Nghien ciiu (S; JHaaHiffl
Dieu khien cac thong so cong nghe de dam bao chat iiTong be mat khi gia cong cac vat lieu co tinh deo cao tren may tien CNC
GS.TS. NGUYEN OAC LpC, TS. NGUYEN THANH NHAN,
Dai hoc Bach khoa Ha Noi
D
di vdl nganh Cd khf Viet Nam, trong nhung nim gan day dang ed xu hudng d3u tU eic io^i may gia cdng cit got hien <Jai, gia cdng tren miy dieu kh'en theo ehUdng trinh sd (NC, CNC, DNC ..,), hudng di dung din nay thUe sU da dem lai ket qua tdt dep.Tuy nhien, viec khai thac, sy dung d c may CNC v i o thye tien san xuat edn cd nhieu han che, thUc te cho thay la chat IUdng da dUde d i thien nhUng gia thanh ehUa giim, tham ehi d n eao hdn so vdi gia edng tren may van ning. Cd rat nhieu nguyen nhin nhung chii yeu l i ehUa dam bao cae thdng so cdng nghe phii hdp.
Kha ning lam viec cua ehi tiet miy chiu anh hUdng quyet dmh bdi d e thdng so ve chat IUdng be m i t lim viec, cac cdng trinh nghien cult (Ja chimg td ring chat lUdng be m i t ciia chi tiet khdng nhyng chju anh hUdng eiia nguyen edng cudi cimg ma cdn chiu inh hudng suot qua trinh gia cdng tao nen chi bet, Vi vay, mudn dat dUdc kha nang lam viee cd hieu qui nhat eiia chi tiet may, thi phii dim bio dUdc cac yeu d u ve chat IUdng be mit, de giai quyet dUde van de dd, ta phai tim dUde mdi quan he giife d e thdng sd cua ehat IUdng be m i t nhU Ra, Rz ,.. vdi d c thdng so cdng nghe nhU: c h e d d d t , thdng sd hinh hpc eiia dung c y d t . . .
1. G I 6 I THIEU DAC DIEM CUA
CONG NGHE CNC
Ra ddi vao khoang nhCTng nim 70 eua the ky XX, cdng nghe gia cdng cd khf tren may cdng eu dieu khien theo ehUdng trinh so NC, CNC (Computerised Numerical Control), den nay da thu dUdc nhiing thinh tUu vd ciing to Idn. Sir dyng may cdng cu, trung tam dieu khien bing chUdng trinh sd v i ky thuat vi xd ly NC, CNC trong d n xuat hing loat vii^
v i hang loat nhd da tao dieu kien Imh hoat hda va tUddng hda day chuyen gia d n g , nang cao chat IUdng v i ning suat gia d n g , dong thdi, lam thay iJdi phUdng phap va ndi dung chuan bi d n g nghe cho san xuat. May CNC ed nhyng UU diem so vdi d c may thudng nhU: Gia cdng dUdc d c chi tiet phye tap hdn; Quy hoach thdi han sin xuat tot hdn; Tap trung nguyen cdng eao va giam thdi gian phu; Tinh linh boat He dieu khien CNC (Computer Numerical Control)
THS. NGUYEN CHI CONG
cao hdn; Dp chfnh xac gia cdng on djnh, ddng a§u; Chi phf kiem tra giim; Chi phi do phe pham giim; Hoat ddng lien tyc nhieu ca sin xuat; Mdt cdng nhin cd the van hinh nhieu • miy cfdng thdi; Hieu suat cao hdn; Ting ning lyc d n xuat;
Cd khi ning tfch hdp trong h^ thong gia edng linh hoat.
Die diem chfnh eiia he dieu khien CNC l i d sy tham gia ciia may vi tfnh. Cac nha eh§ tao miy CNC d i d i t vao miy tfnh chudng trinh dieu khien cho tirtig loai may. He (Jieu khien CNC eho ph^p thay doi va hieu chinh d c chudng trinh gia edng chi tiet va d chUdng trinh hoat ddng d a bin than nd. Cac ehUdng trinh gia edng cd the dUdc nhd lai. Cic chUdng trinh cd the dUde nap toan bd hoic timg lenh mot t y ban dieu khien,
LTU diem: Khi l i p ehUdng trinh gia cdng hoic sii^ chij^
thuc hien ngay tren may tinh (khdng mat nhieu ehi phi, thdi gian lam bing lo, bing tiO- Khi ning tfnh bdn nhanh, chfnh xac ciia may tfnh eho phep xay dyng d c chUdng binh eon neng le, khi d n thue hien dUdc gpi vao chUdng trinh ehfnh nen giam bdt so d u lenh va thdi gian d n l i p trinh. Hau het d e may gia edng sy dung ky thuat CNC hien dai d n c6 man hinh dd hpa cho phep md phdng quy dao djch ehuyen dao khi gia cdng vi the giup cho ngUdi l i p trinh tranh dUpc sai xdt.
Ve ket d u chung may thdng thUdng, may NC, miy CNC deu cd phan ed sd than may, bin may, he thong truyen ddng true chinh, he thdng chay dao, he thong dieu khien, he thdng ga kep va cic thiet bi phy trd (lam mat, bdi trdn, chieu sang.,..).
2. MQT S6 KINH NGHIEM DIEU KHI^N CAC THdNG SO CONG NGHi KHI GIA CONG
Trong nganh cong nghiep, cac hdp kim 1162, T1C59-1, fll6T, AIMgj, SUS201, SUS304, dutfc sii dung khi phd bien de che tao d c d n pham ky thuit cao... Do vay, viec xac lap mdi quan he giCJa d c thdng sd che do d t ddi vdi cae vit lieu tren la vd ciing d n thiet de d i m bao chat ludng be mat chi tiet gia cdng m i thyt chat la dl xac lap quan hd giii^
d c thdng so edng nghe (iJiu vao), vdi chat IUdng be mat
Cau true may CNC May PLG-42 - Dii Loan oao tien CoROMANT-T-max P cua hang 5ANDVIK ^^V <^° <^Q nhim be m|t POCKETSURF cua My l g
40| KHOA Hpc SCONG NGH^ • (S6 10-&301S)
Nghien crru& mmiiigna
chi tiet gia cdng ((Jau ra), tir do cic nha cdng nghe dieu chinh d c thdng sd cdng nghe de dat dUde chat lUdng be mit d n pham theo yeu d u .
De xac djnh mdi quan h§ giu^ dp nham be mat va d e thdng sd cdng nghe ta phai tien hanh thUc nghiem bing each cho che dp eat thay ddi, sau do do dd nham be mat ifng vdl timg che dp c i t cu the, xir ly sd lieu nhan dUdc se Uiu dupe h i m hdi qui. De thu dUde ham hdi quy chfnh xac nhit ta phai tien hanh thUc nghiem, t u t la cho ehe dd eat tiiay ddi theo nhieu che dp khac nhau.
2 . 1 . Ket q u a thu'c n g h i e m gia cong cac hdp k i m / 1 6 2 , 1 1 C 5 9 - 1 , A 1 6 T , AIMgx, S U S 2 0 1 , S U S 3 a 4 tren m a y t i e n CNC ( P L G - 4 2 ) , d a o t i g n t i e u chuan, phu'dng t r i n h t h ^ c n g h i # m vdi cac v a t li£u t r e n :
- Vdi hdP kim ddng /162: Ra e3,9137.v- 0,04473.sl,629185.t0,052112 (pm)
- Vdl hdp kim ddng ;iC59-l: Ra - e4,37686.v- 0,316071.sl,20307.tO,032413 (pm)
Vdi hdp kim nhdm AlMg2: Ra - e6,29632.v- 0,52672.sl,506426.t0,079447 (pm)
- Vdl hdp kim nhdm fll6T: Ra e7,28660,v- 0,77626.sl,665243.t0,119538 (pm)
- Vdi hdp Uiep khdng gi SUS201: Ra= e4,93305,v- 0,73687.sl,001944.t0,357818 (pm)
- Vdi hdp thep khdng gi SUS304: Ra= e4,44518.v- 0,55689.51,001847.t0,385464 (pm)
2.2. Mot so nhan x e t chung cho cac loai v a t lieu tren:
Anh hudng ciia bUdc ben dao s den do nhim be mat (Ra) la Idn nhat, cdn tdc dp cat v va chieu d u cat t anh hudng hau nhu khdng dang ke,
Tdc (Jo d t V v i chieu d u d t t anh hudng den Ra ngUdc nhau.
Thdng sd bUde tien dao s anh hUdng den Ra cua hdp kim nhdm la nhieu nhat, v i t lieu thep khdng gi la ft nhat. VI thep khdng gl d ham IUdng Ni, Cr cao nen dp deo, dai cua thep khdng gi la khi Idn, khi gia d n g tien thUdng tao phoi day, ddi vdi hdp kim ddng va hdp kim nhdm khdng nen hliy tien chpn bUdc tien s ma phai nghien cun khao sat ky, trong thye te sin xuat, ngudicdng nhin thUdng phai cSt thy mau nhieu lan va kiem tra chat lUdng be mat trUdc khi san xuat loat.
Tdc do cat V anh hudng den Ra ciia hdp kim ddng la it nhat, hcJp kim nhom va thep khong gi xap xi nhUnhau. Thep khong gi va hop kim nhom cd do deo dai Idn hdn ciia hdp kim dong nen anh hUdng ciia v Idn hdn,
Chieu sau cat t anh hUdng den Ra cua thep khong gi la Idn nhat va ciia hdp kim ddng la it nhit. Thep khong gi d IUpng Ni va Cr cao, tinh dan hoi, tinh dec tUdng doi cap^
nen kha nang bien dang dan hoi, bien dang deo Idn, khd cat got, neu gia cong vdi chieu sau cat Idn rat nhanh mdn dao. Mat khac, neu cat vdi t qua nhd de xay ra tr\iat miii dao khi cat cung la nguyen nhan mdn dao, anh hUdng trUc tiep
den dp nham be mat, ;•:,.
Cung la hdp kim dong Latdng thdng sd btidc tien dao 5' anh hudng den Ra ciia /162 Idn hdn ciia /1C59-1, thdng so
I Mail ilmc ii^lii('m ii^rp kim diing Lalmig JI62
I Miiii lluic nghiem li^p l^im LuUm)iJli.'i9'l
Mihi llitfc nglii^m h(/p ldm niitim AlMg2 V, t ft hdn. Do trong J1C59-1 cd them ham lupng chi nen khi gia edng cimg che dp cdng nghe /1C59-1 thUdng de d t got.
Ra eiia nhdm fll6T chju anh hudng ciia bUdc ben dao s Idn hdn AlMg2, cdn anh hudng eua v, t it hdn. Tfnh deo dai CLia fll6T thap hdn AlMg2, khi gia cdng nhdm A16T thudng tao phoi day nhUng ft hdn AIMg2.
Ra eiia thep khdng gi SUS201, SUS304 chju anh hUdng cua eic thdng sd cdng nghe s, v, t tUdng dUdng nhau. Ddi vdi hai loai thep khdng gi nay trong thye te d n xuat ngUdi ta thudng phai u d i thien cd tinh trUde khi d t gpt.
Ket qua chi ra rang cd the dieu khien cic thdng so cdng nghe de dat dUde gia trj do nham be m i t chl tiet may theo yeu cau. Ve mat toin hoc ket q u i hoan toan cd the tin cay dUdc. Ve mat thye tiin ket qua thuc nghiem da dUde i p dung hieu q u i trong san xuat tai Xf nghiep Cd khf - Cdng ty TNHH MTV Hoi ehat 21 Tong cyc Cdng nghiep qudc phdng - Bd Qudc phdng, chat IUdng be mat chl tiet may dUdc dam bio, nang suat tanglen ro ret.
Y nghTa khoa hoc: DUa tren cd sd ly thuyet ket hdp vdi thUe nghiem, dUa ra dUdc ham toin hoc md ta mdi quan he giffa iJp nham be mat vdi eic thdng sd che do eat.
Dimg lam t i l lieu tham khao cho cae nha edng nghe, dieu khien ehe dp cat ciia minh dat dp nham be m i t chl bet theo yeu d u . Lam cd sd eho d c q u i trinh nghien ciftj khac, ho trd thiet ke, lap trinh d c phan mem dieu khien che dp d t .
Y nghia thu'c t i l n : Ket qua nay se ddng gdp them vao ngan hang tra cuU cho eic nhi cdng nghe, trong qua Irinh khai thie va sir dung miy tien CNC, de dam bio chat IUpng theo yeu d u va hieu
qui cao nhat. Ket qua nghien ciin cd the bo sung vao ngin hang dy lieu lim cd sd cho qua trinh nghien diu d c khfa canh khac ciia q u i trinh d t va lam tai lieu tham khao trong qua trinh dao tao tai nha trUdng.•>
TAI LIEU THAM KHAO
;. Tran Van Dich (2004), Cdng nghe CNC, Nhd xudt bdn Khoa hoc vd Ky thuat, Hd Noi.
2. Nguyen Ddc Loc (2005), Cdng nghe che tao mdy theo hUdng tU ddng hoa sdn xudt, Nhd xudt bdn Khoa hgc vd ky thudt. Hd N61.
3. Erik Oberg, Franklin D. Jones, Holbrook L Horton, Henry H. Ryffel (2004), Machinery's Handbook 27th Edition. Industrial Press Inc New York 4. Nguyen Phuang. Nguyen Thi Phuang Giang (2005), Casdtdddng hda trong ngdnh Ca khi, Nhd xudt bdn Khoa hoc vd Ky thudt, Hd N61.
Mdu lliuc nghi?m lif/p kimiili6ni/H6T
Mdu lliirc ngliiem ihep khong giSUS20l
I Man ihiK nghidm [hep I kliong gi'sUS304
2) 4 KHOA Hpc « CONG N G H | |41
