1、1,Failure Mode and Effect Analysis 失 效 模 式 及 其 影 响 分 析,2,Module Objectives课程目的,Describe FMEA principles and techniques. 描述FMEA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。 Perform a FMEA 执行一个FMEA。,3,FMEA: Failure Modes and
2、 Effects Analysis FMEA 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
3、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 to know failure modes. O
4、ur 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 defect/failure reducti
5、on projects. FMEA也是一个在失效缩小的管理任务的有价值的工具。,FMEA,4,Definition of FMEA 定义,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 identify actions which could e
6、liminate or reduce the chance of the potential failure occurring,确定消除或减少潜在失效发生机会的行动 document the process.使过程形成文件,FMEA is a systematic design evaluation procedure whose purpose is to: 是系统的设计评估程序,5,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
7、想要的事情Wrong application应用错误,A Failure Mode is . . .失效模式是,6,FMEA Use by Black / Brown / Green Belts,To identify potential failure modes and rate the severity of their effects To identify critical characteristics and significant characteristics To rank potential design and process deficiencies To help
8、all of us focus on eliminating product and process concerns and prevent problems from recurring Reduce the product development timing and cost,7,Background,Developed in early 60s by NASA to “fail-proof” Apollo missions.Adopted in early 70s by US Navy .By late 80s, automotive industry had implemented
9、 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.,8,NASA used FMEA to identify Single Point Failures on Apollo project (SPF = no redundancy & loss of mission).
10、How many did they find? 420 and we thought we had problems!,9,Types of FMEAs,SYSTEM,DESIGN,PROCESS,System 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 production,Process FMEA is used to anal
11、yze manufacturing, assembly and administrative processes,10,When is the FMEA Started?,“Do the best you can withwhat you have”,AS EARLY AS POSSIBLE!,Guideline:,11,When to Start ?,When new systems, products and processes are being designed When existing designs and processes are being changed When car
12、ry-over designs or processes will be used in new applications or environments After completing a Problem Solving Study, to prevent recurrence of a problem,12,Beginning and End,13,Effect of FMEA on Process and Design changes,Design Start,Development,Production Release,Production,Time,No of Engineerin
13、g Changes,Traditional approach,FMEA approach,14,Process FMEA Form,15,JL Example,16,Elements of FMEA,Failure 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
14、 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 likelihood of t
15、he 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 The effe
16、ctiveness 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.,17,Process Failure Mode,The potential failure mode is the manner in which the process could fail to perfor
17、m its intended function. The 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.,FAILURE MODE,EFFECT,PREVIOUS OPERATION,CAUSE,NEXT OPERATION,18,Process Causes,Process FMEA
18、 considers process variability due to:,19,Current Controls,Assessment of the ability of the control to detect the failure before the item leaves the manufacturing area and ships to the customer. Capability of all controls in the process to prevent escapes,SPC,Process Capability,Gage R&R,Sampling,Tes
19、ting,DOE,20,Types of Measures,SEVERITY As it applies to the effects on the local system, next level, and end user OCCURRENCE Likelihood that a specific cause will occur and result in a specific failure mode DETECTION Ability of the current / proposed control mechanism to detect and identify the fail
20、ure mode,Typically, three items are scored:,21,Risk Priority Number,RPN = O x S x DOccurrence xSeverity xDetection,O,S,D,x,x,= RPN,22,Shortcomings of RPN,A 8 4 3 96B 4 8 3 96,SAME RESULT,Failure Mode,Severity,Occurrence,Effectiveness,RPN,23,Severity,24,Occurance,25,Detection,26,It is conducted on a
21、timely basisandIt is applied by a product teamandIts results are documented,FMEA is Most Effective When,27,What Is A Good Application?,Involve new technologyHave changed from previousAre chronically in troubleHave a high degree of operator controlHave a high degree of variation,Choose designs or pro
22、cesses which . . .,28,FMEA Process,Buyer,Process Operator,Process Knowledge,Previous Experience,Past Problems,Chronic Problems,Process Functions, Potential Failure Modes,Effects, Causes, Current Controls,Action Priority,Actions to Eliminate or Reduce Failure Mode,Warranty Claims,29,Basic Steps,1. De
23、velop a Strategy,30,1. Develop a Strategy 2. Review the design /process,Basic Steps,31,Basic Steps,1. Develop a Strategy 2. Review the design /process 3. List functions,32,1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failuremodes,Basic Steps,33,1. Dev
24、elop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. Organize potential failuremodes,Basic Steps,topic,topic,Affinity Diagram,34,1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. Organize
25、 potential failure modes 6. Analyze potential failure modes,Basic Steps,35,1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. Organize potential failure modes 6. Analyze potential failure modes 7. Establish risk priority,Basic Steps,36,1. D
26、evelop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. Organize potential failure modes 6. Analyze potential failure modes 7. Establish risk priority 8. Take action to reduce risk,Basic Steps,37,1. Develop a Strategy 2. Review the design /process 3
27、. List functions 4. Brainstorm potential failure modes 5. Organize potential failure modes 6. Analyze potential failure modes 7. Establish risk priority 8. Take action to reduce risk 9. Calculate resulting RPNs,Basic Steps,O*S*D=RPN,38,1. Develop a Strategy 2. Review the design /process 3. List func
28、tions 4. Brainstorm potential failure modes 5. Organize potential failure modes 6. Analyze potential failure modes 7. Establish risk priority 8. Take action to reduce risk 9. Calculate resulting RPNs 10. Follow up,Basic Steps,39,Testing the Relationships,IF,THEN,HOW DO I KNOW?,CAUSE,FAILURE MODE,EFF
29、ECT,40,Actions,The 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.,41,Module Objectives,Describe FMEA principles and techniques. Summarize the concepts, definitions, applicati
30、on options and relationships with other tools.Perform a FMEA,42,Describe FMEA principles and techniques. Summarize the concepts, definitions, application options and relationships with other tools.Perform a FMEA,Module Objectives.,43,Organizational Learning and Systems Thinking 组织学习和系统思维,A Managemen
31、t System,44,Building Organizational Memory,Eyelash Learning Curve,There is no organizational memory to allow people to start where their predecessors left off Nothing in place to capture the new or improved methods that produce results,*,45,Rapid Learning Curve,ABILITY TO DO JOB,TIME,NEW EMPLOYEE CO
32、MES ON AND PICKS UP ALMOST WHERE PREVIOUS EMPLOYEE LEFT OFF,Organization continues to advance its knowledge by preserving the lessons each learns Rapid learning = less waste, less complexity, higher customer value, lower costs,*,46,How Do We Create Rapid Learning?,Two key ingredients:1. Having best
33、known methods documented 2. Training people on what those methods areWho to train?New employees Managers Experienced employees,*,Six Sigma,47,Pros and Cons of Standard Methods,Advantages: 优点Customer 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Capture and share lessons learn
34、ed吸取和分享教训System itself does not become a source of variation系统自身不会成为变异的来源Leads to efficient practices 导致有效率的实践,*,48,Pros and Cons of Standard Methods,Disadvantages: 缺点Stifle creativity and lead to stagnation 抑制创造力导致停滞不前Interfere with customer focus 干涉客户的焦点Add bureaucracy and red tape 助长官僚作风Make work
35、 inflexible and boring 使工作欠缺灵活性，使人容易感到厌烦Only describe the minimal acceptable output只描述最小的可接受输出,49,Finding a Balance 寻找平衡,The difficulty we face is . . . . the arguments for and against standardization are both true 公说公有理，婆说婆有理 To achieve a balance, develop standards judiciously - where it matters th
36、e most When effectively managed, standards provide the foundation for improvement,50,Effective Standardization 有效的标准,Companies that use standardization effectively operate very differently:The company knows why it is developing standards and how they contribute to its overall purposeManagement uses
37、best-known methods themselves and strongly supports and checks usageEmployees understand how different facets of their work affect the products and servicesEmployees know which elements/functions are critical to producing high-quality output,51,Create Standards Judiciously 明智地创造标准,Leverage Point: A
38、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。 三两拨千斤？“ every job, every process, 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 restric
39、t flexibility.”,52,Know What Is and What Is Not Important,“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 things that make a difference.” “This kind of flexibility shows up in all jobs.”“As a rule of
40、 thumb, keep the degree of standardization as low as possible but do not neglect any leverage points.”,53,Leverage Point Thinking - How Do You Turn the Ship?,Knowing the leverage points is critical for determining priorities and strategies for improvement,Vital Few,Trivial Many,Pareto Principle 80%
41、of the problems are caused by only about 20% of the contributing factors,*,54,55,Whats the Connection? 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。They eliminate safety nets in
42、their processes without controlling the factors that made them essential.,56,Resist 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?,57,Employee Responsibil
43、ity 员工的责任,Before anyone can be held responsible for the quality of their own work, they must:1. Know the job 了解工作 Is the job clearly documented? Are goals and targets visible? Has adequate training been done? Do workers know how product is used?2. Know the standard 了解标准 Output must be measurable wit
44、h immediate feedback on performance. Dont be vague or require interpretation(i.e. words like flat, smooth, etc.),58,Employee Responsibility (cont),3. Have the ability to regulate 拥有调节的能力 When the job does not meet the standard, are there reaction procedures? Are best practices leveraged?Must have al
45、l 3 - in order! (See Appendix A for Checklist),59,CAP-Do - Determine the Need for Standardization,1. Check Make sure we know why the work is being doneSee if the purpose is clearly documentedCompare actual practice with documented methodsIf no documented methods exist, compare different practices am
46、ong people doing the workCompare how the effectiveness of the work is supposed to be checked and how it is actually checked,To answer these questions, use the CAP-Do (variation of Demings PDCA - Plan - Do - Check - Act),60,CAP-Do - Determine the Need for Standardization,2. Act Reconcile actual pract
47、ices anddocumentationChange one to match the other asappropriateIf 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 upon which improvements can be bui
48、lt.,61,3. Plan Determine how to detect flawsand potential improvements inthe standardConduct a Potential ProblemAnalysis (Kepner-Tregoe) to determinecontingencies and triggers for contingenciesDevelop a plan for upgrading thedocumentation, or for making it more usefulDevelop a plan for encouraging t
49、he use of the documented standard,CAP-Do - Determine the Need for Standardization,62,4. Do Train to the new documentedstandard Use the new standard5. Check Once again compare actual practicesto documented standards Investigate inconsistencies6. Act Reconcile the actual practice with the documentation Make changes based on the data!,CAP-Do - Determine the Need for Standardization,63,“The Illiterate of the Year 2000 . . . 2000年的文盲,. . . will not be the individual who cannot read and write, but the one who cannot learn, unlearn and relearn” 不是不会读和写的人，而是不能学习、再学习和重新学习的人Alvin Toffler,
