeverityOccurrenceEffectivenessRPN22EffectCriteria: Severity of Effect DefinedRankingHazardous:Without WarningMay endanger operator. Failure mode affe

25、cts safe vehicle operation and / orinvolves noncompliance 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

26、.9Very HighMajor disruption to production line. 100% 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, bu

27、t at a reduced level ofperformance. Customer dissatisfied.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 p

28、roduction line. 100% of product may have to be reworked.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 (les

29、s than 100%) reworked. Fit / finish / squeak / rattle 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. De

30、fect noticed by average customers.3Very MinorMinor 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.123Probability of

31、FailurePossible Failure RatesCpkRankingVery High:1 in 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 processe

32、s which have1 in 4001.005experienced occasional failures,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

33、ever associated withalmost identical processes1 in 1,500,0001.67124DetectionCriteria: 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 de

34、tect 80 % of failures9RemoteTest content must detect 82.5 % 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

35、detect 95 % of failures3Very HighTest content must detect 97.5 % of failures2Almost CertainTest content must detect 99.5 % of failures125It is conducted on a timely basisandIt is applied by a product teamandIts results are documented26Involve new technology Have changed from previous Are chronically

36、 in trouble Have a high degree of operator control Have a 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.27

37、Manufacturing EngineerBuyerProcessOperatorProcess KnowledgePrevious ExperiencePast ProblemsChronic ProblemsReliabilityEngineerProcess Functions, Potential Failure ModesEffects, Causes, Current ControlsAction PriorityActions to Eliminate or Reduce Failure ModeWarranty Claims281. Develop a StrategyS S

38、 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 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

39、 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 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

40、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 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

41、 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 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

42、M E A F a cilita to r w ill:- E S TA B L IS H a stra te g y fo cusing 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

43、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, 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

44、 IT YT H IR D P R IO R IT Y291. Develop a Strategy2. Review the design /process EFFECTCAUSES301. Develop a Strategy2. Review the design /process3. List functionsDevelop a StrategyReview the design/processList functions311. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm

45、 potential failure modesBasic Steps:1. Develop a strategy2. Review the design/process3. List functions4. Brainstorm potential failure modes321. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. Organize potential failure modestopictopicAffinity D

46、iagram331. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. Organize potential failure modes6. Analyze potential failure modes341. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. Organize p

47、otential failure modes6. Analyze potential failure modes7. Establish risk priorityVITALFEWTRIVIALMANY351. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. Organize potential failure modes6. Analyze potential failure modes7. Establish risk priori

48、ty8. Take action to reduce risk361. 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 risk9. Calculate resulting RPNsO*S*D=RPN371

49、. 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 risk9. Calculate resulting RPNs10. Follow up38IFTHENHOW DOI KNOW?CAUSEFAILURE

50、 MODEEFFECT39The design or process must be improved based on the results of the FMEA study.A well-developed FMEA will be of limited value without positive and effective corrective actions.40Describe FMEA principles and techniques. Summarize the concepts, definitions, application options and relation

51、ships with other tools.Perform a FMEA41Describe FMEA principles and techniques. Summarize the concepts, definitions, application options and relationships with other tools.Perform a FMEA4243Eyelash Learning CurveABILITY TODO JOBTIMEOLD EMPLOYEE LEAVESWITH KNOWLEDGENEW EMPLOYEE BEGINS There is no org

52、anizational memory to allow people to start where their predecessors left off Nothing in place to capture the new or improved methods that produce results44ABILITY TODO JOBTIMENEW EMPLOYEE COMES ONAND PICKS UP ALMOST WHEREPREVIOUS EMPLOYEE LEFT OFF Organization continues to advance its knowledge by

53、preserving the lessons each learns Rapid learning = less waste, less complexity, higher customer value, lower costs45Two key ingredients:1. Having best known methods documented2. Training people on what those methods areWho to train?lNew employeeslManagerslExperienced employeesSix Sigma46Advantages:

54、 优点优点lCustomer progress is more visible and can be tracked over time 顾客进步更可见而且可以随时间跟踪顾客进步更可见而且可以随时间跟踪lCapture and share lessons learned吸取和分享教训吸取和分享教训lSystem itself does not become a source of variation系统自身不会成为变异的来源系统自身不会成为变异的来源l Leads to efficient practices 导致有效率的实践导致有效率的实践 47Disadvantages: 缺点缺点lSti

55、fle creativity and lead to stagnation 抑制创造力导致停滞不前抑制创造力导致停滞不前lInterfere with customer focus 干涉客户的焦点干涉客户的焦点lAdd bureaucracy and red tape 助长官僚作风助长官僚作风lMake work inflexible and boring 使工作欠缺灵活性，使人容易感到厌烦使工作欠缺灵活性，使人容易感到厌烦lOnly describe the minimal acceptable output只描述最小的可接受输出只描述最小的可接受输出48The difficulty we

56、face is . . . .the arguments for and against standardization are both true 公说公有理，婆说婆有理公说公有理，婆说婆有理To achieve a balance, develop standards judiciously - where it matters the mostWhen effectively managed, standards provide the foundation for improvement 49Companies that use standardization effectively

57、operate very differently:lThe company knows why it is developing standards and how they contribute to its overall purposelManagement uses best-known methods themselves and strongly supports and checks usagelEmployees understand how different facets of their work affect the products and services lEmp

58、loyees know which elements/functions are critical to producing high-quality output50Leverage Point: A place where a little change has a great impact 支点：小小的变化就能有巨大的影响的地方。支点：小小的变化就能有巨大的影响的地方。三两拨千斤？三两拨千斤？“ . every job, every process, has within it high-leverage points that we must standardize if we wan

59、t to achieve consistently high performance, and low-leverage points where standardization is superfluous, serving only to restrict flexibility.”51“Knowledge about what is not important is almost as valuable as knowledge about what is important. It frees our attention to better focus on the few thing

60、s that make a difference.” “This kind of flexibility shows up in all jobs.” “As a rule of thumb, keep the degree of standardization as low as possible but do not neglect any leverage points.” 52Knowing the leverage points is critical for determining priorities and strategies for improvementVital FewTrivial ManyPareto Pr