FMEA失效模式及其影响分析.ppt

1、Failure Mode and Effect Analysis失 效 模 式 及 其 影 响 分 析,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。,FMEA: Failure Modes and Effect

2、s 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能力,并提供了

3、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. Our mai

4、n 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 reduction pr

5、ojects. FMEA也是一个在失效缩小的管理任务的有价值的工具。,FMEA,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 elimina

6、te 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,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

7、事情 Wrong application 应用错误,A Failure Mode is . . .失效模式是,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 all

8、 of us focus on eliminating product and process concerns and prevent problems from recurring Reduce the product development timing and cost,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 FM

9、EA 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.,NASA used FMEA to identify Single Point Failures on Apollo project (SPF = no redundancy 1 represents 6 sigma.

10、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 on a provided scale fr

11、om 1 to 10. A 10 implies the control will not detect the presence of a failure; a 1 suggests detection is nearly certain.,Process Failure Mode,The potential failure mode is the manner in which the process could fail to perform its intended function. The failure mode for a particular operation could

12、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,Process Causes,Process FMEA considers process variability due to:,Current Controls,Assessment of the abil

13、ity 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,Testing,DOE,Types of Measures,SEVERITY As it applies to the effects on the local sys

14、tem, 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 failure mode,Typically, three items are scored:,Risk Priority Number,RPN = O x S x D Occ

15、urrence x Severity x Detection,O,S,D,x,x,= RPN,Shortcomings of RPN,A 8 4 3 96 B 4 8 3 96,SAME RESULT,Failure Mode,Severity,Occurrence,Effectiveness,RPN,Severity,Occurance,Detection,It is conducted on a timely basis and It is applied by a product team and Its results are documented,FMEA is Most Effec

16、tive When,What 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 variation,Choose designs or processes which . . .,FMEA Process,Buyer,Process Operator,Process Knowledge,Previous Experience,

17、Past Problems,Chronic Problems,Process Functions, Potential Failure Modes,Effects, Causes, Current Controls,Action Priority,Actions to Eliminate or Reduce Failure Mode,Warranty Claims,Basic Steps,1. Develop a Strategy,1. Develop a Strategy 2. Review the design /process,Basic Steps,Basic Steps,1. Dev

18、elop a Strategy 2. Review the design /process 3. List functions,1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes,Basic Steps,1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. Organ

19、ize potential failure modes,Basic Steps,topic,topic,Affinity Diagram,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,Basic Steps,1. Develop a Strategy 2. Review the desi

20、gn /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,1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. Organize po

21、tential failure modes 6. Analyze potential failure modes 7. Establish risk priority 8. Take action to reduce risk,Basic Steps,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 m

22、odes 7. Establish risk priority 8. Take action to reduce risk 9. Calculate resulting RPNs,Basic Steps,O*S*D=RPN,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. Establ

23、ish risk priority 8. Take action to reduce risk 9. Calculate resulting RPNs 10. Follow up,Basic Steps,Testing the Relationships,IF,THEN,HOW DO I KNOW?,CAUSE,FAILURE MODE,EFFECT,Actions,The design or process must be improved based on the results of the FMEA study.,A well-developed FMEA will be of lim

24、ited value without positive and effective corrective actions.,Module Objectives,Describe FMEA principles and techniques. Summarize the concepts, definitions, application options and relationships with other tools. Perform a FMEA,Describe FMEA principles and techniques. Summarize the concepts, defini

25、tions, application options and relationships with other tools. Perform a FMEA,Module Objectives.,Organizational Learning and Systems Thinking 组织学习和系统思维,A Management System,Building Organizational Memory,Eyelash Learning Curve,There is no organizational memory to allow people to start where their pre

26、decessors left off Nothing in place to capture the new or improved methods that produce results,*,Rapid Learning Curve,ABILITY TO DO JOB,TIME,NEW EMPLOYEE COMES ON AND PICKS UP ALMOST WHERE PREVIOUS EMPLOYEE LEFT OFF,Organization continues to advance its knowledge by preserving the lessons each lear

27、ns Rapid learning = less waste, less complexity, higher customer value, lower costs,*,How Do We Create Rapid Learning?,Two key ingredients: 1. Having best known methods documented 2. Training people on what those methods are Who to train? New employees Managers Experienced employees,*,Six Sigma,Pros

28、 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 learned 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,*,Pros and Cons of Standard M

29、ethods,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 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,Finding a Balance 寻找平衡,The difficulty we f

30、ace 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 the most When effectively managed, standards provide the foundation for improvement,Effective Standardization 有效的标准,Companies that use standar

31、dization effectively operate very differently: The company knows why it is developing standards and how they contribute to its overall purpose Management uses best-known methods themselves and strongly supports and checks usage Employees understand how different facets of their work affect the produ

32、cts and services Employees know which elements/functions are critical to producing high-quality output,Create Standards Judiciously 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。 三两拨千斤？ “ . every job, every process, has within it high-leverage points th

33、at we must standardize if we want to achieve consistently high performance, and low-leverage points where standardization is superfluous, serving only to restrict flexibility.”,Know What Is and What Is Not Important,“Knowledge about what is not important is almost as valuable as knowledge about what

34、 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.”,Leverage Point Thinking - How Do You T

35、urn the Ship?,Knowing the leverage points is critical for determining priorities and strategies for improvement,Vital Few,Trivial Many,Pareto Principle 80% of the problems are caused by only about 20% of the contributing factors,*,Whats the Connection? 联系,Companies run into trouble because they chan

36、ge 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 their processes without controlling the factors that made them essential.,Resist the temptation to change until we determine: Are the documented stan

37、dards the best? What is the impact on the rest of the system? Are the methods actually being followed?,Whats the Connection?,Employee Responsibility 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

38、 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 with immediate feedback on performance. Dont be vague or require interpretation (i.e. words like flat, smooth, etc.),Employee Responsibility (cont),3. Have

39、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 all 3 - in order! (See Appendix A for Checklist),CAP-Do - Determine the Need for Standardization,1. Check Make sure we know why the work is being done See i

40、f the purpose is clearly documented Compare actual practice with documented methods If no documented methods exist, compare different practices among people doing the work Compare how the effectiveness of the work is supposed to be checked and how it is actually checked,To answer these questions, use the