Khảo sát ảnh hưởng của nồng độ bột titan trong dung dịch điện môi đến năng suất và chất lượng bề mặt gia công thép SKD61 bằng phương pháp tia lửa điện với điện cực đồng

Bdnh Tidn Long vd Dig Tap chi KHOA HQC & CONG NGHE 135(05): 161 - 166 K H A O SAT ANH H l T d N G CUA NONG D Q B Q T TITAN T R O N G DUNG DICH DIEN M O I DEN NANG SUAT VA CHAT L l / O N G BE M A T GIA CONG T H E P SKD61 BANG PHU'ONG PHAP TIA Ll^A DIEN V d l DIEN ClTC DONG Bdnh Tiln Long', Ngd Cud^g^ Nguyin Hiru Phdn*', Tr^n Quang Cong^ 'Trudng Dgt hoc Bach Ichoa Ha Np 'Truang Cao dang Kinh te - Ky thudt - DH Thdi Ngu ^Truang Cao dang Ca Ichi Luyen lam Thdt Ng TOM TAT Phuang phdp gia cong bang tia Ida didn (EDM) dugc img dyng rdt phd bidn cdng nghiSp ehd tao dyng cy, khuon mlu va hang khong Nghien ciiu ndng cao nang sudt va chdt lugng gia cong bang phuang phdp tia lua dien vi vdy co •} nghia thuc tien to Imi Bai bdo gidi thieu nghien Clhi vd dnh hudng cua nong dp bpt titan dung djch dien moi ddn lugng mdn cua dien cue (TWR), ndng suit bdc taeh vgt lidu(MRR) vd nhdp nho bd mat gia cong (RJ gia cong thep SKD6I bang phucmg phdp tia lira dien vdi di?n cyc ddng phan cue ngugc Kdt qua cho thdy, trpn hot titan vao dung dich dien mdi da lam giam lugng mon dien cue va tri s6 nhdp nho bd rngt, tang ndng suat boc taeh vgt lieu Tir khda: EDM, MRR TWR thepSKD61 bpt titan giam, giam chieu day ldp vat lieu be mat chi tiet bj dnh hudng nhiet [2], [5] Viec trgn cdc logi bdt Cu, Fe, Al va C vao dung dich dien mdi dd gia cdng thep vdi dien cue Id Cu da nang cao kha ndng danh thiing dien mdi, tdng ndng bgt thi nang sudt bdc tdeh tdng [5] Khi trgn bgt graphit vao dung djch dien mdi vdi ndng 4g/l da Iam khe hd phdng dien tdng didn dp phdng dien Igi giam, dn djnh ciia qua trinh gia cdng dugc ndng cao vd nang suat gia cdng tang 60%, lugng mdn didn cyc gidm 28% [6] Trdn bdt Si vao dung djch dien mdi de gia cdng thep SKD61 da nang cao dugc chdt lugng bd mat gia cdng [7] Khao sat vide trgn bpt Al vd bdt SiC vao dung djch dien mdi de gia cdng thep SKDI1 vd hgp kim Ti-AI-4V da cho kdt qua Id nang suat bdc tdeh vat lieu tdng va trj sd nham be mat gidm [8J Luc tdc ddng len be mat phdi giam dugc cho la nguyen nhan ddn Trong cdng nghg EDM viec su dung bdt kim ddn tri sd nhap nhd giam va lam tang bdng logi thich hgp trdn vao dung djch dien mdi se bd mat gia cdng trgn bgt Si vao dung djch lam giam dg ben each dien cua dung dich dien mdi [11] Anh hudng ciia viec sii dung di^n mdi va lam tang khe hd phdng didn giu"a bdt kim loai cdng nghe EDM ddn chat dyng cy - phdi [9], tu dd cdi thien ndng suat lugng be mat gia cdng cdn phu thudc vdo loai bdc taeh vat lieu vd chdt lugng bd mgt gia vgt lieu gia cdng: trgn bdt AI cd kich thudc cdng: ndng suat bdc taeh vat lieu tang, tri sd trung binh vdo dung dich didn mdi gia nham va cac vdt nut te vi tren bd mat gia cdng cdng thep SKH-51 da cho bdng bd mgt cao nhung gia cdng thep SKH-54 lgi nhan ' Tel: 09S3 7S3844 Email- Phankicn@gmall.com DAT VAN DE Gia cdng bang tia lua dien (EDM) id phuong phdp gia cdng khdng truydn thdng dugc sii dung phd bidn de gia cdng cac logi vgt lieu ddn dien khd gia cdng hoac cd hinh dgng bd mat phurc tap Mac dii cd nhidu uu didm (khdng gay bien dang tren chi tidt gia cdng; rung ddng, dng suat co hoc, tidng dn khdng xuat hien sudt qua trinh gia cdng ) nhung phuang phdp lgi tdn tai mgt sd nhugc diem ca bdn lam han ehd khd ndng ling dyng ciia nd nhu: ndng suat gia cdng thap, chat lugng be mat sau gia cdng khdng cao [4] Mgt sd kdt qua nghien ciru gan day cho thay, vide trdn bgt kim loai hodc hgp kim vao dung djch dien mdi ciia qua trinh gia cdng tia Ilia didn Id mgt giai phap kha thi de khde phuc nhiing han ehd tren 161 Banh Tien Long vd Dtg Tap chi KHOA HQC & C N G NGHE 135(05): 161-166 thuat Cdng nghiep Thai Nguyen Vat lidu mdu dugc dp bdng bd mat thdp [7] Khdo sat chat thi nghiem la thep SKD61 (TC JIS - Nhgt lugng bd mgt cua thep SKDll gia cdng Ban) nhiet luygn dgt ciimg HRC = (48-^52), bdng EDM cd n-gn cdc logi bdt Al, Cu, Cr va mau cd kich thudc 45x27x5mm Vgt !i?u didn SiC vdo dung dich dien mdi cho thay: chat cyc dyng cu la dong Cl 100 (99,9%) cd dudng lugng gia cdng bj dnh hudng dang ke bdi kinh 25mm, sd lugng 10 chiec Bgt titan cd ndng dg, kich thudc, khoi lugng rieng, dien kich thudc cd hgt 45 pm dugc lya chgn dd trd vd ddn nhidt ciia bdt; vdi ndng dg bgt trgn dung djch dien mdi Dung djch khdng ddi thi nang suat bdc tdeh vat lieu se dien mdi Id dau bien the HD-1 ciia Hdng dat cao nhdt kich thudc bdt nhd nhdt Trj ELECTROL Duy tri sy ddng ddu vd khdng sd nhdp nhd be mat gia cdng cdn phu thudc bj Idng dong ciia bgt titan dung djch vao di?n tich vd thiri gian gia cdng: Ra thay dien mdi bang co cau khuay gdm: dgng co ddi tu 0,09 pm den 0,57 fim dien tich gia nen cd tdc dg quay 500 vdng/phiit, canh cdng thay ddi tu cm^ den 64 cm" [9] quat khuay cd dudng kinh 105mm Dung moi Nhiing ket qud nghien ciiu trdn cho thdy rdng dugc cung cap vao viing gia cdng bdng bom viec su dyng bgt kim loai thich hgp trgn vdo A303 cua Trung Qude cd cdng sudt 600 dung djch didn mdi gia cdng tia liia dien lit/gid, dudng kinh vdi phun 08mm Cac Id cdng nghe day hua hen Tuy nhien, can cd thdng sd dugc lya chgn de nghien cdu (Bdng them nhidu nghien riiu, khao sat ve ITnh vyc 1) dua tren ca sd mdt sd nghien cdu tii trudc de hodn thien cdng ngh^ va cd thd dugc Do khdi lugng ciia phdi trudc vd sau gia chap nhga iing dyng thuc tien sdn xudt cdng bang can dien tu AJ 203 (Hang Shinko Trong nghien cdu nay, cac thi nghidm dugc Denshi Co LTD - Japan), khdi lugng Idn nhat tidn hanh vdi su thay ddi ndng dp bdt titan ma can cd the cdn dugc Id 200g, chfnh xac dung djch dien mdi Id dau gia cdng 0.001 g Trj sd nhdm be mat gia cdng (Ra) thdp SKD61 bang phuang phap EDM sir dugc bang may bien dgng kidu dau dung dien cue ddng dd phan cue ngugc tidp xiic SJ-301 (Hang MITUTOYO - JAPAN), Nang suat vd chat lugng ciia qua trinh gia chidu dai chuan Id 5mm, thyc hien lan cdng dugc danh gid thdng qua cdc dgi lugng: tren mdi mau thi nghiem vd ket qud dp nhdm la ndng suat bdc taeh vat lidu, lugng mdn dien gia trj trung binh ciia mdi lan cue vd dg nhdm be mat gia cdng THIET KE THI NGH1$M So thi nghiem dugc trinh bay d Hinh 1, qua trinh phan cue dii gia cdng Id phan cue ngugc (didn cue (-»-), phdi (-)) nhdm khao sat su thay ddi cua MRR, TWR vd R, trudng hgp gia cdng cd bdt trdn dung djch dien mdi Thi nghiem trdn may xung dien CNC- AG40L (Hang Sodick, Inc USA) cua Trung tam thi nghiem Trudng Dgi hge Ky Hinh I Scr Ihl nghi?m Bdng Cdc thong so cong nghe gia cong Thong so Cuong dp ddng dien xung (A) Thai gian xung (^is) Thai gian ngimg xung (^s) Phan cyc Thdi gian gia cong ( ph) Dien dp (V) N6ng dp bdt (g/I) Triso 15 50 85 + 15 150 0.5.10,15.20 Banh" ien Long vd Dtg 135(05): 161 -166 Tgp chi KHOA HOC & CONG NGHE KET QUA VA THAO LUAN Anh hudng den nang suat bdc taeh vat lieu (MRR) Ndng sudt boc taeh vgt lieu (MRR) dugc xac djnh bdi ty sd giiia hidu khdi lugng vat lieu phdi trudc va sau gia cdng vdi thdi gian gia cdng: W,MRR = -^.\Q00mm^ phut pi Trong dd: (1) W, - Khdi lugng mlu trudc gia cdng (g) Wf- Khdi lugng mdu sau gia cdng (g) T - Thdi gian gia cdng cho mdi ldn chay thu (t = 15 phut) p - Khdi lugng ridng ciia vdt lieu mdu (p = 7.81g/cm^) khdng cd bdt Nguydn nhan tdng MRR cd the gidi thich nhu sau: - Khi bdt titan xuat hidn dung dich dien mdi da tgo them rat nhidu cau ndi phdng tia lua dien lam tang mat tia lua didn cung tham gia cdt dan den MRR tang - Bdt titan cd kha ndng dan dien tdt dugc trgn vdo dung dich didn mdi se iam giam ben each didn cua dung dich didn mdi tii ldm giam tieu hao ndng lucmg danh thiing dien mdi Dieu ndy ldm tang nang lugng gia cdng dan den lam tang MRR - Khi ndng bpt tang se dan ddn sd lugng cdc hat bgt xuat hien khe hd phdng tia lira didn tang ldm sd lugng tia liia didn sinh mgt lan phat xung ciing tang len va bdn each dien cua dung djch dien mdi bi giam di nen nang lugng dimg cho danh thung dung dich dien mdi ciing giam theo Khi ndng hot Idn nhat 20g/l thi MRR cao nhat Wffi?n,ax= 1.699mmVphut (tdng 146,75% so vdi khdng cd bgt), nhien ndng dp bdt qud cao cd thd xay hien tugng ngan mgch xuat hien qua trinh gia cdng gay tieu hao nang lugng gia cdng MRR la dgi lugng lien quan tryc tidp ddn thdi gian che tgo san pham, tang MRR se giiip riit ngdn dugc thdi gian gia cdng chi tidt Xdc djnh gid trj MRR cho thi nghidm, mdi thi nghidm Igp ldn Kdt qud (Bdng vd Hinh 2) cho thay vide trdn bdt titan dung djch dien mdi da lam tang MRR so vdi gia cdng Bdng 2, Ket qud ndngsudt boc tdeh vdf lieu TN 10 Wi (S) 31.463 32.671 32.002 31.756 32.651 31.973 31.895 32.906 31.578 31.235 w, (S) 31 365 32.594 31.89 31.658 32.489 31.798 31.71 32.702 31.388 31.027 MRR (mm^hut) 0.837 0.657 0.956 0.837 1.383 1.494 1.579 1.741 622 1.776 MRIZ (mm'/pliiit) N^ngdS b6t(s/l) 0.747 KJiong bot 0.896 1.438 10 1.660 15 1.699 20 v4d»iWWTi(fli Hinh Anh huong cua nong dp bpt din ndng sudt boc tdeh vdl lieu Bdnh Tien Long vd Dig Tap chi KHOA HOC & C N G NGHE Anh birdng din lirgng mon dien cue Lu^g mdn diin cue (TWR) la dai lugng dugc xac djnh bdi ty sd giira hieu khdi lugng vat lieu dien cue trudc va sau gia cdng vdi thdi gian gia cong: T-T, (2) \000mm^ /phut Trong dd: T, - khdi lugng ban dau ciia dien cyc (g) Tf- Khdi lugng dien cyc sau gia cdng (g) t - Thdi gian gia cdng cho mdi ldn chay thu (t = 15phut) PT - Khoi lucmg ridng cua vgt lieu dien cue (pT=8.94g/cm^) Mdn didn cue xdy sudt qud trinh gia cdng ldm dnh hudng ddn dp chinh xac thdng sd hinh hge ciia chi tiet gia cdng TWR tang cdn ldm tang chi phi san xuat phai thay the dien cue bj mdn Kdt qua xdc djnh lugng mdn dien cyc (Bang va Hinh 3) cho thdy: 135(05): 161-166 - Khi dung dich dien mdi khdng cd hot thi TWR la Idn nhat Nguyen nhan la cdc dien tir dugc hinh thdnh qua trinh ion hda chat dien mdi cd dgng lugng va ndng lugng cao se tac dyng len bd mat dien cyc gay xdi mon dien cyc ldn - Khi trgn bdt titan vao dung djch dien mdi da lam TWR gidm Dd la cdc hat bpt di vao viing khe hd phdng tia lira dien cat ngang dudng di chuyen cua cac electron ve phia be mat dign eye Dieu ndy ldm giam ddng lugng ciia cac electron, cdc electron co nang lugng thdp hon tac dung ldn bd mat dien cue lam dien cue it bi xdi mdn hon - TWR dgt gia trj nhd nhat ndng dd bgt la lOg/1, d didu kien kha nang ngdn can sir di chuyen ciia cac electron la Idn nhat nen cdc electron se cd nang lugng nhd nhat tac dung len bd mat dien cyc - Khi cac hgt titan xudt hien vdi ndng dp Idn hon cd thd tao thuan lgi dd mdt sd electron va cac hat bgt ciing tac dyng len be mgt didn cue ldm cho mdn dien cyc xay manh han vi thd TWR tdng nhe ndng ldn hon I Og/I Bang Kit qud lucmg mon dien cue 10 Ti (g) 136.867 138.549 138.549 139.831 137.178 141.197 138.976 138.198 135.893 131.259 T, (g) 136.726 138.411 138.457 139 738 137 095 141.113 138.875 138 098 135.795 131.155 TWR /phit) 1.051 1.029 0.686 0.694 0.619 0.626 0.753 0.746 0.731 0.776 ill TN Nong dO b$t (g/l) 1.040 Khong b$t 0.690 0.623 10 0.749 15 0.753 20 Hinh Anh hu&ng cua ndng dp bpt din luang mon difn circ Banh Tidn Long vd Dig Tap chf KHOA HQC & CONG NGHE Anh hudng den dg nham be mat gia cdng Bang Ket qud dg nhdm be mat gia cong TN Ra(pm) 6.03 4.73 4.38 4.30 4.01 Nong d$ b$t Khong bot 10 15 20 135(05): 161 - 166 ndn trj nhap nhd be mat cung giam theo [II] Do nham Ra nhd nhat ndng bdt titan la 20g/l, ndu tidp tuc tang ndng bdt thi cd thd viec phdng didn bj can trd, hi$n tugng ngdn mach cd thd sd xudt hien nhidu hon lam cho qua trinh gia cdng khdng dn djnh vd nham bd mat gia cdng cd the iai tdng KET LUAN Mpt sd ket luan nhan dugc tir ket qua khdo sdt anh hudng ciia ndng bdt titan den nang sudt vd chat lugng gia cdng thep SKD61 bdng phucmg phdp tia lua dien vdi dien cyc ddng phan cyc ngugc: - Ndng dg bgt titan dung djch dien mdi Id thdng sd cdng nghd cd anh hudng khd ldn den hieu qua gia cdng ciia phuong phap tia Ida dien Nong i(/ b$t Ti (g\) - Ndng suat bdc tdeh vat lidu(MRR) tang Hinh Anh hu&ng cUa nong bot den dp nhdmtdng ndng bdt titan: ndng bgt tang be mgt gia cong '" tir len 20g/l thi WRR tang 146,75% Kdt qua d Bang va Hinh cho thay dg - Khi tang ndng bdt dung djch dien nham be mat gia cdng gidm khd ldn trgn mdi thi mdi ddu lugng mdn di?n cue (TWR) bgt titan vdo dung djch dien mdi (dd thj giam kha mgnh nhung sau dd cd xu hudng cd ddc Idn chuyen td gia cdng khdng tang nhe Lugng mdn didn cue dat gid trj nhd cd bdt sang gia cdng cd bdt dung djch nhat TWRmm~ 0,623mmVphut vdi ndng dp didn mdi) ddng thdi Igi gidm mgt lugng tuong bdtlOg/1, ddi nhd va ddu tidp tuc tang ndng dQ bgt - Dp nhdm be mat gia cdng (Ra) gidm Cd thd giai thich nguyen nhan nhu sau: ndng dp bdt tdng: khdng cd bgt thi Ra - Khi hot xuat hien dung djch didn mdi 6,03pm, ndng dd bgt la 20g/l thi da ldm tang kfch thudc va md rgng vung Ra=4,01pm phdng tia liia dien va tgo didu kien thu§n lgi cho qua trinh van chuyen phoi khdi vung - Cac kdt qud nghien ciiu vdi mdt sd logi hot cdng [4] Cac hat bdt tdn tai khe hd khde nhu: W, Si, Al, da cho thdy rdng ngodi phdng didn lam tia lira didn bi phan chia dnh hudng ti'ch cyc den MRR, TWR, R, thi nhidu tia lua didn cd nang lugng nhd vide trdn bgt vao dung djch dien mdi hon nhidu tham gia gia cdng [6] Didu ndy cdn cd thd cho mgt sd kdt qua khac nhu: da tgo cdc vdt ldm tren be mat gia cdng cd cung td vi bd mat gia cdng tdng, cdu true vd dudng kinh vd chidu sau nhd hon dan ddn hinh dang Idp bd mat cd chat lugng tdt Vi nhdm giam vgy can cd them nhirng nghidn ciru theo - Ndng bgt titan tang thi sd lugng hgt bdt hudng ddi vdi bgt titan tdn tai viing khe hd phdng tia liia dien Ngoai cung cdn nghidn cuu dd lam rd cac cung tdng len, sd lugng cac tia lira dien dugc van de nhu: bdn va su phan bd deu ciia bdt tgo mgt lan phdt xung cung tdng ldn dung djch dien mdi gia cdng lam i^'c "^"8 l^dng cua nidi tia giam xudng 165 Banh Tien Long va Dtg Tgp chi KHOA HOC & CONG NGHE TAI LIEU T H A M K H A O W.S Zhao, Q.G Meng, Z.L Wang, The application of research on powder mixed EDM tn rough machining Joumal of Materials Processing Technology, 129(2002), P 30-33 P Pecas, E Henriques, Influence of silicon powder-mixed dielectric on con-ventional electrical discharge machining International Joumal ofMachine Tools& Manufacture, 43(2003), P 1465-1471 K.H Ho, S.T Newman, Slate of the art electrical discharge machining Inter national Joumal of Machine Tools & Manufacture, 43(2003), P,I287-1300 Fuller, E John, Electrical Discharge Machining ASM Machining Handbook, 16(1996), P 557-564 A Erden, S Bilgin, Role of impurities in electric discharge machining, Proc Of P' intemational machine tool design and research conference,(1980), P.345-350 M.L Jeswani, Effect ofthe addition of graphite powder to kerosene used as the dielectric fluid in electrical discharge machining Wear, 70(1981), P.I33-I39 135(05): 161 - 166 K Kobayashi, T Magara, Y Ozaki, T Yatomi, The present and future developments of electrical discharge machining In proceeding of 2"'' intemational conference on Die and Mould technology, (1992), P 35-47 B.H Yan, S.L Chen, Characteristics ofSKDlI by complex process of electric discharge machining using liquid suspended with aluminum powder, J Jpn Inst Light Met., 58(2004), P 10671072 P Pecas, c Henriques, Electrical discharge machining using simple and powder-mixed dielectric: The effect of the electrode area in the surface roughness and topography, Joumal of materials processing technology 200(2008), P.250-258 10 Y.S Wong, UC Lim, Rahuman, W.M Tee, Near mirror-finish phenomenon in EDM using powder-mixed dielectric Joumal ofMaterials Processing Technology, 79(1998), P.30-40 11.P Pecas, E Henriques, Influence of silicon powder-mixed dielectric on con-ventional electrical discharge machining, Intemational Journal of Machine Tools& Manufacture, 43(2003), P 1465-1471 SUMMARY EFFECT OF MIXING TITANIUM POWDER CONCENTRATIONS INTO D I E L E C T R I C FLUID ON T H E M A C H I N I N G E F F I C I E N C Y AND P E R F O R M A N C E IN DIE - SINKING E L E C T R I C A L D I S C H A R G E MACHINING O F SKD61 S T E E L Banh Tien Long', Ngo Cuong^ Nguyen Huu Phan^', Tran Quang Cong"* 'Hanoi University of Science and Tecltnology, Hanoi Vietnam 'College of Economics and Technology - TNU, ^The college ofmachanics and melallury - Thai Nguyen Electrical discharge machining (EDM) has found widespread applications in tool and mold industries, and aerospace industries Therefore, enhancement ofthe quality ofthe EDM process has become a major research concern In this paper, the effect of various titanium powder concenUations on the Material Removal Rate (MRR), tool wear rate (TWR), surface roughness (SR) in following powder - mixed electrical discharge machining (PMEDM) have been caried out The hot work steel SKD6I and electrode made from copper with reverse polarity were used in • experimental study The results showed that titanium powder mixed into the dielectric fluid of EDM can enhance MRR without increasing TWR, and improve the SR Keys word; EDM PMEDM, MRR TWR powder mixed Ngdy nhdn bdi:26/lO/20I4 Ngdy phdn bien: 12/11/2014; Ngdy duyet ddng: 31/5/2015 Phdn bien khoa hoc: PGS TS Nguyin Qude Tudn - Dgi hpc Thdi Nguyen Tel 0983 783844: Email: Phanklcn@gmaiLci 166 ... phdi trudc va sau gia cdng vdi thdi gian gia cdng: W,MRR = -^.\Q00mm^ phut pi Trong dd: (1) W, - Khdi lugng mlu trudc gia cdng (g) Wf- Khdi lugng mdu sau gia cdng (g) T - Thdi gian gia cdng cho mdi... cue trudc va sau gia cdng vdi thdi gian gia cong: T-T, (2) \000mm^ /phut Trong dd: T, - khdi lugng ban dau ciia dien cyc (g) Tf- Khdi lugng dien cyc sau gia cdng (g) t - Thdi gian gia cdng cho mdi... thich nhu sau: - Khi bdt titan xuat hidn dung dich dien mdi da tgo them rat nhidu cau ndi phdng tia lua dien lam tang mat tia lua didn cung tham gia cdt dan den MRR tang - Bdt titan cd kha ndng dan