【正文】 k e y i n pu t t o gow r o n gHow often does cause occurW h a t a r et h e e x i s t i n gc o n t r o l s pr o c e d u r e s( i n s pe c t i o n t e s t ) t h a tpr e v e n t w i t ht h e c a u s e o rF a i l u r eM o d eHow well can you detect cause ot FMW h a t a r et h e a c t i o n sf o rr e d u c i n gt h eo c c u r r e n c eo f t h eCa u s e , o ri m pr o v i n gD e t e c t i o n ?S h o u l d h a v ea c t i o n s o n l yo n h i ghR P N 39。 s o re a s y f i x e s .14 C Po t e n t i a l OPro c e s s Po t e n t i a l Po t e n t i a l S l C a u s e (s ) cF a i l u re Ef f e c t (s ) o f e a M e c h a n i s m (s ) cF u n c t i o n M o d e F a i l u re v s o f F a i l u re us rPo o r t ra i n i n g 3F a i l t o d e t e c t i n t h e p ro c e s s o fi n c o m i n g i n s p e c t i o n2M i s u n d e rs t a n d i n g o f d e f e c td e f i n i t i o n2O P 1 0 0 I N C O M I N GI N SPEC T I O N PO R T F I T T I N G / T ov e r i fy p o r ts m a d eto p r i n tF a i l t o i d e n t i f y d a m a g e dp o rtPo o r Pri n t b i l i t yPo o r g a g ePl a c e m e n t W e l d i n gp ro c e s s f a i l u reSe a l i n g p ro c e s sf a i l u reF u c t i o n t e s t i n f a i l u re815 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 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 the 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 effectiveness 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. 16 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 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 17 Process Causes Process FMEA considers process variability due to: OPERATOR SETUP MACHINE METHOD ENVIRONMENT MEASUREMENT 18 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 RR Sampling Testing DOE 19 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 failure mode Typically, three items are scored: 20 Risk Priority Number RPN = O x S x D Occurrence x Severity x Detection O S D x x = RPN 21 Shortings of RPN A 8 4 3 96 B 4 8 3 96 SAME RESULT 22 E f f e ct C r i t e r i a : S e v e r i t y o f E f f e ct D e f i n e d R a n ki n gH a z a r d o u s:W i t h o u t W a r n i n gM a y e n d a n g e r o p e r a t o r . F a i l u r e m o d e a f f e ct s sa f e v e h i cl e o p e r a t i o n a n d / o ri n v o l v e s n o n co m p l i a n ce w i t h g o v e r n m e n t r e g u l a t i o n . F a i l u r e w i l l o ccu r W I T H O U Tw a r n i n g .10H a z a r d o u s: W i t hW a r n i n gM a y e n d a n g e r o p e r a t o r . F a i l u r e m o d e a f f e ct s sa f e v e h i cl e o p e r a t i o n a n d / o ri n v o l v e s n o n co m p l i a n ce w i t h g o v e r n m e n t r e g u l a t i o n . F a i l u r e w i l l o ccu r W I T Hw a r n i n g .9V e r y H i g hM a j o r d i sr u p t i o n t o p r o d u ct i o n l i n e . 1 0 0 % o f p r o d u ct m a y h a v e t o b e scr a p p e d .V e h i cl e / i t e m i n o p e r a b l e , l o ss o f p r i m a r y f u n ct i o n . C u st o m e r v e r y d i ssa t i sf i e d .8H i g hM i n o r d i sr u p t i o n t o p r o d u ct i o n l i n e . P r o d u ct m a y h a v e t o b e so r t e d a n d a p o r t i o n( l e ss t h a n 1 0 0 % ) scr a p p e d . V e h i cl e o p e r a b l e , b u t a t a r e d u ce d l e v e l o fp e r f o r m a n ce . C u st o m e r d i ssa t i sf i e d .7M o d e r a t eM i n o r d i sr u p t i o n t o p r o d u ct i o n l i n e . A p o r t i o n