NGHIEN cuu-TRAOD6I T | LFU HOA CHi DO CAT KHI TIEN Hgp KIM TITAN TI-6AL-4V OPTIIVIIZATION OF MACHINING PARAIVIETERS IN TURNING OF TITANIUM ALLOY TI-6AL-4V Tr^n Van Khigm Tnidng Dai hpc Su pham Ky thuit Nam Dmh Hap kim Titan (HKTi) Id vdt lieu cd nhiiu tinh chdt ca ly, hod quy nin duac img dung rpng rdi nhiiu ngdnh cong nghiip, dgc Met Id ngdnh Hang khdng vu tru Tuy nhiin, day ciing Id vgt lieu ddc biit khd gia cdng, cho chdt luang be mat thdp vd mon dao nhanh Di chpn che dp cat hap ly cho HKTi, van dp dung duac cdc md hinh vd phuang phdp tdi uu hoa (TlfH) thong dung, nhung phdi tinh din day du cdc yiu td dgc thii cua HKTi, do bdi todn phitc tgp vd khd gidi Bdi bdo gi&i thiiu md hinh TlfH chi dp cdt tiin hap kim Ti-6Al-4V, mpt logi vgt lieu diin hinh trin cdc thiet bi hdng khong - vd tru Md hinh todn hoc co tinh den chi phi mua vd mdi dung cu, tudn theo diiu kien giai hgn nhdm bi mat vd tuoi bin cua dung cu Kit qud thuc nghiim vd tifih todn dua duac chi cdt tdi uu, dgt chat luang bi mat cho tru&c, tuoi bin cua dung cu dung bang tuoi ben kinh ti vd chi phi tdng thdp nhdt Cdc thong sd tinh todn: Ty le chi phi cho dao lan (chiem den 40,8% tdng chi phi gia cdng), chdt luang bi mat thdp, tuoi bin dung cu ngdn phu hpp v&i dgc diim cong nghi cua HKTi Tir khoa: Chi dp cdt, tdi uu hda, quy hogch tuyin tinh, hap kim Titan ABSTRACT With many mechanical, physical and chemical properties Titanium alloys are widely used in a wide range of industries, especially in aerospace However, these materialsare particularly difficult to machine, resulting in low surface quality and rapid tool wear In order to select a suitable cutting parameters for titanium alloys, despite employing common optimization models and methods, it is necessary to take into account all their specific attributes; therefore, the problem is complicated and difficult to solve This article introduces a model for optimization ofthe cutting parameters in turning ofTi6AI-4Valloy, a typical material in aerospace devices The mathematical model takes into account the cost of tool purchasing and grinding, subject to the constraints of surface roughness and tool life Experimental and computing results provide optimum cutting parameters, satisfying the given surface quality, the equality between actual and economic tool life and the lowest total cost Computing parameters, such aslarge tool cost (accounted for 40.8% of total cost), low surface quality, short tool life agree with the technological characteristics of titanium alloys Keywords: Cutting parameter, optimization, linear programming, titanium alloy ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, Sd nam 2017 www.cokhivietnam.vn '^ MGHIEN c u u - IKAUUUI I.DATVANDE gin toi uu; Hgp kim Titan cd uu diem die biet: Mhe xip xi mdt nua thep nhung cd ben irong duong, tri dugc ca tinh d nhiet :ao va khdng gi frong cac mdi trudng an mdn hoa hpc Vi vay, cic HKTi khdng the tiiieu iugc frong cdng nghiep hoi chat, dugc pham, thuc phim, hing khdng vii tru Tuy nhien, :d dp deo, dai ldn, din nhiet kem nen day :ijng la hgp kim die biet khd gia cdng Khi gia Ddng chiing, luc cat ldn, nhiet dp cao, dung cu bi mdn rat nhanh - Khdng xet din cic dieu kien ranj budc, khien y nghia thuc tien cua ket qui tin dugc bi han che Khi gia cdng cac vat lieu khic, nhieu chi phi cho dung cu cd the bd qua dugc Nhung gia cdng HKTi, thudng phai sir dung dao dat tien, dung cu lai mdn lihanh nen thdi gian thay va mai dung cu dang ke; chi phi mua va mai dung cu ldn Thuc te dd anh hudng den viec chpn va tdi uu hoa ( T U H ) che cit Vdi cic vit lieu thdng thudng, che dp cit chu yeu dim bio chit lugng gia cdng, nang suit va chi phi true tiep gia cdng Khi gia cdng HKTi, ngoai cic yeu td fren cdn phai tinh den thdi gian, chi phi va tudi ben ciia dung cu nen frong md hinh TlTH :he dp cat HKTi, c i ham muc tieu lan he rang budc deu phiic tap, khien bai toin khd giii hon nhieu Du thl, TUH chl dp cit HKTi vin li trudng hop cu the cua bii toin TUH tdng quit, :d md hinh toan hgc v i cac tiiuit giai da duac :dng bd rdng rai [1] Trong bai bao trudc [2], :hiing tdi ciing gidi thieu phuang phap Tagu;hi v i ling dimg frong TUH chl dp ck Phuong phip Taguchi cd nhieu uu dilm, nhung ciing ;dn tai nhihig nhupc dilm cd him, frong dd: - Ldi giai tdi uu chi dupc tim frong so :ic dilm thi nghiem rdi rac, nen tiiudng chi De giai cic bai toan T U H tdng quit vi sat thuc te, cd diy du him muc tieu v i di6i kien rang budc, phii iing dung cac thuat toai va cdng cu T U ^ chinh thdng Hien dang d su bung nd cic md hinh tien tien, cd trinh df tu ddng hoi cao, dien hinh li cic md hinh tini toin tiln hoa, nhu giii thuat di fruyen (GA) [5] TUH din kiln (ACO) [ ], T U H biy dan (PSO; [4], mang no ron nhin tao (ANN) [3], xir I; nhanh v i du chinh xac Tuy nhien, de cd ca sc tin cay so sanh, chgn cic phuong phap, chiinf tdi xuat phit tii phuong phip truyen thong diing cdng cu thdng dung, dl ding tiep cin vi kiem soat Dd la phuong phip quy hoach toai hpc, dimg phin mem Microsoft Excel TONG QUAN VE BAI TOAN TOI Ut HOA CHE DO CAT Bang toin hgc, bai toan TlfK tdng qua: dugc phit bieu nhu sau: Cue tieu hoi ham mu( tieu (a) vdi cic dieu kien ring budc (b) '"iny^[y,(:i).y/x)f h = [^rsJ.-''™:r3ij]'=0 (a) (b) Trong do, x = [Xj X x ]'^ - Vecto cac bien dau vio, ciing l i bien dieu khien;; "^ [y, yj yJT - Vector muc tieu, gdm cai phan bieu dien cac tieu chi tdi uu Tron] (b), lin lugt la rang bugc dang bit ding thuc dang dang thiic v i dilu kidn bien Neu bai toa] la TLTH mdt muc tieu thi vector y chi cd mo phin ISSN 0866 - 7056 TAP CHi CO KHi VlfiT NAM Sd nam 2017 NGHIEN CU'U-TRAODOI 2.1 Md hinh toi mi hoa che cat 2.2 Ham muc ti@u Hinh 1, bieu diln quan he thii bic cua cac dai lugng frong qui trinh gia cdng Chl cat l i cic dai Iugng dau vio Chimg anh hudng true tiep den cac thdng sd cua qui frinh: Tdc dp bdc vat iieu (Z), tuoi bin cua dung ci^ (T), dp nhim be mat (R^), luc cit, nhiet dp viing cat, cdng suat tieu hao, Tilp theo, Z, T, R^ lai inh hudng den muc tieu co ban cua qua frinh gia cdng (nang suit, chit lugng, chi phi) Mpi qua frinh san xuat deu nham vao tieu chi: Nang suit, chat lugng v i chi phi Nhung thudng cic nhi san xuat cd ging dat chat Iugng yeu cau vdi nang suat cao nhit, chi phi thip nhit, khdng phin dau dat chat lugng cao nhit bang mgi gii Vi viy, it cac thdng sd chat Iugng dugc dua vio ham muc tieu Hai muc tieu thudng dimg la nang suit cao nhat va chi phi thip nhat 2.2.1.Muc tieu nang suat gia cdng cao nhat Ning suit gia cdng cao nhat cd the dugc the hien bing tieu chi: The tich vat lieu dugc cat frong mot dan vi thdi gian cao nhat: Z=v.s.a —* max (2) Hoac thdi gian chinh T^ nhd nhat: T„=V/Z^min 1^ Hinh Cdc dgi lupng cda qud trinh gia cong i Tir md hinh toin hgc (1) v i hinh I, cd thl md t i bing ldi bai toin T U H che dp cat nhu sau: Xie dinh bp thdng sd che dp cat v, s, a cho cac ham muc tieu: Nang suat, chat ] lugng, chi phi dat gia tri cue tieu (hoac cue dai), vdi dilu kien rang budc, cic thdng sd I cdng nghd Z, T, R^, frong gidi han cho phep ll De xay dung md hinh toan hgc cua bai toin, chiing ta phii tiiilt lap dugc cic mdi quan ; he ham sd giiia cac ham muc tidu, cac dieu kien rang bupc v i che dp cat (3) Trong do, V (cm^) - Thetichvat lieu bi cat Cic tieu chi fren chi the hien nang suit gia cdng true tiep, chua tinh den cac thdi gian hao phi khac D I dinh gii toin dien han ning suit gia cdng, ngudi ta diing tieu chi thdi gian nguyen cdng nhd nhat: -To+Tp,,+T,^+- • (4) Trong dd, TJ^\i)- Thdi gian phy - T ^ Thdi gian mii dao; T^^ - Thdi gian chuan bi, ket thuc loat gia cdng; n - Sd lugng chi tiet frong loat T , T^j, va n khdng phu thudc che dp cat, cd the bd qua tinh toin che cat Chi*^^ ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, Sd nam 2017 www.cokhivietnam.vn MGHieNGlJU-TRAO DOI - K^ l i ehi phi mua dao, tinh eho ca nguyen cdng tieu (4) tra thanh: T V t J (5) Ky^ Trong do, t^- Thoi gian cho mgt Ito mai dao; T - Tuoi ben cua dvmg cu D6 dl so sanh va trao d6i kSt qua nghien ciiu, ngudi ta thtrcmg dung thai gian gia cong don vi thS tich vat U$u phoi: V Z (6) ZT - K^^ Ii chi phi mai dao tinh cho ca nguyen cdng: _AT„ Tu6i ben ciia dao dugc tinh theo cong thuc Taylor; r = Qv"s"'a" (7) Thuang thi cac s6 mu deu am va Imtj > nt| > llct| nen anh hucmg cua s va a thuang dugc bo qua Thay (7) vao (6) va chii y ring Z=v.s.a (cmVph), dugc ham muc tieu, co tinh den mon dao V vsa C^v°""s""'a"*' (8) z T~ T Vdi z - Sd lin mai dao frong toan bo thdi gian su dung dao; B^ - Chi phi mua dao (U); B=B /z - Chi phi mua dao tinh cho chu ky mai _AV ^CV ^ Vdi t^^ - Thdi gian lan mai dao; C=A., t^j - Chi phi cho Iin mii dao Cgng ca phin, ta nhin dugc cH tieu tli mi theo chi phi gia cdng: ^ AV BV CV K— v ZT ZT >min Vi B va C dIu la hing sd va cimg thit nguyen nen cd the gdp chiing vao hing sd Cj (chi phi mua va mai dao cho chu ky mai) Vi viy, chi tieu tdi uu cd thl dugc viet lai duoi dang don giin han: 2.2.2 Muc tieu chi phi gia cong nhd nhdt j f = i I +£ ^ ^ „ ; „ Z Chi phi gia cdng la chi phi cho c i nguyen cdng: Nguoi ta ciing thuang dung chi phi de gia cong 1cm' vat lieu, tu c6 chi tieu K=K^+K,+K^, (U) (lo: V Trong dd, K^ la chi phi van hanh may; U la viet tat cua dan vi tien te, cd the la USD, ng.d., bay tnrdng hgp AV (9) ZT Z* ZT Thay (10) vao (9) ta nhan dugc han muc tieu co tinh den m6n dao: , voi A (U/ph)- Chi phi cho phut chay may; 2.3 Cac dieu kien rang bufic ISSN 0866 - 7056 TAP CHl CO KHi V I E T NAiM, S6 nam 2017 NGHIEN CO'U-TRAO DOI Cac dieu kien rang bupc dam bio eho cic nghiem tim phu hgp vdi thirc tl Sau day md t i mpt sd dieu kien ring budc thudng gap Theo y nghia, chung dugc phan nhdm - Mien gidi ban tdc dp cat cua may: - Mien gidi ban lugng ch^y dao: 2.3.1 Nhdm cac yeu cau ky thugt cdn dat (17) - Dieu kien han che ve dp nhim be m^t: R^=R,v"'s-a''