Thiết kế, chế tạo thiết bị đo lực cắt quá trình tiện

NGHIEN COfU - TRAO D | ^/ THiiT Kg, C H i TAO THIET Bj OO LU'C CAT QUA TRJNH TIEN DESIGN AND MANUFACTURE INSTRUMENTATION MEASUREMENT CUTTING FORCE OF TURNING Le Due Bao, Bui Long Vinh Trudng Dai hgc Bach Khoa Ha Ndi TOM TAT Bdi bdo trinh bay tinh todn, thiit ke vd chi tgo thiit bi luc cdt qud trinh tiin theo phuang X, Y.Z Tin hiiu luc cdt thu duac tir luc ki se dugc truyin tai mdy tinh di phdn tich, xir ly phuc vu cho muc dich dieu khiin Luc ke dugc thiet ke vd che tgo dua tren nguyen tdc luc bdng cdm bien tem bien dgng Ciing bdi bdo ndy cdc kit qud thuc nghiim luc cdt vdi nhieu che cdt khdc se duac trinh bay Gid tri lire cdt dugc gdn dung vdi gid tri tinh todn bdng ly thuyet, dieu ndy cho thdy thiet bi luc cat hogt dgng on dinh, chinh xdc TiJr khda: Thiet bi luc, luc ke, che tgo luc ke ABSTRACT This pcq}er presents the calculation, design and manufacture instrumentation measurement _ cutting force for tum by direction X, Y.Z Signals obtained from dynamometer will be transmitted to a computer for analysis and processing service for control purposes Dynamometer is designed and manufactured based on the principle of force measurement by strain gauges Also in this paper the experimental results measured cutting force with many different cuttingcondition will be presented Values measured cpproximate with value calculated by theory, this shows dynamometer stable operation, accurate Keywords: Measurement cutting force, turning machine ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, Sd 12 nam 2015 www cokhivietn am '^ NGHIEN CUTU-TRAO Ddi DAT VAN DE Cac nghien ciiu va ngoai nude da chi rang, lire cdt phu thudc vao vat lieu phdi, dao, che cdt Do lire cdt qua trinh gia cdng se cung cap mdt thdng sd giiip phat hien luai cat hi mdn hay gay hoac phat hien va dap Nhu vay, cd the thdy luc cdt la mgt nhung thdng sd quan trgng qua trinh gia cdng cdn dugc xac dinh chinh xac De nghien ciiu cac qua trinh gia cdng cdt ggt hien dai, can phai cd cac thiet bi lire cd chat lugng cao Nhung hien nay, chiing ta cdn thieu cac bg luc dimg cho nghien ciiu va dao tao Viec nhap ngoai cdc bd dung cu ddi hdi chi phi rdt cao khdng phia hgp vdi dieu kien kinh te d nude ta Do dd, vdn de nghien ciiu thiet ke che tao thiet bi luc cat vdi chi phi giam dap ting dugc cho nhu can nghien ciiu va dao tao dieu kien thuc te a nuac ta la mgt vdn de cdp thidt Vai muc dich do, chiing tdi da tien hanh nghien ciiu vd che tao cacthi6t bi lire cho qua trinh gia cdng cdt ggt Buac dau da che tao cdng luc kg phan (theo phuang X, Y, Z) dua tren nguyen tac luc bdng cam bi^n tem biSn dang Ly'C KE BA THANH PHAN Trong qua trinh tien dao chuyen ddng vao cat phdi se sinh luc cdt F [1] Luc F dugc phdn tich thanh phan: F^ - Luc chieu true, F^ - Luc hudng kinh, Fc - Luc cdt chinh hay luc ti6p tuy^n nhu hinh 1: Hinh Phdn tich luc cdt tiin D6 dugc cdc phdn lire tren thi lire ke dugc thiSt k8 gdm cac phdn: Cac phdn tii dan hdi, tren cac phdn tii dan hdi cd dan cac tem bien dang (strain gauges), cdc tem bien dang dugc ndi vdi mach cau Wheatstone (Wheatstone Bridge), mach khuyech dai, mach chuydn ddi tin hieu tuang tu sang tin hieu sd (ADC: Analog to Digital Converter) HPtaiS^^^ IT-X ^ ,^ [-1 H B u t a * ^ { JM '^'-^ PC i J IT* " Hinh 2.He thdng luc cdt tren mdy tien CNC Trong qud trinh gia cdng luc cdt dugc sinh gdy bien dang cac phdn tu dan hoi va lam cac tem bien dang cung hi bien dang theo dan den su thay ddi dien trd cua nd Chenh lech trd khang lam cho mach cau hi mdt cdn bdng tao tin hieu dien dp mV Mach ADC se chuyen ddi tin hieu di?n ap dd dugc khuech dai tin hieu sd Nhd dd tin hidu dugc ma hda dua vao may tinh Vi?c thu nhdn, xii ly, hidn thi kit qua luc cat dugc thuc hiSn tren may tinh thdng qua phdn m6m XKM2000 De luc cdt theo phuang dieu kien tinh va ddng thi sii dimg theo phuang phap vdng dan hdi [3] Kich thudc cua vong dan hdi dugc tinh toan dua vao ldn ciia luc va chinh xac ciia phep Phdn tich vdng dan hdi cd ban kinh r, chiSu day t, chidu rdng b chiu luc hudmg kinh F^ va luc tidp tuydn F tac dung (hmh 3a) Hinh 3: Qud trinh bien dgng cua vdng ddn hdi ISSN 0866 - 7056 TAP CHi CO KHf VIET NAM, Sd 12 ndm 2015 www.cokhivietnam.vn NGHIEN CUfU - TRAO D O I Theo ly thuydt dan hdi vdi vdng manh, chi cd lyc Ft tdc dung (hhih 3b) thi bidn dang a be mat vd ngodi ciia vdng dan hdi tai diem A la: quan trgng cua luc ke la cung viing vd dg nhay De cd the dat dugc dd nhgy cao thi vong tam canh cdn phdi dugc thiet ke va ddt a vi tri bi bien dang nhieu nhdt bdi cdc phdn luc Cam bien bien dang dugc dan tren vong tam canh noi ma nd se bi keo hoac nen lan nhdt Bdn vdng tam canh dugc bd tri de luc theo E.h.t^ ^ ^ phugng ddc l|ip vdi Vi tri ciia vdng tdm canh tren hai tdm tren vd dudi dugc thd hiSn nhu Vdi E^: la biln dang tai diim A; F^ tren hinh 4: Id luc hudng kinh (N); r la bdn kinh vdng trdn (mm); E la md dun dan hdi(N/mm); b la chidu rgng vang dan h6i(mm); t la chieu day vdng dan hdi (mm) Trong tai didm B vi tri nghieng mgt gdc 39.6 so vdi truetiidngdiing, bidn d^g bang Khi chi cd luc F^ tdc dung (hinh 3c) bien d^g tai diem A bang bien dang tai diem B la: , 2,18J^,.r Hinh 4: Sa dd bd tri cdc phdn tir ddn hdi vd tem bien dgng luc ki (4) Vdi: 8g la bien dang tai diem B; Fc la luc tiep tuyen (N) Neu bien dang tai diem A va B pham vi gidi ban dan hdi ciia vdt lieu thi phuang trinh (2) va (3) sg tuydn tinh vdi luc va \d the vdng dan hdi dap iing dugc yeu cdu mong mudn ve tuyen tinh Gia tri ciing viing cua vdng hinh trdn mong theo phuang hudng kfnh vd tiSp tuyen dugc tinh nhu sau: Tin hieu luc F, dugc tao cac phdn tu dan hdi cac vi tri A,B,C va D hi bien dang ldm cho tem bidn dang 3,4,7,8,11,12,15 vd 16 hi bien dang Trong dd cac tem bien dang 3,7,11 va 15 chiu keo va 4,8,12,16 chiu nen Tin hieu luc F^ dugc tao cac phdn tu dan hdi d cac vi tri A,C bi bidn dang ldm cho cac tem bien dang 1,2,5 va hi bien dang Trong F Ehi" do, cac tem bien dang 1,5 chiu keo va 2,6 chiu nen Tin hieu luc F^ dugc tao cac phan tu ddn hdi d cac vi tri B, D hi bien dang lam cho K,=^^^i6) tem bien dang 9,10,13 va 14 hi bien dmig Trong ' S, 3,6./-' dd, cac tem bien dang 10, 14 chiu keo vd 9, 13 Vdng tdm canh dugc dung lam phan tu chiu nen dan hdi cua luc kd tien \d nhung uu diem cua nd so vdi vdng trdn De dam bao dugc tinh lien tuc KET QUA THlTC NGHIEM tuyen tinh va su lap lai do, cdc vdng tdm canh dugc che tao tu vdt lieu ddng nhdt Ket qua thyc nghiem dugc thuc hien Vdng tdm canh phai dam bdo tinh ddi xiing, chdt tren may tien CNC cua hang EMCO vcri bd dieu lugng bd mat vd chinh xac cao Hai chi tieu khien Sinumerik ddy la may tien bdng nghieng,'^ ISSN 0866 - 7056 TAP CHi CO KHi VlfiT NAM, Sd 12 ndm 2015 www.cokhivietnaiii.vn NGHIEN C U T U - T R A O D O I dilu khiln true Chiic nang dieu khien CNC dugc thuc hien tten may tinh, lap trinh ttong mdi trudng Windows Luc k l dugc ldp tten tich dao va chi tilt gia cdng dugc gd tten mdm cap didn tren hinh F«N -i — -.- ,, rffft- r~l • 2* L(mni) M M IN 1» i« in IM Hinh 5: Md hinh thuc nghiim Anh hudng cua lugng tien dao den luc cdt dugc thuc hidn d che cat khdc Bang thi hien kit qua thu dugc gia tri luc cdt d che dg cat dugc thilt l|ip nhu sau: Chieu sdu cat t =2 mm, lugng chay dao S^0,1 -^ 0,8 mm/v, tdc quay true chinh n = 940 v/ph, phdi cd dudng kinh D=35mm Dd thi anh hudng dugc bieu dien ttSn hinh ã Wi\m\ M ô L(mm) W n IM 12* 1ô 1ô ô ã IM Hinh Dd thi dnh hudng cua lugng tien dao den luc cdt vdi t = 2mm S=0,1 -^ 0.8 mm/v, n = 940 v/ph, D=35mm Bang la kit qua gia tri lyc cat thu dugc d chi cdt dugc thilt lap chilu sdu cdt t=2mm, Bdng 1: Gid tr} cdc luc thdnh phdn vd luc cdt ti$n vdi che dQt = 2mm, S=0,1 -^ 0,8 mm/v, n = 940 D-35mm, S-0,3mm/v, Vc=7,l-192,4m/ph, v/ph, D=35mm n=65-^1750v/ph Dd thi anh hudng dugc bilu dien tten hinh F ^ F.(N) Fp(N) S (mm/v) Bdng 2: Gid tri cdc luc thdnh phdn vd luc cat 250 155 238 0,1 tiin vdi chi t=2mm, D=35mm, S=0.3mm/v 473 338 0,2 548 Vc=7,1^192,4m/ph n=65^1750v/ph 541 686 892 1037 1086 1482 454 576 630 683 670 740 339 422 505 569 584 828 0,3 0,4 0,5 0,6 0,7 0,8 Bang la ket qua gia tri luc cdt thu dugc d ch6 dd cat dugc thiet lap chieu sdu cat ^ m m , D=35mm, S=0,3mm/v, V^=7,l-l92,4m/ph, n=65-1750v/ph Dd thi dnh hudng dugc bilu F(N) 868 881 815 794 819 813 800 797 ISSN 0866 - 7056 TAP CHi CO KHi VlfiT NAM, Sd 12 nam 2015 www.cokhivietnam.vn F ^ 523 538 533 513 587 599 572 556 F,(N) V^ (m/ph) 433 428 417 403 464 458 432 426 17,6 34,1 42,9 72,6 103,4 142,9 182,4 7,1 NGHIEN CUlU - TRAO Ddi Bang 1^ kfit qua gia tri luc cat thu duac a chd dp cit ducrc thidt lap chiSu sSu c5t t=0,5-f^2,5mm, D=35min, n=940v/ph, S=40mm/v, Vc=118,lm/ph Da thi anh huong dugc bieu diin tren hinh yoi '^\ ttm F.(N _^r Bdng 3: Gid trj cdc luc thdnh phdn vd lifC cdt lien v&i chi dQ t=0,5^2.5mm, D=35mm, n=940v/ ph, S=40mm/v, V~U8.1m/ph F(N) i - F ^ 203 416 606 859 354 622 876 1147 1451 Fp(N) t(mm) 288 421 511 680 840 0,5 1,5 2,5 1087 L(mn.) '^X Hinh 8: Do thi dnh hudng cita lugng tien dao den luc cdt vdi t=0,5^2,5mm D=35mm, n=940v/ph, S=40mm/v Vc=H8,lm/ph KET LUAN R:(F| mrnm L|mnn} Chi phi cua he thong lyc cdt dugc nghidn euu thilt ke che t^o cdng cd gid Ihanh re ban rat nhieu so vdi lyc kd cila cdc hdng Tuy nhien, vdi ket qua thyc nghi?m dat dugc vd so sanh vdi gia tri tinh toan ly thuyet nhdn thdy, giai lyc dugc hoan toan chinh xdc, hgp !>• Dd cung vung cua he thdng khd cao va quanttgngla phu hgp vdi myc dich nghien ciiu va dao tao.