Surface Roughness Statistic Models of Metallized Coatings in Grinding Manufacturing System

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1 Mihiel Iliecu nd Mihne Cotoiu Surfce Roughne Sttitic Model of Metllized Coting in Grinding Mnufcturing Sytem MIHAIELA ILIESCU, MIHNEA COSTOIU Mnufcturing Deprtment POLITEHNICA Univerity of Buchret Spliul Independenţei no. 33 Street, Contntin Mille, no. 5 Street ROMANIA iomi@clicknet.ro, m_cotoiu@rectort.pub.ro Abtrct: - Metllizing proce h known continuou extent, ltely, becue of the pryed coting intenive ppliction into vriou indutril field. Metllized coting hve very importnt wer or, corroion reitnce chrcteritic nd, when ued for repiring worn prt, the precribed urfce ulity pecifiction cn be obtined only by grinding, fter therml prying. Sttitic model of grinded urfce roughne re ueful, pecilly, for optimizing the mchining proce. For deute nd, fter meurement, LbVIEW dt cuiition ytem w ued to obtin grinded urfce roughne vlue nd, for obtining ttiticl model needed, pecilized regreion oft-wre w conidered. Key-Word: - metllized coting, urfce roughne, experiment deign, regreion nlyi, ttitic model Introduction Metllized coting i lmellr multilyer metllic tructure creted by metllizing proce. The therml pry or metllizing proce cn be decribed [] the proce where pure or lloyed metl i melted in flme nd tomized, by blt of compreed ir into fine pry. The pryed molten prticle, trike [7], t high velocity, previouly prepred urfce, of the prt, where they fltten out, cool, lmot intntly, nd build up on one the other. So, multilyer, lightly porou tructure, i generted. When the pryed prticle trike the urfce, it fltten nd cool, nd, o it contrct, reulting in reidul tree. By building the multilyer coting, thee tree um up nd, o, permnent tenile tree re there, into the exterior coting lyer, while, compreive tree re into the interior coting lyer. Tht why, when metllizing nd/or mchining thee tructure, cution i necery, to void coting frcture. A, mot of the metllizing procee ue ir to pry the molten metl nd, uully, they tke plce in norml tmopheric condition, chemicl interction pper. So, in metllized coting, there cn be noticed, next to pryed metl prticle, oxide nd crbide incluion, outlining the grin of prticle boundry. The bond of metllized coting prticle to the prt mteril i phyicl mechnicl one, obtined by: cermeting the prticle into the urrounding oxide; by welding micro-point; by mechnicl nchoring onto the roughne of the impct urfce. Mteril ued in prying re, powder or wire nd, with vriou chemicl compoition, depending on their finl ue (wer reitnce, corroion reitnce, lubricting etc.). Conidering the tinle teel, they cn be divided into hrd or mild one nd, of coure, the more evere wering condition in uing, the higher coting hrdne, needed. Among widely ued Romnin mteril, wire form, there re 4C3 nd MET4 which, metllized, provide hrd coting with very good mechnicl chrcteritic. The metllogrphic tructure [3] of the therml pryed hrd teel, 4C3 nd MET 4, re hown in Figure nd, repectively, Figure. A obervtion, it i mentioned the fct tht pryed coting propertie re, completely, different from the initil mteril one. Fig. Metllogrphic tructure of 4C3 metllized coting ISSN: Iue 9, Volume 7, September 8

2 Mihiel Iliecu nd Mihne Cotoiu Metl Fig. Metllogrphic tructure of MET 4 metllized coting G or Air Therml Spry Gun Energy Molten Mteril Multilyer Coting Previouly Prepred Subtrte Prt A cheme of the metllizing proce i preented in Figure 3. One cn notice tht for metllizing proce there mut be n energy ource (combution flme, electric rc, plm) for heting powder or wire form mteril to molten or ner-molten tte nd g (uully, compreed ir) to propel the mteril towrd the trget ubtrte. Mot of the time, pecilly when wer reitnce or, lubricting chrcteritic re reuired, in order to obtin precribed geometric preciion of the prt, mchining of the metllized coting i necery. Thee multilyer tructure, dherent to the be mteril, re porou, with high hrdne nd reuire pecil mchining condition [*]. A, both 4C3 nd Met 4, re hrd teel, grinding i often ued, either fter initil turning or, one nd only mchining procedure (conditioned by the retriction tht the pryed coting doe not differ much from the finl precribed hpe, dimenion etc. of the prt). or Fig. 3 Metllizing proce cheme One importnt geometricl preciion prmeter, i the urfce roughne nd, pecilly when lubricnt re ued, ply very importnt role in functionl chrcteritic of the product which metllized prt belong to. The pecific Reference [], [7] preent only generl informtion on grinding procedure mening grinding type wheel, ome vlue of the mchining prmeter nd of poible obtinble urfce roughne. There re poor untittive dt of urfce roughne dependence on ny, of the grinding prmeter nd, rrely include Romnin mde tinle teel. Sttiticl Modeling Conidering ll the bove mentioned, the reerch objective w to determine ttiticl model of urfce roughne dependence on grinding prmeter - for 4C3 nd MET4 metllized coting. The mentioned objective w reched by following the reerch direction: - etblihing the pproprite reerch method; - determining the regreion function; - pointing out the influence of grinding prmeter; - recommendtion for n pproprite ctive control grinding mnufcturing ytem. Reerch methodology [], [4] i vt but, for the propoed objective, w bed on the fct tht proce tht i on within certin technologicl ytem, cn defined by vrible connected through reltion : Y = Γ( x, x,..., x j,..., x n ) () clled proce function; where: x j, j =,,., k repreent the independent proce vrible (controllble input); Y the dependent proce vrible (output); Γ - the type of dependence reltion. Before determining optimum Γ type function, there mut be etblihed the dependent nd, mot of ll, the independent vrible tudied, their vlue nd vrition field nd, not the let, the experiment tructure (deign of experiment) tht fit bet. Bed on the bove mentioned, reerch w crried on the controllble input, x j : - prt rottionl peed, v p [m/min]; - longitudinl feed peed, l [mm/min]; - trnverl peed, t [mm/d.c.], where d.c. refer to double coure of the grinding mchine plteu; - micro-hrdne, HV.5. ISSN: Iue 9, Volume 7, September 8

3 Mihiel Iliecu nd Mihne Cotoiu Contnt input were conidered to be ; - environment chrcteritic (temperture, humidity) - grinding wheel chrcteritic (mteril, dimenion) nd cooling fluid propertie. Uncontrollble (noie) input: - vibrtion of the technologicl ytem - for exterior cylindricl grinding. The output, Y, w urfce roughne, evluted by R [μm] prmeter. For the regreion nlyi to be crried out, the controllble input vlue hd be conidered both, rel one, x j, well the coded one, z j ee Tble. There were conidered two three level experiment deign, one, frctionl fctoril - with 6 run, clled P. nd, the other, centrl compoite- with 8 run, clled [6] CCD, both deling with three independent vrible, x j. There w, lo, pplied nother frctionl fctoril deign, with run, deling with four independent vrible, clled [3] P.. Their tructure i preented in tble. The oftwre ued for regreion nlyi were REGS [3] with 3 replicte for Frctionl Fctoril Deign, nd DOE KISS [], [5] with 5 replicte for Centrl Compoite Deign. Controllble input vlue Tble v p [m/min] l [mm/min] t [mm/d.c.] Coded vlue (-) () () (-) () () (-) () (),5 4,43 8, Rel vlue, for P. deign 7 4,3,,3 Frctionl Fctoril Deign (P.) Centrl Compoite Deign (CCD) Frctionl Fctoril Deign (P.) Tble Experiment Deign Run x x x Run x x Run x x x 3 x Rel vlue, for CCD deign,5 4,8 8, 8 4 -,5 - Added independent vrible, for P. deign (-) () () - coded vlue rel vlue The regreion nlyi, crried out with REGS progrm, provide function of type: or 3 3 Y = x x x () Y = x x x x (3) The regreion function [5] determined with DOE KISS i polynomil type: k k k k Y = + i zi + ij zi z j + ii zi (4) i= i= j= i+ i= ISSN: Iue 9, Volume 7, September 8

4 Mihiel Iliecu nd Mihne Cotoiu Ob. Reltion () nd (3), by logrithm, re imilr to reltion (4) except for the fct tht there re, only, firt order polynomil fctor, with no interction or econd order one included. 3 Experimentl reerch Reerch h been done nd, the experimentlly obtined reult were ued in order to determine reuired ttiticl model. 3. Experiment Experiment were crried out on electric rc therml pryed hrd teel, 4C3 nd MET 4, whoe initil (wire form) chemicl tructure i preented in Tble 3 nd the electric rc metllizing proce prmeter re hown in Tble 4. Fig. 4 Metllizing proce Mteril Tble 3 Chemicl tructure nd mechnicl propertie Chemicl Structure HV.5 Poroity Wire Dimeter [% vol ] [mm] 4C3,4 % C, (3 3,) % Cr φ ±,4 MET 4 (4 5) % Cr, (,4,5) % C φ,8 ±,4 Fig. 5 Prepred mple for grinding experiment Mteril Electric Arc Voltge [V] Metllizing proce prmeter Electric Current Intenity [A] Metllizing Ditnce [mm] Tble 4 Compreed Air Preure [br] 4C MET The therml pryed coting were pryed on the exterior cylindricl urfce of previouly prepred mple. Figure 4 preent n imge tken while the metllizing proce w on. One cn ee tht the prt to be pryed i clmped onto lthe, hving rottionl movement nd, the longitudinl movement i tht of the prying gun. Additionl preprtion of mple w necery, mening the zone ubmitted to vriou grinding prmeter, were eprted to one nother by rough turning, to llow the cce of the grinding wheel. A mple, prepred for reuired experiment i hown by Figure 4. Once grinding experiment over, in concordnce with the reuired experimentl progrm, there were meured roughne vlue of the generted urfce. The meuring pprtu w Rugom type one nd, for fter nd more precie meurement, LbVIEW dt cuiition ytem w, lo ued. Thi ytem llowed, meurement/ec., for 6 econd ech, nd meurement were tken in 5 different point of the generted urfce, o tht every experience reult were checked out. The tructure of thi cuiition ytem, llow the clculu of medium urfce roughne vlue ee Figure 6 An imge of, thu obtined, urfce roughne profile i preented in Figure 7. It cn be the cut off vlue (mrked by n rrow). Thee vlue refer to the moment (point) when Rugom meuring bll point got into the exiting urfce pore. The dt cuiition progrm tructure utomticlly remove thee vlue from the one conidered fit to determine rithmetic medi. ISSN: Iue 9, Volume 7, September 8

5 Mihiel Iliecu nd Mihne Cotoiu Frctionl Fctoril Deign (P.) Tble 5 Experimentl Vlue 4C3 MET 4 Run R [μm] R [μm].,5,67.,4,57 3.,77,87 4.,37,5 5.,48,64 6.,5,68 Fig. 6 LbVIEW progrm for obtining medium vlue of urfce roughne meurement Centrl Compoite Deign (CCD) 4C3 MET 4 Run R [μm] R [μm] Frctionl Fctoril Deign (P.) 4C3; Run MET 4 R [μm] Fig. 7 Surfce roughne meured profile Thu, the experimentlly obtined vlue, the one tht re conidered for regreion nlyi, re hown in Tble 5. ISSN: Iue 9, Volume 7, September 8

6 Mihiel Iliecu nd Mihne Cotoiu 3. Sttitic Modeling There h been crried out regreion nlyi nd, when uing REGS progrm, the pecific clculted prmeter were, follow: - regreion coefficient vlue; - ignificnce untifier (how if the independent tudied vrible h ignificnt influence on the output); - deucy untifier (how if the model i deute). All of bove mentioned obtined vlue re preented in Tble 6. So, there were obtined the ttitic model, of grinded urfce roughne metllized coting for: - 4C3 pryed mteril R = v p l t [μm] (5) - MET 4 pryed mteril R =.978 v p l t [μm] (6) For the independent vrible, x j, hving ignificnt influence on the dependent vrible, y, it i necery tht it ignificnce untifier, R j, h vlue tht, t let, eul.. A noticed, from Tble 6, the ignificnce untifier for trnverl peed, t, h vlue lower thn. which men tht thi controllble input doe not ignificntly influence the urfce roughne vlue. Bed on the bove, it h been conidered ueful further reerch on the influence of the other two controllble input, prt rottionl peed, v p, nd longitudinl feed peed, l, on the output vrible, urfce roughne, R. The regreion nlyi w done with DOE Ki oftwre, nd the obtined reult, for both 4C3 nd MET 4, re preented in Figure 8. The ttitic model re follow, for: - 4C3 pryed mteril R =.536.6x.x +.33xx +.8x +.7x (7) - MET 4 pryed mteril R =.67.7x.5x +.33xx +.8x +.7 x v p x = ; = l where: 6.6 (8) x (9) REGS regreion nlyi reult 4C3 Tble 6 Regreion Coefficient Significnce Quntifier R R R R Adeucy Quntifier, R *.973 j Quntifier v p v p mx l mx t mx = = = l t v p min l t min min MET 4 Regreion Coefficient Significnce Quntifier R R R R v p Adeucy Quntifier, R *.968 j Quntifier v p mx l mx t mx = = = l t v p min l t min min Ob.:. A fctor i conidered to hve ignificnt influence on the output long the P ( Til) vlue i le. or eul, to,5.. The econd order fctor of the input vrible, v p nd l, do not hve ignificnt influence on R prmeter. 3. Bed on the bove, the reltionhip (7) nd (8) turn into: R =.64.49v p.45l +. v p l [μm] nd, repectively, () R =.77.43v p.44l +. v p l [μm] () Uing DOE KISS, it cn be plotted the Preto Chrt of coefficient, tht point the influence of input vrible, on the output vrible i. 3 3 ISSN: Iue 9, Volume 7, September 8

7 Mihiel Iliecu nd Mihne Cotoiu 4C3 pryed mteril MET 4 pryed mteril Fig. 8 DOE KISS -regreion nlyi reult ISSN: Iue 9, Volume 7, September 8

8 Mihiel Iliecu nd Mihne Cotoiu - 4C3 pryed mteril - MET 4 pryed mteril Fig. 9 Preto chrt of coefficient It conider, both, ech independent vrible nd their reciprocl interction for their influence on the dependent vrible ee Figure 9. Thi oftwre, DOE KISS, lo provide n Expert Optimizer ee Figure, tht et the input vlue to minimize exit vlue 4C3 pryed mteril MET 4 pryed mteril Fig. Expert optimizer ISSN: Iue 9, Volume 7, September 8

9 Mihiel Iliecu nd Mihne Cotoiu R [um],9,8 MET 4,7,6,5 4C3,4,3, v p = 4.8 m/min, l [mm/min] REGS regreion nlyi reult 4C3 nd MET 4 Tble 7 Regreion Coefficient Significnce Quntifier R R R R 3 R Adeucy Quntifier, R *.955 j Quntifier v p v = v p mx p min l = lmx lmin t = tmx tmin 3 4 HVt mx HV = HV tmin R [um],8,7 MET 4,6,5 4C3,4,3, l = 8 mm/min, 5 5 vp [m/min] So, experiment were crried out, uing the P. Full Fctoril Deign (ee Tble ), the reult obtined (ee Tble 5) nd ttiticlly nlyzed with REGS progrm. ee Tble 7. The ttiticl model determined i: R = 7.43 v p l t HV nd, knowing tht n imge i much more uggetive thn, word, there re preented ome grph of R prmeter vrition ee Figure 3 nd Figure 4. [μm] () Fig. Grph of urfce roughne, R,vrition on grinding mchining prmeter,9,8,7 HV.5 = 37 Some grph, correponding to model determined by reltion () nd () re preented in Figure. Studying the rel itution, well the experimentlly obtined reult, it h been conidered of interet to ttiticlly determine, if, the pryed mteril chrcteritic, do influence urfce roughne. Becue one importnt pryed coting chrcteritic i repreented by their hrdne, thi one w conidered nother independent vrible, in ttiticl determining the mthemticl model of R urfce roughne prmeter. R [um],6,5,4,3,, t =. mm/d.c; v p =.43 m/min l [mm/min] HV.5 = 78 Fig. 3 Grph of urfce roughne, R,vrition on grinding mchining prmeter, HV hrdne conidered ISSN: Iue 9, Volume 7, September 8

10 Mihiel Iliecu nd Mihne Cotoiu R [um],8,7,6,5,4,3,, t =. mm/d.c; v p =.43 m/min; l = 7 mm/min HV.5 Fig. 4 Grph of urfce roughne vrition on pryed coting HV.5 hrdne 4 Concluion Therml prying proce, the propertie of the metllized coting, their mchining proce nd the ulity of the finl tructure, thu obtined, re ubmitted to continuou cientific nd technologicl reerch. One importnt mchining procedure, uully ued in order to obtin prt pecified geometricl preciion chrcteritic, i grinding. In order to tudy the ulity of thee multilyer tructure, referring to urfce roughne fter grinding, there hve been determined multivrible regreion [] [] H. S. Inghm, A. P. Sheprd, The METCO function. They were obtined by uing pecil Metllizing Hndbook, Long Ilnd City, New theoreticl nd experimentl reerch progrm. The York, 979. vrition rnge nd vlue of independent vrible conidered were preciely etblihed. Regreion nlyi, performed with REGS progrm, pointed out tht ll ttiticl model were deute nd, the tronget influence on urfce roughne w tht of longitudinl peed feed, l. The vrible tht did not ignificntly influence the R prmeter w the trnverl peed, t Regreion nlyi, performed with DOE KISS oftwre, conidered only the two mot importnt vrible tht influence R prmeter, it reulted from REGS regreion nlyi. Thi DOE KISS oftwre howed the deucy of ttiticl obtined model nd the influence on urfce roughne of the tudied vrible, well one of their interction. For, both, mteril tudied, the ttitic model were imilr, mening there were the me fctor tht did, ignificntly, influence grinded urfce roughne vlue. A nticipted, from experience, the gretet influence w tht of longitudinl feed peed, l. When tudying the micro-hrdne metllized lyer chrcteritic, it proved out (from regreion nlyi) tht it i vrible with high influence on R prmeter vlue, the econd, importnce. One mjor deficiency of the determined regreion function i their limited ppliction only to the tudied metllized coting, 4C3 / MET 4 nd grinding wheel couple. Alo, the deucy of regreion model reult i gurnteed, for the vlue of independent vrible within the conidered vrition rnge but, it lo, cn be ued for vlue not o fr do the limit conidered Mybe, the mot importnt ppliction of the determined ttitic model i their future ppliction to n utomted ctive control ytem. It men tht, once ettled the input vrible vlue, the grinded coting urfce roughne i permnently meured nd, if, it vlue re not the expected one, by feed-bck loop, there hould be commnd to the grinding mchine ytem. A reult, either the longitudinl feed peed, l, or prt rottionl peed, v p, would be djuted o tht, the optimum R prmeter vlue, of the grinded coting could be obtined. Reference: [] Bognr, C, Sotome O, A Method for Byein Met-Inference Applying Multiple Regreion, th WSEAS Interntionl Conference on Sytem, Herklion, Greece, July, 8, pp [3] [3] Iliecu, M., Reerch on Qulity nd Mchinbility of Therml Spryed Coting, Doctorl Thei, Buchret, Romni,. [4] Norini A, Zinodin J, Nigel J, Volumetric Stem Biom Modeling Uing Multiple Regreion, th WSEAS Interntionl Conference on Applied Mthemtic, Ciro, Egypt, December, 7, pp [5] Rbi Akt Altin A, J, Nigel J, A generting Function nd Some Recurrence Reltion for Fmily of Polynomil, th WSEAS Interntionl Conference on Applied Mthemtic, Ciro, Egypt, December, 7, pp 8-. [6] Schmidt, L., et l., Undertnding Indutril Deigned Experiment, Acdemy Pre, Colordo, USA, 5. [7] 6. ISSN: Iue 9, Volume 7, September 8