过程失效模式分析P F M E APFMEAP F M E A:/:///.A B C. ..,,.(. )( /)(())109 87 6 5 4 32 110 9 8 7 6 5 4 3 2 110 9 8 7 6 5 43 2 1/100 , 1000X,,:/50 , ,, 1000 10001000 1000 1000 1000 10001000 XXXX100% 1,/ //( )20 10 5 :. , (100%),0.5-1, , //( 100%),, S P C( )., , ,X XXXX0.5/100% ,,:2 X X X X X100%//// ., , (,1 (75%)100%)(),:..( 100%) ,0.5 0.1 , , 50%,:( 100%) , ,(25%):/0.01 , 1000: A =· B =· C =P R O C E S S F M E ASuggested PF M E A Severi ty Evaluat ion Cr i te r iaSugges ted PFMEAOccur rence Eva l ua t i on C r i t e r i aSuggested PF M E A Detect ion Evaluat ion Cr i ter iaCri ter ia : Sever i ty o f Ef fec t : Th is rank ing r esul ts when a potent ia l fa i lu re mode resu l ts in a f ina l custo mer and/or manufactur ing/asse mbly p lant defect . The f ina l custo mer should a lways be cons idered f i rs t . I f both occur , use the h igher o f the two sever i t ies .Probabi l i tyEf fectR anking Like ly Fa i lure Rates R ankingD etect ionCri ter iaA B C Suggested Range o f Detect ion Methods R ankingof Fa i lure(Custo mer Ef fec t )(Manufactur ing/Asse mbly Ef fec t ) Very h igh sever i ty rank ing when apotent ia lfa i lu re mode af fec ts safe vehic le operat ion and/or invo lvesnonco m pl iance wi th govern ment regula t ion wi thout warn ing. AbsoluteH azardous wi thout Or may endanger operator (machine orasse m bly) wi thout warn ing.100 per thousand Al most Imposs ib le cer ta in tynon- ofdetect ion.10 910 910 9X C annot detect or is not checked.piecesW arningVery High: Pers is tent fa i lu resVery h igh sever i ty rank ing when apotent ia lfa i lu re mode af fec ts safe vehic le operat ion and/or invo lvesnonco m pl iance wi th govern ment regula t ion wi th warn ing. H azardous wi th C ontro ls wi l lOr may endanger operator (machine orasse m bly) wi th warn ing.C ontro l is ach ieved wi th ind i rec t orrando m checks on ly .50 per thousand p iecesVery Re m oteprobably not detect . XW arningOr 100% o f product may have to be scrapped, or veh ic le /i tem repai red in repai r depar tmentC ontro ls Vehic le /i tem inoperable (loss o f pr imary funct ion). C ontro l is ach ieved wi th v isual inspect iononly .8 78 78 7Very HighHigh 20 per thousand p ieces10 per thousand p iecesR e m ote have poor chance of C ontro ls XX High: Or product may have to be sor ted and a por t ion (less than 100%) scrapped, or vehic le /i tem repai red in repai r depar tment wi th a repai r t ime between hal f an hour andFrequent fa i lu resVehic le /i tem operable but a t a reduced leve l o f per formance. C usto mer very d issat is f ied.have poor chance of detect ion.C ontro lis ach ieved wi th double v isua l inspect ion on ly .Very LowOr a por t ion (less than 100%) o f theVehic le /i tem operable but co mfor t / p roduct may have to be scrapped wi th no C ontro l is ach ieved wi th char t ing m ethods, such as SP C (Stat is t ica l Process Cont ro l ).C ontro ls maydetect .666M o derateconvenience i te m(s) inoperable . C usto mer d issat is f ied. sor t ing, or veh ic le /i tem repai red in repai r depar tment w i th a repai r t ime less than hal fan hour . 5 per thousand p iecesLo wX XVehic le /i tem operable but co mfor t / Or 100% of product may have to be convenience i te m(s) operab le reworked, or veh ic le /i tem repai red o f f -l ine at a reduced leve l o f per formance. but does M o derate :O ccasional fa i lu resC ontro l is based on var iab le gauging af ter par ts have le f t the s ta t ion, O R G o/No Go gauging per formed on 100% of the par ts a f ter par ts have le f t the Error detect ion in subsequentC ontro ls maydetect .5 45 45 4Lo w2 per thousand p ieces1 per thousand p iecesM o derateX X XXC usto mer so me what d issat is f ied. Fi t & f in ish/squeak & ra t t le i temdoes not conform. Defect not icedby most custo mers (greater than75%).not go to repai r depar tment . C ontro lsOr the product may have to be sor ted, wi thno scrap, and a por t ion (less than 100%)reworked.have a good chance to detect .operat ions,O R gauging per formed on setup and f i rs tp iece check (for setup causes on ly).Very LowM o derate ly HighError detect ion in-s ta t ion, O R error detect ion in subsequent operat ions by m ul t ip le layers o f acceptance: supply , select , ins ta l l ,ver i fy . Can not accept discrepant par t .C ontro ls Fi t & f in ish/squeak & ra t t le i tem does not conform. Defect not iced by 50% of custo mers.Or a por t ion (less than 100%) o f theproduct may have to be reworked, w i th no scrap,on-l ine but out -o f -s ta t ion.have a goodchance to detect .333Minor0.5 per thousand p ieces0.1 per thousand p iecesHighX XXLo w:R elat ive ly few Fi t & f in ish/squeak & ra t t le i temdoes not conform. Defect not icedby d iscr iminat ing custo mers (lessthan 25%). C ontro lsalmost fa i lu resOr a por t ion (less than 100%) o f theproduct may have to be reworked, w i th no scrap, on l ine but in -s ta t ion.Error detect ion in-s ta t ion (auto mat icgauging wi th auto mat ic s top 2 12 12 1Very MinorN oneVery High Very High XX cer ta in todetect . feature).Can not pass d iscrepant par t .R e m ote: Fai lure is unl ike lyC ontro ls cer ta in to detect . Discrepant par ts can not be madebecause i te m has been er ror proofed byprocess/ product des ign.Or s l ight inconvenience to operat ion or operator , or no e f fec t .0.01 per thousand piecesN o d iscern ib le e f fec t .Inspect ion Types: A = Error Proofed · B = Gauging · C = Manual Inspect ion。
