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1、Failure Mode & Effect Analysis,Explanation and Use of FMEA,What is FMEA?,FMEA is a problem solving process adopted by Snap-on as a key component of the Quality Forward System. Generally, FMEA is done by an on-site multifunctional team facilitated locally or by an SEQ Group Advanced Quality Engineer.
2、 Objective is to identify all of the reasons why quality of a process or product does not meet expectations. Uses severity, occurrence and detection ratings to determine corrective action priority for each possible failure reason.,When should a FMEA study be conducted?,As part of a Design/Developmen
3、t phase. When corrective action is needed due to unfavorable performance data (performance based on QFS metrics does not meet goals). When a need to make incremental improvement is identified by facility management or the SEQ Group.,FMEA Team Start-Up,Team Selection done by local quality coordinator
4、, business unit manager or, on request, SEQ Group Advanced Quality Engineer. Problem Statement A concise and focused description of the quality problem or opportunity for improvement, “what went wrong” or “what needs fixing”. Goal Statement a description of what is to be accomplished by the team, in
5、 quantifiable terms “reduce by”, “increase by”, “eliminate”, etc. Good metrics to use include scrap cost, rework cost, or Defects Per Million Opportunities (DPMO), etc. For example, a goal statement could be “To reduce DPMO on product family X from 3000 to 2000 by year end”. Complete FMEA Team Start
6、-Up Worksheet (example located in procedure SEQ 80.10, Figure 1).,Problem Statement & Goal Statement,Problem Statement and Goal Statement should consider: What went wrong? What is the gap between the desired quality level and the actual quality level? Which process or processes are involved? Which d
7、epartment or cell is the deficiency occurring in? Is the problem cyclic, can it be attributed to specific events? What are the appropriate metrics to measure? What is the impact on operational fitness and profitability? What is the impact on the bottom line (reduced, increased, eliminated)? Are ther
8、e constraints recognized early in the process? If so, have they been explored and clarified with the appropriate management level,FMEA Process,FMEAs uncover process problems related to the manufacture of product. Examples: a piece of automated assembly equipment may misfeed parts resulting in produc
9、ts not being assembled correctly, or, in a chemical manufacturing process, temperature or mixing time could be sources of potential failures resulting in unusable product. Think in terms of the five elements of a process: people, materials, equipment, methods and environment. With these five element
10、s in mind, ask “How can process failure affect the product, processing efficiency or safety?” Nine steps in FMEA process.,Step #1 - Review the Process,Ensure that everyone on the FMEA team has the same understanding of the process being worked on. Review blueprint/engineering drawing of product (if
11、conducting FMEA on product) and/or a detailed flowchart of the process. If these are not available, the team will need to create one. Using the blueprint and/or flowchart, team members should familiarize themselves with the product or process. They should physically see the product or a prototype of
12、 the product, and physically walk through the process exactly as the process flows. It is helpful to have an “expert” on the product or process available to answer any questions the team might have.,Step #2 Brainstorm Potential Failure Modes,Method of generating and documenting ideas of potential fa
13、ilure modes. If product or process is complex, a series of brainstorming sessions, each focused on a different element (i.e. people, methods, equipment, materials, environment), may be needed to generate a more thorough list of potential failure modes. Facilitator should write down all ideas generat
14、ed in brainstorming sessions. Once brainstorming is complete, ideas should be grouped into like categories (as determined by the team). Groups can be type of failure, where on the product failure occurred, estimated seriousness of the failure, etc. Failure modes may also be combined if they are the
15、same or very similar. Once failure modes have been grouped/combined, they should be transferred to the Potential Failure Mode and Effect Analysis Sheet (example in SEQ 80.10, Figure 2).,Step #2 (continued) Brainstorming Guidelines,Do not make any judgment on ideas. Team members should not comment on
16、 whether an idea is good or bad. Thinking should be unconventional, imaginative, or even outrageous. Aim for a large number of ideas in the shortest possible time. Team members should “hitchhike” on other ideas, by expanding them, modifying them, or producing new ones by association. All team member
17、s should participate in brainstorming process.,Step #3 List Potential Effects of Each Failure Mode,After the failure modes are listed on the FMEA worksheet form, the FMEA team needs to review each failure mode and identify the potential effects of the failure should it occur. For some failure modes,
18、 there may be only one effect, while other failure modes may have several effects. This step must be thorough this information will determine assignment of risk ratings for each of the failures. It is helpful to think of this step as an if-then process: If the failure occurs, then what are the consequences.,
