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NGHIEN CUTU-TRAO DOI y P H l / a N G PHAP DO NHIET BANG BLTC XA KHONG TIEP XUC KHI GIA CONG TOC DO CAO MEASUREMENT TEMPERATURE BY NONCONTACT RADIOMETRIC METHOD WHEN HIGH SPEED MACHINNING Nguyen Tien Nga Trudng Cao dSng Ky thuat Cdng nghiep (Bac Giang) TOM TAT Nhiet cat vd nhiet phdn bo doc theo phdn tiep xiic giua dung cu cat vdi chi tiet gia cong qud trinh cat Id nhan td co bdn nghien ciru qud trinh gia cong kim loai bdi vi no dnh hudng den chat luong be mat, tuoi ben cua dung cu, chinh xdc gia cong, trgng thdi kim loai vd tdc bdc tdch phoi Da cd mot so phuong phdp dua each nhiet qud trinh cat nhu phuong phdp P^ thuat cap nhiet dien, dnh nhiet hdng ngoai vd cdc phuong phdp thuc nghiem cat kim loai Mdi phuong phdp cd nhimg uu diem vd nhirng han che rieng Trong bdi bdo tdc gid dua phucmg phdp nhiet cd su dung mot he nhiet dong phat sinh qud trinh cat bao gdm mot day cdc cam bien quang nhiet HgTeCd, cd the duoc cdc tin hieu thoi gian phat nhiet sap si 250 nano giay vd cung cdp du chinh xdc de thu duoc nhiet sudt qud trinh gia cdng Cdc thuc nghiem viing nhiet phat sinh qud trinh gia cdng hop kim nhdm cd che cat la chieu cat 0,5 mm, gdc cat a = 5,5°, van tdc cat 30 m/s vd su dung mdnh dao hop kim cd viing mon vd dao sac Tir khoa: Phucmg phdp nhiet cat; Do nhiet khdng tiep xiic; Do nhiet bdng hdng ngoai ABSTRACT The cutting temperature and temperature distribution along the rake face of cutting tool and work piece is an essential factor in study of machining processes due to its effect on surface quality, tool life, tolerances, metallurgical behavior and chip-removing rate Several methods have been introduced to measure temperature during machining, such as the thermocouple technique, infrared camera and metallurgical methods Each of these methods has some advantages and limitations In this article, a dynamic temperaturedynamic temperature system using a linear array ofphotoconductive HgTeCd detectors has been used to record the signal real time of approximately 250 ns and provides sufficent resolution to capture transient temperature for during high speed machining (HSM) The experimental measures of the temperate fiels generated during machining Aluminum Alloy for cutting with a 0,5 mm depth of cut and 5,5" rake angle at 30m/s velocity using tools has a wear -land and sharp tool Keywords: Temperature measurement; Non-Contact temperature measurement TAP CHI CO KHI VIET NAM, Sd nam 2014 www.cokhivietnam.vn Temperature Measurement, infrared NGHIEN CUfU - TRAO OOl DAT VAN DE Thyc nghiem da ehiing td rang, qua trinh cat ggt kim loai gan nhu tat ca cac cdng can thiet qua trinh eat ddu bidn nhiet Phan Idn nhiet da dugc vao phoi cit nhung mpt phan nhiet khdng nhd dupe truyen sang dung eu cat va ehi tiet gia edng Viec xac dinh nhiet dp ciia qua trinh gia cdng la het sue quan trpng dac biet la bdi eanh hien ma nganh Cdng nghe ehe tao may cdng cu, vat lieu dung cu cat rat phat trien va da dat dugc nhieu tuu, thi yeu cau ciia nganh gia cdng eat ggt la lam de tang tde dp eat, nang cao nang suat gia cdng gdp phan giam chi phi gia cdng la het siic biic thiet Do dd, gia cdng cao tde, dat cho chiing ta la lam the nao de dinh dugc nhiet dung eu cat, tren ehi tiet gia cdng Day la mot van de kho khan nhung rat quan trgng thiet ke, ehe tao va sii dung dung cu, bdi vi nhiet va sy phan bd nhiet dung cu ed quan he mat thiet vdi qua trinh suy giam ciing cua vat lieu dung eu cat d vimg ludi cat ciing nhu ca ehe mdn va tde dp mdn xay d dd, lam thay ddi eac thdng sd hinh hoc cua dung cu, giam tudi ben ciing nhu kha nang lam vice cua dung cu, mdn anh hudng tryc tidp ddn chat lugng va dp chinh xac ciia be mat gia cdng Ngoai ra, nhiet truyen sang chi tiet gia cdng lam thay ddi tinh chat ca - ly Idp be mat, gay ling suSt du cd the gay sai sd gia edng ciing nhu pha huy ehi tiet vi phan rieng phan cimg vdi eac dieu kien bien cu the Co sd ciia phuong phap la lam rdi rac hoa cac mien lien tuc phiic tap cua bai toan Cac mien lien tuc dugc chia nhieu mien (phan tir) Cae mien dugc lien ket vdi tai cac diem mit Tren mien nay, dang bi6n phan tuong duong vdi bai toan dugc giai xap xi dya tren cae ham xap xi tren timg phan tir, thoa man dieu kien tren bien eiing vdi su can bang va hen tuc giiia eae phan tir Tuy nhien, phuong phap da sir dung eae phep toan gia djnh, thuc te khdng phai hoan toan nhu vay va cae kdt qua duge tinh toan cd sir dung phep tinh xap xi cho nen ket qua cd phan sai lech Ngoai ra, ed rat nhieu phuang phap khae xac dinh nhiet cat nhu xac dinh nhiet eat bang phuang trinh thuc nghiem thdng qua viee xac dinh anh hudng eua mot sd yeu td nhu vat lieu gia edng, vat lieu lam dao, tdc dp eat, chieu day, rong ciia lap eat, cae thdng sd hinh hgc eiia dao, ta cd the thiet lap dugc phuong trinh kinh nghiem tinh toan nhiet cat NOI DUNG NGHIEN ClTU Qua cac nghien eiiu va tir thye te cat ggt ta thay rang nhiet cat cd anh hudng rat Idn den qua trinh cat, vay, can phai xac dinh dugc Idn ciia chiing nhung trudng hop cat gpt cu the Tuy thude vao muc dich nghien ciiu ma ta cd the xac dinh nhiet eat tren dao, tren chi tiet, tren phoi hoac d mdi trudng chung quanh Sy phan tieh ly thuyet ve sy thu nhan nhiet ciia qua trinh cat cho kha nang danh gia duge anh hugng eua cac thdng so CO ban cd lien quan den qua trinh cat den sy xuat hien va su dan nhiet eat, nhien, viee xac dinh su thu nhan nhiet bang tinh toan la r4t khd va khdng chinh xac nen chi thudng dupe ap dung viec dac nhiet dp tryc tidp khd khan hoac khdng the tien hanh dugc Cd thd noi rang, cho den nay, ly thuyet trao ddi nhiet chua thd md ta chinh xae trudng nhiet cat dd dinh lugng dugc nhiet dp tai cac dikm cu thd tren dung eu cat Tuy vay, viec nghien eiiu ly thuydt rat cd y nghia dieu kien true tidp gap kho khan, khdng chinh xae hoac khdng thk tidn hanh dugc De nghien ciiu ye trudng nhiet xuat hien dung cu cat, gan day ngudi ta hay su dyng phucmg phap phan Ngay nay, vdi sy phat trien ciia cac nganh tu hiiu han dd xac dinh trudng nhiet dp Phuang khoa hpc, ky thuat nhiet ndi chung va nhiet phap phan tu h&u han la phuang phap sd dimg de cat ndi rieng cang hoan hao Do vay, viec giai cac bai toan dugc md ta bdi cac phuang trinh xac dinh nhiet cat bang caeh la phd biSn Hien nay, ^ TAP CHI CO KHI VIET NAM, Sd nam 2014 www.cokhivietnam.vn NGHIEN CUfU-TRAO D C I phuang phap tdt nhat de nhiet ly cat qua De cac phep dugc thyc hien, day cac trinh gia cdng true giao la phuang phap biic bd dd dupe tap trung tren be mat dudi cua mau, xa khdng tiep xiic Day la phuang phap cung cap tren dudng thSng vudng gdc vdi hudng eat va each trudng nhiet dp thuan tien nhimg be mat nam khoang giiia cac vat mau Hinh la he quang phdi ma khdng can thiep vdi qua trinh cat Cae hgc dugc su dyng nhiet gia cdng cao tien bd gan day cac thiet bi dd hdng ngoai tdc He thdng bao gom: Guong 1dm duge phu mot eho phep nhiet dp tai mpi thdi diem, ket qua Idp nhdm va hai guong phang dd cd mpt ca hai khdng gian va thdi gian cua ITnh vuc guong phang dupe phu Idp vang Lap phii de tang dpng nhiet hgc Cd rat nhieu he thdng khac eudng cac phan xa birc xa hong ngoai Sy phdng da dugc thiet ke va su dung cac nd dai cua he thdng quang hpc cd the dupe thay doi luc de nhiet dp xung quanh vimg ludi cat (miii nhung da dugc chgn mpt gia tri Chii y cSn chinh dao) Vi du nhu phuang phap cap nhiet dien; Phim he thdng quan hpc cho luon duge tap tnmg nhay eam nhiet hoac la cac thiet bi quet nhiet Tuy tren bg mat dudi cua phdi va diing vi tri dau cua nhien, he thdng nhiet dugc trinh bay sau day cd mpt sd Igi the so vdi cac he thdng khac Bdi vi rat khd khan dd dua mpt each Thii nhat, he thdng khdng thay ddi dang ke mien chinh xae mdi quan he giai tieh giiia diSn ap va bien dang, thii la he thdng khdng thay ddi dang nhiet cho he thdng nhu the nay, vi v4y, ke mien nhiet, thii la he thdng dugc day du hau hdt cac nha nghien eiiu dS thir nghiem m6t mien nhiet va thir la he thdng cd kha nang dap thi nghiem chuan cung cap mgt mdi quan he tnrc ling thdi gian nhanh ti8p giua nhiet tren be mat cua phdi va dien ap eua he thdng nhiet dd gia cdng cao toe Trong he thdng ghi nhiet dp gia cdng Rd rang cac dieu kien ciia mot thi nghiem thyc tS cao tdc sir dung mpt day cac cam bien quang dan cd the dugc thiet lap ma thuc hien mpt hieu HgCdTe, day bao gom 15 thiet bi kich thudc chinh Trong thi nghiem tren, mdi mpt bd dd dugc 80 X 80 |im vdi khoang each tir tam cac cam bien hieu chinh can than bang each su dung phuong la lOO^m va cd tdng chieu dai dat cam bien la phap dan gian cua cac nha nghien cim trudc day 1,48 mm Day cac cam bien dat d dang sau eira [2, 3, 4, 7] Hinh chi dang dudng cong nhiet shaphire mot binh Dewar chua Nita Idng chuan gia cong cao tdc hgp kim nhdm Dieu cho phep cac bd dd dupe lam lanh tdi 77 K de giam thieu nhieu dien va tdi da hoa sy nhay He thdng nhiet cd tin hieu khoang thdi gian xap xi 250 ns va eung cap dp phan giai du de bat tin hieu nhiet ehuyen tiep cho tdc dp cat cao Hinh 2: Dudng cong nhiet chudn gia cong hop kim nhdm 6061-T6 Hinh I: He thdng quang hoc nhiet Da thire thii dugc su dyng nhu chiic nang chuydn ddi dien ap sang nhiSt dp Bdi vi cae thidt bi dd hdng ngoai khdng xae dinh dugc nhiet dp thuc nhimg sy khac nhiet dp, nd can thidt phai kd den nhidt dd phdng qua trinh thi nghiem TAP CHi CO KHI VIET NAM, Sd nam 2014 www.cokhivietnam.vn NGHIEN CaU-TRAODOl Chu y rang, nham b^ mat cua hgp kim nhdm cd thd thay doi dang kd sudt qua trinh bien dang Anh hudng ciia nham be mat len cac chi sd he thdng da dugc trinh bay bdi cae nha nghien ciiu [4, 6] Mason [5] da chi rang sy phu thudc cua cae bd dd hdng ngoai nhiet dung cu cat khdng phai la hinh anh va nhiet dp Idn nhit xudt hien tren bg mat tidp xiic dung eu/phoi Hon ntia true y la true xac dinh vi tri ciia bd dd thi d mpt ty le khac vdi true x, vi tri dgc theo dudng din cat * Do nhiet cat qua trinh gia cdng: Hinh dai dien cho mot linh vyc nhiet qua trinh cat dugc thuc hien vdi tdc eat v ^ 30 m/s, chieu sau cat t = 0,5 mm, gdc cat a ^ 5,5", su dung manh hgp kim vonfram H13A, day hdng ngoai dugc tap trung ben trdn miii dao dd nhan duac nhiet dp Idn nhat, thudng xuat hien tren mat Hinh 4: Nhiet phdn bd vdi dung cu cdl cd goc cdt nghieng mpt khoang tir miii dao Vi tri eiia miii a = 5.5° vd chieu sdu cat t = 0,5 mm dao thudng duge udc lugng la x =^ 0,50 mm, y ^ 0,36 mm Nhiet dp Idn nhat nhan dugc cac Gia tri nhiet dp cat Idn nhat eho tdt ca 12 thi nghiem la 23S°C va dugc ghi lai d vi tri x = lan thi nghiem dupe cho bang dudi day, nd 0,38 mm, y = 1,25 mm cho thay rang su khac giiia nhiet dp Idn nhat sir dung manh dao cat HI A va D2 khdng Idn Hinh dua mpt mien nhiet dp qua trinh va nhd hon 10% gia trj nhiet Idn nhdt Han c5t vdi cat v = 30 m/s, chieu sau cat la t = 0,5 nira, gia tri ciia nhiet dp cat Idn nhat tang Ign vdi mm va gdc cat a ^ -5,5", sii dung manh hgp sy giam gdc cat Tuy nhien, cd mpt budc nhay Idn kim von&am H13A Vi tri cua mui dao dugc udc vg gia tri Idn nhat ciia nhiet thay ddi gia trj lugng X ^ 0,5 mm, y = -0,56 mm Nhiet dp Idn gdc cat a tir 0'' den - 5,5" so vdi thay ddi gdc nhat nhan dugc thi nghiem la 336"C va cdt a tir 5,5" tdi 0° Ngoai ra, cd su tang nhiet dp d vi tri X - 0,69 mm, y ^ 0,94 mm Dir lieu thi nghiem da khdng thay ddi khdng ke mau nao deu cat Idn nhat cimg vdi tang chieu sau cat cd nhiet tap trung d nhirng kgt qua tren Dudng Nhiet do duoc khi thay ddi diAng cu cong nhiet dp chuan (H2) da dugc sii dung de xac dinh tuong quan dien ap tir eac bd dd HgCdTe cdt gdc cdt, chieu sdu cdt va nhiet dd cat Goc cit cua dao Dao gan manh hcrp kim H13A Dao lam bang vat lieu D2 Chieu sau cat t (nun) Chieu sau cat t (mm) 0,25 0,5 0,25 0,5 5.5" 201" 238" 223" 258" 0" 222" 271" 242" 275" -5,5" 282" 336" 296" 321" * Do nhiet dp viing mdn Hinh 3: Nhiet phdn bd vdi dung cu cdt cd gdc cdt Nhiet tap trung nhan dugc tir nghien cihi chi rang dp Idn cua nhiet phat sinh (J = 5,5" vd chieu sdu cat t = 0.5 mm phdi vimg lan can bg mat gia cdng lan Chii y rdng tit ca cac sd ehi cudi thi nhd hem nhidu so vdi nhiet cdt Idn nhat Mpt "^ TAP CHI CO KHI VIET NAM, Sd nam 2014 www.cokhivietnam.vn NGHIEN CUfU-TRAO DOI each lam tang Idn cua nhiet phdi gia cdng la dua vao dao cdt mot lugng mdn (Hmh 6), no se lam giam gdc cat a va lam phat sinh ma sat, digu tac ddng viirig phat sinh nhiet ttong phdi va dan mot ung suat du trgn bg mat san pham dung dao cd viing mdn va dao sac, hildng cat til trai sang phai Cac biic anh rd rang chi co cac Idp bien ciing tren b^ mat cua san pham sil dung manh dao cd viing mdn Thuc hien lam thi nghiem nghien ciiu anh hudng cua vimg mdn len sy phat sinh nhiet tren be mat phdi gia cdng Hinh dua mien tap trung nhiet img vdi che sau (1): Chieu sau cat t ^ 0,5 mm, gdc cat a = 5,5°, v ^ 30 m/s va sir dung manh dao cae bit vontram co viing mdn Nhiet dp Ion nhat thu dupe tren be mat gia cdng la 106"C Hinh 8: Be mat gia cong sit dung dao co viing mdn Hinh Nhiet phdn bo sudt qud trinh gia cdng cao tdc vdi che cdt (I) Hinh 7, thg hien mien tap trung nhiet ling Hmh 9: Be mat gia cong sii dung dao Co viing mon vdi chg cat (11): chigu sau cdt t = 0,5 mm, gdc cat a ^ 5,5", V = 30 m/s va sir dung manh cac bit vonfram sac Ket qua thay ring vimg nhiet khong KET LUAN phat trien nhigu ben dudi miii dao va dp Idn eiia Nhiet dp phan bo duoc dua td nghita viing phat nhiet tren phdi khdng nhigu ciJu cua Vernaza Pena et al [19] va cac kft qua dUdc cua thi nghiem tren thay rang nhiet tren be mat gia cong lan cuoi nho hon nhieu so vdi nhiet dp 16n nhat Mpt each de lam tang nhiet dp truyfa sang phpi la s\i dung dao co vung mon Dao co vung mon (hinh 6) la dang chung ciia diong cat bi mpn, no lam cho gpc cat bi giam va lam tang ma sat qua trinh gia cong lan cuoi Dieu nay, lam tang vimg phat sinh nhiet phoi va do lam phat sinh ijfng suat tren be mat san pham Do dd anh hudng cua viing mon da dupe tim Nghien cUu linh vUc nhiet phat sinh Hinh Nhiet phdn bo sudt qud trinh gia qua trinh gia cong cao toe vdi mot dung cu cdng cao tdc vdi che cdt (II) cat CO mpt vung mon chi rang viing mon la mpt Hinh 8, the hien be mat san pham si£ ngudn nhiet dang ke TAP CHI CO KHI VIET NAM, So nam 2014 www.cokhivietnam.vn NGHIEN CUfU-TRAO OOl Nhiet cdt dugc qua trinh gia cdng cao tdc chi rang nhiet cat tang giam gdc cdt va tang chieu sau cdt Vdi trudng hgp dao cd vung mdn la 0,75nim eat vdi chidu sau cdt t ^ 0,5 mm va gdc cdt la 5,5", van tdc cdt 30 m/s, sir dung manh eae bit HlSAthi nhiet cdt phdi la 106"C, nd bang khoang % nhiet Idn nhdt phat sinh qiia trinh edt • Ngay nhan bai: 12/4/2014 Ngay phan bien: 20/5/2014 Tai li^u tham kh^o: [1] Banh Tign Long, TrSn Thg Luc, Trdn Sy Tuy (2001), Nguyen lygia cong vdt lieu, NXB Khoa hoc Ky thuat Ha Noi [2] Duffy J, Campbell JD, Hawley RH (1971) On the use of torsional spUt-hopkinson bar to study rate effects in 1100-0 aluminum J Appl Mech 93:83-91 [3] Duffy J, Chi YC (1992) On the measurement of local strainand temperature during the formation of adiabatic shear bands Mater Sci EngA157:195-210 [4] Hartley KA, Duffy J, Hawley RH (1987) Measurement of the temperature profile during shear band formation in steels deforming at high strain rates J Mech Phys Solids 35(3): 283-301 [5] Mason JJ, Rosakis AJ, Ravichandran G (1993) Use of high- speed infrared detectors for dynamic deformation and failure Experimental techniques in the dynamics of deformable solids ASME-AMD 165:11-24 [6] Mason JJ, Rosakis AJ, Ravichandran G (1994) On the strain and strain rate dependence of the fraction of plastic work converted to heat: an experimental study using high speed infrared detectors and the kolsky bar Mech Mater 17: 135-145 [7] Zehnder AT, Rosakis AJ (1991) On the temperamre distribution at the vicinity of dynamic propagating cracks in 4340 steel J Mech Phys Solids 39(3):385^15 TAP CHI CO KHI VIET NAM, Sd nam 2014 www.cokhivietnam.vn ... tuu, thi yeu cau ciia nganh gia cdng eat ggt la lam de tang tde dp eat, nang cao nang suat gia cdng gdp phan giam chi phi gia cdng la het siic biic thiet Do dd, gia cdng cao tde, dat cho chiing ta... thdi gian nhanh ti8p giua nhiet tren be mat cua phdi va dien ap eua he thdng nhiet dd gia cdng cao toe Trong he thdng ghi nhiet dp gia cdng Rd rang cac dieu kien ciia mot thi nghiem thyc tS cao. .. ngudn nhiet dang ke TAP CHI CO KHI VIET NAM, So nam 2014 www.cokhivietnam.vn NGHIEN CUfU-TRAO OOl Nhiet cdt dugc qua trinh gia cdng cao tdc chi rang nhiet cat tang giam gdc cdt va tang chieu sau