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1、FMEA Outline,Section 1: What is FMEA Section 2: FMEA Purpose Section 3: Elementary Concepts of FMEA Section 4: Development of FMEA Section 5: Process FMEA Application Example,Process PFMEA Analysis Sheet,Section 1:What Is FMEA,What is FMEA,FMEA is the prefix of Potential Failure Mode and Effects Ana
2、lysis. The word potential is omitted. FMEA is a systematic method which identifies potential product problems in the following areas. Product design. Product manufacture. Product use. FMEA is developed by Chrysler,Ford,General Motors . FMEA including DFMEA-Design FMEA & PFMEA-Process FMEA. Based on
3、SAE product characteristic, we will study PFMEA detailedly.,FMEA History,Mid -60s: Started in the Aerospace Industries. 1974: Navy created FMEA Standard. 1976: US Department of Defense adopted an FMEA standard. Late 70s: Automotive Industries started to use FMEA. Early 80s: Micro Electronic Industry
4、 started to apply FMEA to assist in improving the “yield of memory devices”. Mid 80s: Automotive industries started to apply FMEA to the manufacturing processes. 90s: TQS 9000 recommended adoption of FMEA.,Section 2:FMEA Purpose,FMEA Purpose,Control tool. Design control. Manufacturing control. Risk
5、analysis tool. Management tool. Prioritize product improvement activity. Continuous improvement tool. What do we do next?,To reduce product or service concerns and to minimize the probability of defective product reaching the customer. To identify potential failure modes and to rate the severity of
6、their effects. To identify the critical characteristics of the product or process. To rank the order of potential design and process defects.,FMEA Purpose,FMEA application in SAE,Nonconforming prevention and correction Failure analysis QCC tools, major cause confirmation, action taking,and effect co
7、mparison Others engineering area,Section 3:Elementary Concepts of FMEA,FMEA Concepts,Function, what is supposed to happen here. What is the product or process objective. Failure Mode, what can go wrong here. Two Types of failure modes. Failure to perform the required function. Performs function poor
8、ly. Performs a function that is not supposed to be there. Cause, how can it go wrong. Four types of possible causes. Design related. Manufacturing process related. Application related. Service related.,FMEA Concepts,Effect, what happens when it goes wrong: Design possible effects. Product end user.
9、Local user. Other, in between users. Process possible effects. The product effects. Process effects. Detection, can it be detected if it goes wrong. P-Type controls- Preventing it from happening. D- Type controls - Detect it if goes wrong.,Potential Cause of Failure,List all possible conceivable cau
10、ses of each failure mode. The list should be complete as possible so that corrective actions can be implemented effectively and timely. It must be a process or manufacturing cause. Use as much detail as possible to define the cause of the failure. Consider: Method, machinery, materials, people and e
11、nvironment.,Effects,An effect of the failure mode that would be noticed or experienced at the next operation, at a subsequent operation, by any downstream user. Consider: Next user. Ultimate user or customer. Product operation. Government regulations.,Severity Definition,Severity is the assessment o
12、f the failure effects on the process as well as the product. Severity rating apply to the effects and the effects only. Severity assessment is focusing on both the process / operation and the product. All causes of a failure mode having the same effect should be assigned the same severity ranking. S
13、everity ranking scale goes from 1 to 10.,Failure Mode Severity (S),Severity is a rating corresponding to the seriousness of the effect of the potential failure mode. SeverityDescription (1) No effect on the system performance. (2) Very slight Effect. Nuisance fault noticed. (3) Slight Effect. Nuisan
14、ce fault obvious. (4) Minor Effect. Chronic nuisance fault. (5) Moderate Effect. Nuisance repair required. (6) Significant Effect. Repair required. (7) Major Effect. Rework /repairs required. (8) Serious Effect. Equipment/very dissatisfied customer. (9) Very Serious Effect. Stop ship required. (10)H
15、azardous Effect, sudden failure , or non-compliance to regulations or liability issue.,Current Controls,Current controls are intended to prevent the cause of the failure from occurring, to detect the cause if it should occur, and to reduce the impacts of the failure effects. For example: SPC. Fixtur
16、e fool proofing. Process DOE. SE. approval. Production validation. Preventive maintenance program. Gauge R-R study. Operator training.,Occurrence Definition,The occurrence rating corresponding to the rate at which the cause and the resulting failure mode will occur over the life of the product and before any additional process controls are developed. A cause of the failure mode is a deficiency that results in a failure mode. It is a description of how the process could cause a failure to occur.
