FMEA讲议.ppt

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1、Failure Mode and Effect Analysis失失 效效 模模 式式 及及 其其 影影 响响 分分 析析1Module Objectives课程目的课程目的Describe 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

2、一个执行一个FMEA。2FMEA:Failure Modes and Effects AnalysisFMEA is a systematic approach used 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

3、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 generally 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 t

4、o know failure modes.Our main interests are the cause and likelihood of 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 de

5、fect/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。FMEA3Definition of FMEA 定义定义1.recognize 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.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.ident

6、ify actions which could eliminate or reduce the chance of the potential failure occurring,确定确定消除或减少潜在失效发生机会的行动3.document the process.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 occurrin

7、g 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A Failure Mode is.失效模式是失效模式是5FMEA Use by Black/Brown/Green BeltslTo identify potential failure modes and rate the severity of their effectslTo identify critical characteristics and significant characteristicslTo rank potential design a

8、nd process deficiencieslTo help all of us focus on eliminating product and process concerns and prevent problems from recurringlReduce the product development timing and cost6BackgroundDeveloped in early 60s by NASA to“fail-proof”Apollo missions.Adopted in early 70s by US Navy.By late 80s,automotive

9、 industry had implemented FMEA and began requiring suppliers do the same.Liability costs were the main driving force.Used sporadically throughout industry during 1980s.Adopted by MSI in?Six Sigma is the catalyst.7NASA used FMEA to identify Single Point Failures on Apollo project(SPF=no redundancy&lo

10、ss of mission).How many did they find?420and we thought we had problems!8Types of FMEAsSYSTEM DESIGNPROCESSSystem FMEA is used to analyze systems and subsystems in the early concept and design stages.Design FMEA is used to analyze products before they are released to productionProcess FMEA is used t

11、o analyze manufacturing,assembly and administrative processes9When is the FMEA Started?“Do the best you can with what you have”AS EARLY AS POSSIBLE!Guideline:10When to Start?When new systems,products and processes are being designedWhen existing designs and processes are being changedWhen carry-over

12、 designs or processes will be used in new applications or environmentsAfter completing a Problem Solving Study,to prevent recurrence of a problem11Beginning and End12Effect of FMEA on Process and Design changesDesign StartDevelopmentProduction ReleaseProduction TimeNo of Engineering ChangesTradition

13、al approachFMEA approach13Process FMEA Form1415Elements of FMEAFailure 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 downstream operation and the end user.Severity Us

14、ing 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 likelihood of the failure occurring.10 represents near cert

15、ainty;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 The effectiveness of each current control method is rated

16、 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.16Process Failure ModelThe potential failure mode is the manner in which the process could fail to perform its intended function.lThe failure mode for a parti

17、cular operation could be a cause in a subsequent(downstream)operation or an effect associated with a potential failure in a previous(upstream)operation.FAILUREMODEEFFECTPREVIOUSOPERATIONCAUSENEXTOPERATION17Process Causes Process FMEA considers process variability due to:OPERATORSET-UPMACHINEMETHODEN

18、VIRONMENTMEASUREMENT18Current ControlsuAssessment 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&RSamplingTestingDOE19Types of Measure

19、sSEVERITYAs 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 scor

20、ed:20Risk Priority NumberRPN=O x S x D Occurrence x Severity x DetectionOSD xx=RPN21Shortcomings of RPNA 8 4 3 96B 4 8 3 96SAME RESULTFailure ModeSeverityOccurrenceEffectivenessRPN22Severity23Occurance24Detection25It is conducted on a timely basisandIt is applied by a product teamandIts results are

21、documentedFMEA is Most Effective When 26What Is A Good Application?Involve new technology Have changed from previous Are chronically 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

22、chronically in troubleHave a high degree of operator controlHave a high degree of variationChoose designs or processes which.27FMEA ProcessManufacturing EngineerBuyerProcessOperatorProcess KnowledgePrevious ExperiencePast ProblemsChronic ProblemsReliabilityEngineerProcess Functions,Potential Failure

23、 ModesEffects,Causes,Current ControlsAction PriorityActions to Eliminate or Reduce Failure ModeWarranty Claims28Basic Steps1.Develop a Strategy291.Develop a Strategy2.Review the design/process EFFECTCAUSESBasic Steps30Basic Steps1.Develop a Strategy2.Review the design/process3.List functionsDevelop

24、a StrategyReview the design/processList functions311.Develop a Strategy2.Review the design/process3.List functions4.Brainstorm potential failure modesBasic StepsBasic Steps:1.Develop a strategy2.Review the design/process3.List functions4.Brainstorm potential failure modes321.Develop a Strategy2.Revi

25、ew the design/process3.List functions4.Brainstorm potential failure modes5.Organize potential failure modesBasic StepstopictopicAffinity Diagram331.Develop a Strategy2.Review the design/process3.List functions4.Brainstorm potential failure modes5.Organize potential failure modes6.Analyze potential f

26、ailure modesBasic Steps341.Develop a Strategy2.Review the design/process3.List functions4.Brainstorm potential failure modes5.Organize potential failure modes6.Analyze potential failure modes7.Establish risk priorityVITALFEWTRIVIALMANYBasic Steps351.Develop a Strategy2.Review the design/process3.Lis

27、t functions4.Brainstorm potential failure modes5.Organize potential failure modes6.Analyze potential failure modes7.Establish risk priority8.Take action to reduce riskBasic Steps361.Develop a Strategy2.Review the design/process3.List functions4.Brainstorm potential failure modes5.Organize potential

28、failure modes6.Analyze potential failure modes7.Establish risk priority8.Take action to reduce risk9.Calculate resulting RPNsBasic StepsO*S*D=RPN371.Develop a Strategy2.Review the design/process3.List functions4.Brainstorm potential failure modes5.Organize potential failure modes6.Analyze potential

29、failure modes7.Establish risk priority8.Take action to reduce risk9.Calculate resulting RPNs10.Follow upBasic Steps38Testing the RelationshipsIFTHENHOW DOI KNOW?CAUSEFAILURE MODEEFFECT39ActionsThe design or process must be improved based on the results of the FMEA study.A well-developed FMEA will be

30、 of limited value without positive and effective corrective actions.40Describe FMEA principles and techniques.Summarize the concepts,definitions,application options and relationships with other tools.Perform a FMEAModule Objectives.42Organizational Learning and Systems Thinking 组织学习和系统思维组织学习和系统思维A M

31、anagement SystemA Management System43Building Organizational MemoryEyelash Learning CurveABILITY TODO JOBTIMEOLD EMPLOYEE LEAVESWITH KNOWLEDGENEW EMPLOYEE BEGINSThere is no organizational memory to allow people to start where their predecessors left offNothing in place to capture the new or improved

32、 methods that produce results*44Rapid Learning CurveABILITY TODO JOBTIMENEW EMPLOYEE COMES ONAND PICKS UP ALMOST WHEREPREVIOUS EMPLOYEE LEFT OFFOrganization continues to advance its knowledge by preserving the lessons each learnsRapid learning=less waste,less complexity,higher customer value,lower c

33、osts*45How Do We Create Rapid Learning?Two key ingredients:1.Having best known methods documented2.Training people on what those methods areWho to train?lNew employeeslManagerslExperienced employees*Six Sigma46Pros and Cons of Standard Methods Advantages:优点优点lCustomer progress is more visible and ca

34、n 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 *47Pros and Cons of Standard MethodsDisadvantages:缺点缺点lStifle creativit

35、y 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48Finding a Balance 寻找平衡寻找平衡The d

36、ifficulty we 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 49Effective Standardization 有效的标准Companies that

37、 use standardization effectively 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 affe

38、ct the products and services lEmployees know which elements/functions are critical to producing high-quality output50Create Standards Judiciously 明智地创造标准明智地创造标准Leverage 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 proces

39、s,has within it high-leverage points that we must standardize if we want to achieve consistently high performance,and low-leverage points where standardization is superfluous,serving only to restrict flexibility.”51Know What Is and What Is Not Important“Knowledge about what is not important is almos

40、t as valuable as knowledge about what is important.It frees our attention to better focus on the few things 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.”52Leve

41、rage Point ThinkingLeverage Point Thinking-How Do You Turn the Ship?How Do You Turn the Ship?Knowing the leverage points is critical for determining priorities and strategies for improvementVital FewTrivial ManyPareto Principle 80%of the problems are caused by only about 20%of the contributing facto

42、rs*5354Whats the Connection?联系联系Companies run into trouble because they change their methods before they understand why the methods are there in the first place.陷入麻烦的公司陷入麻烦的公司是因为他们在不了解现有方法存在的原因之前就盲目改变是因为他们在不了解现有方法存在的原因之前就盲目改变它。它。They eliminate safety nets in their processes without controlling the f

43、actors that made them essential.55Resist the temptation to change until we determine:Are the documented standards the best?What is the impact on the rest of the system?Are the methods actually being followed?Whats the Connection?56Employee Responsibility 员工的责任员工的责任Before anyone can be held responsib

44、le for the quality of their own work,they must:1.Know the job 了解工作了解工作lIs the job clearly documented?lAre goals and targets visible?lHas adequate training been done?lDo workers know how product is used?2.Know the standard 了解标准了解标准lOutput must be measurable with immediate feedback on performance.lDon

45、t be vague or require interpretation (i.e.words like flat,smooth,etc.)57Employee Responsibility(cont)3.Have the ability to regulate 拥有调节的能力拥有调节的能力lWhen the job does not meet the standard,are there reaction procedures?lAre best practices leveraged?Must have all 3-in order!(See Appendix A for Checklis

46、t)58CAP-Do-Determine the Need for StandardizationCAP-Do-Determine the Need for Standardization1.CheckMake sure we know why the work is being done See if the purpose is clearly documentedCompare actual practice with documented methodsIf no documented methods exist,compare different practices among pe

47、ople doing the workCompare how the effectiveness of the work is supposed to be checked and how it is actually checkedPLANDOACTCHECKTo answer these questions,use the CAP-Do(variation of Demings PDCA-Plan-Do-Check-Act)59CAP-Do-Determine the Need for StandardizationCAP-Do-Determine the Need for Standar

48、dization 2.ActReconcile actual practices and documentationChange one to match the other as appropriateIf no standard methods are in place and no one can demonstrate(with data)that consistency among operators exists,simply agree on a method that all will use.This will establish a consistent baseline

49、upon which improvements can be built.PLANDOACTCHECK603.PlanDetermine how to detect flaws and potential improvements in the standardConduct a Potential Problem Analysis(Kepner-Tregoe)to determine contingencies and triggers for contingenciesDevelop a plan for upgrading the documentation,or for making

50、it more usefulDevelop a plan for encouraging the use of the documented standardCAP-Do-Determine the Need for StandardizationCAP-Do-Determine the Need for Standardization PLANDOACTCHECK614.DoTrain to the new documented standardUse the new standard5.CheckOnce again compare actual practices to document