FMEA Methodology for Quality Improvement in Sheet Metal Industry

Transcription

1 FMEA Mthodology for Quality Improvmnt in Sht Mtal Industry Vitthal Jumbad Dr. Babasahb Ambdkar Marathwada Univrsity, Lturr Maharashtra Institut of Thnology, Pun, Maharashtra Satput M. A. Lturr, Maharashtra Institut of Thnology, Aurangabad, Maharashtra J. J. Salunk, Asso. Prof. Dogiri Institut of Enginring and Managmnt Studis Aurangabad, Maharashtra Abstrat - Evry automobil industry is striving for growth in today s omptitiv world and for that ah brand is dvloping nw thniqus and tools to dlivr dft fr produts to th ustomr at minimum ost. Failur mod fft analysis (FMEA) is on of th fftiv doumntd tools usd in vry automotiv industry to avoid dfts in dsign or manufaturing of th produt. This FMEA whn applid to pross of th prodution thn it is alld as Pross Failur Mod and Efft analysis. PFMEA is th intgral standard doumnt of all automotiv ompanis in th world. This was dvlopd first tim by NASA in 1960 for Apollo projt to avoid any aidnt of spaship in spa and on arth. Aftr that it was dvlopd for automobil industris and today vry automotiv industry is using it as a standard tool. An FMEA is analytial thniqu mployd by a tam as a mans to assur that, to xtnt possibl, potntial failur mod and thir auss hav bn onsidr and addrss. This papr will giv a brif viw of ruls and flow of FMEA to apply it in sht mtal industry. Kywords: Failur mod fft analysis (FMEA), Risk priority numbr (RPN). I. INTRODUTION An FMEA is a doumnt inludd in quality rquirmnt of automotiv OEMs for thir supplir. Som supplir stablishs th standard produr to prpar FMEA in a format and is always availabl with thm. Prparation of FMEA is a tam work and is a bfor an vnt doumnt. Th purpos of FMEA is to build a rigid and fftiv quality improvmnt systm to produ high quality and rliabl produts [1]. FMEA is a tam orintd quality tool usd to prdit th possibl failur mods, thir ffts and auss in th dsign and manufaturing prosss [2]. On of th most important fators for th sussful implmntation of an FMEA is timlinss. An FMEA is mant to b a bfor-th-vnt ation, and not an aftr-thfat xris. To ahiv th gratst valu, an FMEA must b don bfor a dsign or pross is onvrtd into a produt. An FMEA an rdu or liminat th han of implmnting a orrtiv hang that would rat an vn largr onrn. R.S.Mhtr t al. [2] hav onsidrd FMEA in a Prision sht mtal ompany for bnding pross. Thy hav usd Ishikawa diagram for root aus analysis of sht mtal bnding pross problms and implmntd FMEA produr sussfully. M.Dudk-Burlikowska[] hav suggstd intgration of quality managmnt and quality ontrol systm for suss of ompanis. An FMEA is a strong tool whih an hlp ompanis to improv th produt quality. H. Arabian-Hosynabadi t al. [] hav implmntd FMEA for diffrnt failur mods of wind turbin lik mhanial failur, ltrial failur and matrial failur. Raksh R. t al. [5] hav also implmntd FMEA in lif ar produt manufaturing industry to rdu th brakdown of sub systm omponnts. II. DEFINITION OF FMEA Failur Mod & Effts Manual (FMEA) is on of th QS-9000 Quality Systms Rquirmnt Supplmnt s. An FMEA an b dfind as a systmatizd group of ativitis intndd to rogniz and valuat th potntial failur of a produt / pross and its fft, idntify ations whih ould liminat or rdu th han of th potntial failur ourring, and doumnt th pross III. TYPES OF FMEA FMEA an b don in diffrnt stags of produt lif yl and an b lassifid as follows: 1. onpt FMEA (FMEA) 2. Dsign FMEA (DFMEA). Pross FMEA (PFMEA). Mahinry FMEA (MFMEA) onpt FMEA is don during th onpt building stag so that all potntial failur mods in onpt dsign an b addrssd with ation. Dsign FMEA is don bfor atual dsign phas of th produt so that all dsign failur mods an b addrssd prior to dsign issus and ation an b finalisd. Pross FMEA is don aftr finalising dsign and bfor prodution run so that all manufaturing pross failur mods and ation an b listd out. Mahinry FMEA is don for th mahin parts failur mods and listd out with ation to b takn bfor it gos for prodution. 122

2 IV. PURPOSE OF FMEA 1. To idntify potntial failur mods with svrity ranking, that may advrsly afft safty, govrnmnt rgulation omplian or ustomr satisfation. 2. To idntify ritial haratristis & signifiant haratristis.. To hlp Enginrs fous on liminating produt and pross onrns and hlps to prvnt problms from ourring.. Idntify potntial dsign dfiinis bfor rlasing hardwar to prodution. 5. To idntify potntial pross dfiinis bfor prodution bgins and ranking all failur mods. V. WHO PREPARES FMEA? Th tam approah to prparing FMEAs is rommndd. Although rsponsibility for th prparation of th FMEA must, of nssity, b assignd to an individual, FMEA input should b a Tam ffort. A Tam of knowldgabl individuals should b assmbld:.g., Enginrs with xprtis in dsign, manufaturing, assmbly, srvi, quality, and rliability. Th rsponsibl Systm, Produt or manufaturing / assmbly nginr lads th FMEA Tam. Th rsponsibl dsign or pross nginr is xptd to involv rprsntativs from all afftd ativitis. Tam mmbrs should inlud dsign, manufaturing, assmbly, quality, rliability, srvi, purhasing, tsting, th supplir and othr subjt mattr xprts as appropriat and th mmbrs will vary as th onpt, produt & pross dsigns matur. For propritary dsign and pross, supplirs ar rsponsibl. Supplir should handl rsptiv FMEA for produt and pross bfor first dispath. VI. FMEA FORMAT Format for FMEA onsists of numbr of olumns in whih appropriat information is to b filld. Abov th tabl ompany nam, part nam, dat of FMEA, rsponsibl nginrs and othr introdutory information is writtn. Itm / Pross Stp Funtion Failur Mod Efft(s) of Failur TABLE I FORMAT OF FMEA O D urrnt Rspons & S l R aus(s)/ Pross Rommndd Tragt a t P Mhanism(s) ontrols Ations omplt v s u N Of Failur Dat s r Prvnt Dtt Ation Rsults S O D R Ation E E P Takn V T N 1. Pross Stp/Funtion: This inlud opration nam. 2. Failur mod: Th failur of th rsptiv funtion is mntiond sond olumn.. fft of failur: Efft of failur mod is listd in third olumn of th format.. Svrity: Th sriousnss or how muh svr th fft of failur mod is listd in fourth olumn. 1- rating is givn to th potntial fft. Highr th svrity highr is th rank. 5. lass: In this olumn th produt or pross haratristis is mntiond as -ritial haratristis or S-Signifian haratristis. 6. aus of failur: Th root aus of failur mod is mntiond in sixth olumn. Ishikawa diagram or why-why analysis may b usd to find xat root aus.. Ourrn: Ourrn rating is mntiond with rspt to givn aus. 1 to rating is givn highr th ourrn of aus highr will b numbr. 8. urrnt Pross ontrol: It is th dsription of ontrol of th prosss whih ithr prvnt th failur mod or dtt th failur mod. 9. Dttion: It is masurd in ranking 1-. If failur mod is vry hard to dtt thn ranking is highr and if failur mod is asy to dtt its ranking is low.. Risk Priority Numbr (RPN): It is th final ranking of th issu to did th rquird ation. Highr RPN issus must hav wll prpard ation plan. RPN is th produt of Svrity (S), ourrn (O) and dttion (D). RPN=S*O*D 11. Rommndd ations: Whn th failur mods hav bn rankd by RPN, orrtiv ation should b first dirtd at th ritial itms. If for xampl, th auss ar not fully undrstood, a rommndd ation might b dtrmind by statistial dsignd xprimnt (DoE). Th intnt of any rommndd ation is to rdu th Svrity, Ourrn, and / or Dttion Ratings. VII. RANKING SYSTEM IN FMEA Th fft, aus and dttion of th problm ar rankd in th rang of 1 to. Lvl of th ranking indiats th ritiality of th issu and dids th priority of th ation. Th potntial failur mod having high risk priority numbr must b onsidrd first for prmannt orrtiv ation. 1. Ourrn ranking: Ourrn ranking is givn as pr th frquny of failur mod. Following tabl an b rfrrd for th ourrn ranking. 12

3 Tabl II Ourrn ranking ritria Frquny Possibl failur rats Ranking Vry high 0 pr thousands of itms 50 pr thousand itms 9 Frqunt 20 pr thousand itms 8 failur pr thousand itms Modrat 5 pr thousand itms 6 failur 2 pr thousand itms 5 1 pr thousand itms Low failur 0.5 pr thousand itms 0.1 pr thousand itms 2 Vry low 0.01 pr thousand itms 1 failur 2. Dttion Ranking: Th dttion ranking is givn on th basis of ability of th urrnt pross ontrol to dtt th possibl failur mod. Following tabl an b rfrrd for giving dttion ranking. Tabl III Dttion ranking ritria Dttion ritria Ranking Absolutly unrtain Pross ontrol is unabl to dtt problm Vry rmot Vry rar han of dttion 9 Rmot Rmot han of dttion 8 Vry low Vry low han of dttion Low Low han of dttion 6 Modrat Modrat han of dttion 5 Modratly hans of dttion of failur high mod is modratly high High High han of dttion Vry high Vry high han of dttion 2 Almost possibl Dttion is always thr 1. Svrity ranking: Svrity ranking is givn aording to th sriousnss of fft of th failur mod. Following tabl an b rfrrd for th svrity ranking. Tabl IV Svrity ranking ritria Efft ritria Ranking Hazardous without failur mod affts th safty norms involvs nonomplian with govrnmnt rgulations without Hazardous with Failur mod affts govrnmnt norms with Vry high Loss of primary funtion 8 High Prforman rdution and ustomr dissatisfation du to failur mod Modrat Itm is oprabl and ustomr dissatisfation 6 Low Itm is oprabl but ustomr is not omfort 5 Vry low Dft notid by 5% ustomrs Minor 50% of th ustomrs ar not omfort with failur mod Vry minor Lss than 25% of th ustomr notid th dft 2 Non No notiabl dft 1 VIII. ASE STUDY This as study is about prparation of pross FMEA for th sht mtal part. Th opration inluds blanking and piring opration of progrssiv di. Th pross FMEA was arrid out for blanking and piring pross. Th potntial failur mods for blanking and piring pross onsidrd from th prvious xprin. 1. Inoming matrial grad wrong: If supplir s dispathd pross is not fool proof thy may dispath wrong raw matrial. 2. Dnt and damags to sht: Wrong dsign of rak may rsult in matrial damag or matrial may gt damag during transportation.. Latral shifting of blank: At th tim of plaing blank in di th blank may b shift whih will rsult in inorrt dimnsions. For avoiding this loating pin nd b hkd.. Burr problm: If th di and punh laran is not propr it will rsult in burr at th dgs. Insuffiint utting for also lads to burr problm in blanking. Burr at th dgs and hols will rsult in fitmnt issu and may lad to downtim. 5. Inomplt piring opration: If utting for is not suffiint it will rsult in inomplt piring opration. 9 Prparation of PFMEA: All failur mods ar listd in tabl and thir auss and fft ar mntiond. 12

4 Tabl V Svrity ranking Th sriousnss of th problms is rankd as follows: Opration 1 Failur mod Efft Svrity Wrong matrial grad Not suitabl for furthr opration 2 Dnt and damag Rjtion Inomplt Rjtion piring Burr in piring Fitmnt problm 8 Blanking burr Fitmnt problm 8 Tabl VI Ourrn ranking Th frquny of th ourrn of th problm is rankd as follows: Opration aus Ourrn rating 1 Bad ontrol on insption 2 Bad pallts and handling 8 Low utting for Punh laran not ok 8 Di laran not ok 8 Tabl VII Dttion ranking Th pross ontrol ability of th dttion of th problm is rankd as follows. Opration Pross ontrol (Dttion) 1 Dispath rport 2 Visual insption 8 Visual insption 2 Visual insption 6 Visual insption 6 Dttion ranking Tabl VIII alulation of Risk Priority Numbr (RPN) Opration alulation of svrity (S*O*D) RPN 1 ** 6 2 8*8*8 512 **2 2 8*8*6 8 8*8*6 8 Highst RPN issu should b rsolvd immdiatly with prmannt orrtiv ation and rommndd ation should b mntiond on sht. Ths rommndd ation and all pross ontrol must b mntiond in th ontrol plan and standard oprating produr. IX. LINKAGE OF THE PFMEA WITH OTHER DOUMENTS Pross flow diagram Pross FMEA ontrol plan Standard oprating produr (SOP) Fig.1 Linkag of quality standard doumnts Th pross squn is listd in th pross flow diagram (PFD). From this PFD th failur mods of ah pross ar rordd in FMEA format as pr squn in PFD. Th pross ontrols and rommndd ations for rsptiv problms from FMEA ntrd in ontrol plan with sam opration squn as in PFD and thn th oprating produr is prpar as pr ontrol plan. In this way ah pross and its problm is intrlinkd through PFD, FMEA, ontrol plan and SOP. PFMEA ats as a onnting link btwn PFD and ontrol plan and SOP is th output of all ths thr doumnts. X. ONLUSION FMEA givs us th point of ation for any issu bfor an rror ours with th hlp of RPN numbr. This avoids furthr rwork and tim onsuming orrtiv ation. FMEA is a tam orintd tool usd to analys and valuat potntial failur mods of ah pross in dsign and manufaturing stag for th sht mtal parts. FMEA provids a standard mthodology for doumnting all ths failur mods, thir auss, fft, ontrol and ranking. Th aim of th FMEA is to improv th urrnt prodution pross for high quality and rliability of th produt. It is nssary for any automotiv industry to implmnt FMEA for striving in omptitiv markt and produing world lass produts. 125

5 XI. REFERENES [1] S.H.Tng and S.Y.Ho, Failur Mod and fft analysis: An Intgratd approah for produt dsign and pross ontrol, Intrnational Journal of Quality and Rliability Managmnt, Vol , pp [2] R.S. Mhtr and R.J.Dhak, Using Failur Mod Efft Analysis in a Prsion Sht Mtal Parts Manufaturing ompany, Intrnational Journal of Applid Sins and Enginring Rsarh, Vol. 1, 2, [] M. Dudk-Burlikowska, Appliation of FMEA mthod in ntrpris fousd on quality, Journal of Ahivmnt in Matrials and Manufaturing Enginring, Vol. 5, Issu 1 Marh [] Arabian H., Ora, Tanvr, P.J. (20), Failur Mod and Effts Analysis for wind turbins, Intrnational Journal of ltrial powr and nrgy systm, 2 ().pp [5] Raksh. R, Bobin hrian Jos, Gorg Mathw, FMEA Analysis for Rduing Brakdowns of a Sub systm in Lif ar Produt Manufaturing Industry, Intrnational Journal of Enginring Sin and Innovativ Thnology, Volum 2, Issu 2, Issu 2, Marh 201. [6] Y.M Dgu, R.S. Moorthy, Implmntation of Mahinry Failur Mod and Efft Analysis in Amahara Pip Fatory P.L..,Bahir Dar, Ethiopia, Amrian Journal of Enginring Rsarh Vol. 0, Issu-01, pp