PFMEA 风险降低.

1、 General Motors Corporation. All rights reserved.QSB WORKSHOP REV. 112404 1风险降低程序风险降低程序提前行动提前行动RPN 降低程序降低程序:降低潜在的质量失效风险降低潜在的质量失效风险反应行动反应行动针对质量失效的防错措施针对质量失效的防错措施 General Motors Corporation. All rights reserved.QSB WORKSHOP REV. 112404 2程序失效模式程序失效模式 & 结果分析结果分析(PFMEA)定义定义是一种针对各程序步骤的分析技术，能识别出: 程序无法达

2、到要求的形式 对内、外部顾客导致的影响 (severity严重度). 失效情况发生的频次 (occurrence发生频度). 当前控制的效果 (prevention & detection预防&探测). 原因和结果等级 (risk priority number风险顺序号).是一个结构性程序，用于识别、优先排序和删除同失效模式相关的程序 General Motors Corporation. All rights reserved.QSB WORKSHOP REV. 112404 3REVD DATE :MODEL YEAR / CARLINE :FMEA DATE :PROD

3、UCTION PLANT :FMEA CONDUCTED BY :10 Correct Part - pilot bearingIncorrect part installedMisbuild7Manual: incorrectly selected7No preventionNo detection10 49020Correct sub-assyIncorrect or reversed sub-assemblyunable to install 7Machine Vision ID Incorrect3No preventionIn-line Audits6 126PROCESS NAME

4、/ NUMBERPROCESS FUNCTIONPOTENTIAL FAILURE MODEPOTENTIAL EFFECT(S) OF FAILURESEVCLASSPOTENTIAL CAUSE(S)/ MECHANISM(S) OF FAILUREOCCDETRPNPREVENTIONDETECTIONCURRENT CONTROLSB/P Level: 001, 7-NOV-02Sensor to detect bearing typeShad, B.3/1/0277 4 112New Laser Station.NA 73 242RECOMMENDED ACTION(S)RESPON

5、SIBILITY & TARGET COMPLETION DATEACTION RESULTSACTIONS TAKENSEVOCCDETRPNWhat can go wrong?How does it affect customer?How often does this cause happen?How likely are we to notice if this happens?How high is the risk? PROCESS FAILURE MODE & EFFECTS ANALYSIS(AIAG PFMEA Third Edition)(Example)

6、General Motors Corporation. All rights reserved.QSB WORKSHOP REV. 112404 4 Effect Criteria: Severity of Effect This ranking results when a potential failure mode results in a final customer and/or a manufacturing/assembly plant defect. The final customer should always be considered first. If both oc

7、cur, use the higher of the two severities. (Customer Effect) Criteria: Severity of Effect This ranking results when a potential failure mode results in a final customer and/or a manufacturing/assembly plant defect. The final customer should always be considered first. If both occur, use the higher o

8、f the two severities. (Manufacturing/Assembly Effect) Ranking Hazardous without warning Very high severity ranking when a potential failure mode affects safe vehicle operation and/or involves noncompliance with government regulation without warning. Or may endanger operator (machine or assembly) wit

9、hout warning. 10 Hazardous with warning Very high severity ranking when a potential failure mode affects safe vehicle operation and/or involves noncompliance with government regulation with warning. Or may endanger operator (machine or assembly) with warning. 9 Very High Vehicle/item inoperable (los

10、s of primary function). Or 100% of product may have to be scrapped, or vehicle/item repaired in repair department with a repair time greater than one hour. 8 High Vehicle/item operable but at a reduced level of performance. Customer very dissatisfied. Or product may have to be sorted and a portion (

11、less than 100%) scrapped, or vehicle/item repaired in repair department with a repair time between a half-hour and an hour. 7 Moderate Vehicle/item operable but Comfort/Convenience item(s) inoperable. Customer Dissatisfied. Or a portion (less than 100%) of the product may have to be scrapped with no

12、 sorting, or a vehicle/item repaired in repair department with a repair time less than a half-hour. 6 Low Vehicle/Item operable but Comfort/Convenience item(s) operable but at a reduced level of performance. Or 100% of product may have to be reworked, or vehicle/item repaired off-line but does not g

13、o to repair department. 5 Very Low Fit and Finish/Squeak and Rattle item does not conform. Defect noticed by most customers (greater than 75%). Or the product may have to be sorted, with no scrap, and a portion (less than 100%) reworked. 4 Minor Fit and Finish/Squeak and Rattle item does not conform

14、. Defect noticed by 50% of customers. Or a portion (less than 100%) of the product may have to be reworked, with no scrap, on-line but out-of-station. 3 Very Minor Fit and Finish/Squeak and Rattle item does not conform. Defect noticed by discriminating customers (less than 25%. Or a portion (less th

15、an 100%) of the product may have to be reworked with no scrap, on-line but in-station. 2 None No discernible effect. Or slight inconvenience to operation or operator, or no effect. 1 SEVERITY RANKINGS(AIAG PFMEA Third Edition) General Motors Corporation. All rights reserved.QSB WORKSHOP REV. 112404

16、5PpKRanking 0.559 0.788 0.867 0.946 1.005 1.104 1.203 1.302 1.671ProbabilityLikely Failure Rates 100 per Thousand Pieces50 per Thousand Pieces20 per Thousand Pieces10 per Thousand PiecesVery High: Persistent FailuresHigh: Frequent Failures5 per Thousand Pieces2 per Thousand Pieces1 per Thousand Piec

17、esModerate: Occasional Failures0.5 per Thousand Pieces0.1 per Thousand PiecesRemote: Failure is Unlikely 121Highest RPN valueNumber of PartsQ1 2004Q2 2004Q3 2004Q4 2004Q1 2005Q2 2005(Example: Long Term Risk Reduction Tracking Chart)Note this chart shows that the number of parts with highest RPN valu

18、es over 121 is decreasing over time, and the number of parts with a highest RPN under 40 is decreasing over time, showing significant evidence of reduced risk. General Motors Corporation. All rights reserved.QSB WORKSHOP REV. 112404 14风险降低反应风险降低反应:针对质量失效的防错措施针对质量失效的防错措施 跨部门团队应建立一份过去内、外部质量失效清单 对于每个RPN，团队正确定义PFMEA发生频度和探测度等级 团队应建立行动计划来预防失效模式 建议措施是对预防或减少失效模式的改进 当防错不可行时，应建立一个改进探测度的计划 指派