Tài liệu Cad/cam trong thiết kế và chế tạo

~3IAO TRINH -f f) J J0 -f}-JJ~-f J_~ 1 ~J l-J~ -fJ; r J_' ,~ ?" ,''- 50 GIAO Due . VA BAO TAO . HA NOI . TSKT. LUll QUANG HUY GIAoTRiNH '} CO SO CAD/CAM TRONG THIET KE vA CHE TAO • (PHAN 1) (Dung trong cac tnti'mg THeN) NHA XUAT BAN HA N (Minicomputer - Based) XuAt hi¢n tu nhfrng fiam 70 the ky xx, khi may tinh nho xuAt hi¢n nha vi¢c phat trien nhung m~ch rfch hqp co Ian LSI va nil 16n VLSI (Very Large Scale Integrated). • D(ic die'm: - Chi phi giam. - Kha nang li;lp trioh tt! do (khong bj nhieu IO<;lo chung). - Kich thuac nhb gQn. Ciu hloh h~ thong tren co so may tinh nho tUO'ng tv cau hinh h¢ thong tren cO so may tinh lan, nhung may tinh nho g90 han. l.3. H~ thong tren co sa may vi Hoh (Microcomputer - Based) May vi tfoh xuat hi¢n quang d~i boi Apple Computer dii co tac d¢ng ffi<;lnh tai linh vl,fc CAD/CAM. 51! tien bi? vtrqt tr¢i ella may vi tinh d. ohArr (PC) ella hang IBM dii 1<.1.0 dieu ki~n phat tTien nhieu ph~n mem CAD chi;lY lren Pc. • Di!c die'm: - D'.lt toe d¢ cao, kfch thuac nho g9n, dQ chinh xac cao. - Nhieu chuang trinh ling dl;mg duqc giii quy€t tot tren h¢ thong nay. 1.4. H~ thong tren H~ ca th6ng tren co nha.n nguai dung. CO' so tr~m cong tac (Workstation - Based) sa tr<:tm cong Hic duqc thi€t l~p vai cong ngh¢ cao cho • Dijc die'm: - Khi nang san sang cao. - Khi nang di chuy~n v~ tri linh ho~t. - Khii nang d¢c l~p hoan toan v6i nhii'ng nguai dung khac. - Hi~u suat cao, thai gian phan hoi ngan. - Nang luc da d~ng (da nang). - Khii nang de dang n6i m~ng v6i cac h~ th6ng khac. H¢ thong tren co trong tuong lai. sa tqm cong tac la co sa cho d.c h¢ thong CAD/CAM 18 2.GTCS CAD·B 2. Cae lhi"l b! dau vila (Inpul) 2.1. Ban phirn do ho~ (Key board) sa Ban phfrn do ho~ duqc thiet l~p tren co ball phim Cei ban (dung cho so'!-n thaa), nhung co them cae phfm chue nang rieng va c6 them chu¢1. 2.2. Bul quang di~n (Light pen) But Quang di~n t:,to kha nang linh ho~t Iga' ChQll, djoh vi d.c d6i tuqng ve tren man hlnh nha lay nguOi sir dl:mg tren man hloh wong taco But Quang di¢n duQ'c dung ph6 bien lrang nhli'ng oam 60 va 70 the ky XX, hi¢n nay it duqc dung. 2.3. Bang so hoa (Digitizing Tables) kern bUt dien (Stylus) Sit dl:mg thea hloh tuqng: Dung but chi ve len to' giiy trang. Trang twang hqp nay, dung but di¢n d~ vi: len bang 56 hoa. Nhb d6, de sii dl;l.og nhu thai quen ve va viet tren giay. Nguyen 19 thuang dung 18. dung sensor di¢n tir: Djch chuy6n ella cae thanh phan xac d~nh vi tri cila but di~n se t':10 nen twang di¢n tu l¢ch pha va dugc cae sensor tren be m<;lt bang thu nh~n. Bang so hoa co 2 vung: Vung ve va vung vao Menu I~nh. Ngoai lo~i bang dung sensor di¢n tir, con colo{li bang dung ky tlf (analog) va bang dung ky thu~t sieu am (acoustic). thu~t tuang 2.4. Chu(>t (Mouse) Duqe sang ehe cuoi nhfrng nam 60 the ky xx, den nay Ttlt ph6 bien do st! ti¢n lqi trang su d~ng v6i d.c bi~u tuqng va cac menu keo xu6ng (pull down) va keo len (pick up). C6 hai ki~u chuQt: Chu¢t ca khi va chUQt quang hQc . • ChuQt ca khi: Gam c6 1 h¢p, trang co 2 banh xe va can lan, m¢t bi cau aday. Nhb d6, co th6 xae d!nh vj tri cila can tro thea cae to~ d¢ X, Y ella no . • Chu¢t quang h9C: Sir d~ng ki6u ehu¢t nay bang cach di chuN len ban ca,m quang. 2.5. Can g~t (Joystick), qua diu danh dau (Track ball) 2.6. May quet (Scanner) May quet sir dVng st! phan X{l anh sang khi ehieu m¢t chum sang vao chfr 19 hay hinh anh d~ d9C chu hay hinh anh d6. Hinh dang va de) d~m nh~t cita chum tia phan x~ duqc me)t be) cam bien quang h9C bien thanh tin hi¢u di~n, qua cac be) ghep n6i bien d6i lUong tv - s6 (ADC), tin hi~u dUQc dua van computer. C6 2 d~ng may quet thuang dung: • May quet dung be) d9C quang va tir quang. • May quet dung be) d9C h6ng ngo~i va lade. 3. Cae thiet b! dau ra (Output) 3.1. Man hlnh Man hlnh d6 do hoa (Graphic Display - Monilor) ho~ la thiet bi dau ra thu~n ti¢n va kinh te nhat. T6 hqp man hinh va ban phim duqc g9i la thiet bi dau cuoi d6 ic terminal) toi thi~u cua me)t phl'in cung CAD. ho~ (graph- 3.1.1. Mim hinh den trang Ok phuong phap hi~n thi: • Gng tia am c~c (CRT - Cathode Ray Tube) - dung milO hinh khang ph&ng la chu yeu. • Hien thi tinh the long (Liquid Cristal Display), • Hi~n thi Laze (Laser Flat Panel Display). • Hi~n thi Plasma (Plasma Panel Display). • Hien thi lap mong (Thin Film LED Display) (LED - Light Emitlion Diode): Dung diat phil quang. 3.1.2. Mim hinh mau Phoi mim: Dung 3 mau co bim: do (R-red), xanh 10 (B-blue) va luc (G-green) d~ phoi hqp t~o nen cuang de) mau, nghia la t~o ra cae mau sac khac nhau. • Dung tin hi~u so (digital): C6 16 mau t6ng hqp (vi d~: dung card HCHercttle Colour). • Dung tin hi¢u so chuy~n d6i thanh tin hi¢u lUong tl!: + Co 64 mau (vi d~ dung card XGA - Extended Graphic Arrays). + Co 256 mau (vi d~ dung card VGA - Video Graphic Arrays; dung card TIGA - Texas Instrument Graphic Architecture). 20