Xây dựng phần mềm cắt lớp cho máy tạo mẫu nhanh

NGHIEN Ctfu - TRAO D6\ XAY DUNG PHAN MEM CAT L O P CHO MAY TAO MAU NHANH SLICING SOFTWARE FOR RAPID PROTOTYPING MACHINE KS Bui Anh Qudc, PGS.TS Dang Van Nghin, KS Nguyin Thanh Quang, KS Ta Van Chinh DCSELAB, Trudng Dai hgc Bich BQioa TR Hd Chi Muih T6M TAT Cdng nghe tao mdu nhanh Id cong nghi too mdu diia trin nguyin tac ddp ldp Cdc ldp ndy, dUdc xay dung diia tren diidng contour Ciifl tiing ldp mat cat vat the Chinh vi vdy, chung toi xdy dung phdn mim ndy di tao contour cita titng ldp mat cat vat thi trin file STL - Id mot dinh dang chudn a i a tgo tn&u nhanh Sau dd, xudt dU lieu cho qud trinh diiu khien vd gia cdng trin mdy tao mdu nhanh Tif khoa: Tgo mdu nhanh (TMN); Stereolithography (STL) ABSTRACT Rapid prototyping technology is prototyping technology based on the principle of covering layers These classes are based on cross-sectional contour of each object class Therefore, we built this software to create cross-sectional contour of each object class in the file STL - is a standard format of rapid prototyping Then the data for process control and process rapid prototyping machine Key words: Rapid prototyping technology; STereoLithography (STL) I.GIOITHIEU 2.M6TA Cdng nghe TMN ngiy cing phit tren vi da khing dinh duoc vai trd quan trgng ciia minh qui trinh sin xuit TrUdc sU phit triln cia cdng ngh^ chl t^o, vit li^u vi dilu khiln nUdc thi vile chl tao mdt miy TMN la thich thic nhUng khdng phii li dilu xa vdi Bii bio niy nham hide diu lim quen vdi nhing thich thic dd li xiy ding mdt phin mim cd ning xiy ding lai md hinh 3D ti dinh dging STL vi thUc hien chia ldp theo phUdng true Z de cho biln dang cia ting mat cit cua chi tilt 2.1 Gidri thieu cau tnic dfl; lieu STL Dinh dang STL (STereoLithography) hing 3D Systems phit trien t i nam 1987 li djnh dang duoc phd biln cic h$ thdng tao mau nhanh Dinh dang STL luu tri dfl Ueu mo hinh 3D d dUdi d ^ g tip hop cic tam giic Cic tam giic niy digc xic dinh bdi tga dd dinh (vertex) vi mgt phap tuyln don vi (facet normal) nhim phin biet hUdng vit lilu (phin nim bin vi bin ngoii cua miu), chilu cia vecto phip tuyln li chieu hidng be ngoii be mat cua md hinh "^ TAP CHl CO KHl VIETNAM • Sd (Thing nim 2013) ^ B NGHIEN Ctfu-TRAOQ6I dinh cua c i c tam giic (dit theo t h i t i b i n tay phii he tga dp Decac chilu) Q u i trinh dgc file STL se l i n l i o t doc tga dp vee to p h i p tuyln vi tpa dp dinh cua cic tam giac, c i c gia tri niy se d i d c s i dijng cho qua trinh h i l n thi ddi tipng Hinh 1: Cdu true cua Facet File STL cd kilu dmh dang ASCII v i dang nhi phin (Binary) • Dang ASCII: cd dung lUOng ldn hdn dang nhi phin nhUng cd can t r i e don giin v i rd ring nen cd t h i dgc hilu n h i mdt v i n bin Bd ky t i ASCII gdm 256 ky t i d i o c phin bd n h i sau: 32 ky t i d i u tiln l i ky tU dilu khiln Cac m i ASCII 32-47, 58-64, 91-96 va 123-127 li ky tu die bilt nhu dau chim, dau phay Cie ma ASCII 48-57 l i 10 c h i sd Cic ma ASCII 65-90 l i cic c h i cii hoa ti A-Z Cac ma ASCII 97 -122 la l i cic c h i cii thidng t i a-z • Cac m i ASCII t i 128-225 l i cic ky tU dd hga WPF, mpt cdng nghe tiln tiln % trinh tren he dilu h i n h windows, d i o c s i dung phan mem D i d i day l i md hinh phin cip cic ddi t i p n g c h i o n g trinh: B Qua trinh Men thi doi tiidng dttdc thilc hien nhii sau; • Dang nhi phin (Binary): S i dung cie sd nguyen v i sd thUc theo tieu chuan IEEE (Institute of Electrical and Electronics Engineers) WPF cho phep chiing ta xiy dUng doi tiong p h i c tap t i tip hop cac tam giic (Triangle3D|, mdi tam giie bao gdm tga dinh (Pomt3D) 2.2 Thuat toan doc file STL v i mdt vecto p h i p tuyln ( d i o c gin ngim dinh q u i trinh dgc file) Tap hpp cic tam giac • Thuat toin doc iile STL dang ASCII: sl hinh t h i n h nen l i d i cic tam giic (Mesh3D) Do cau true cua file dang ASCII rd ring nen thuit C h i o n g trinh cd k h i nang hien thi dipc nhien toin don gian la n h i n dang cic ky tU, I i u tga ddi t i p n g nen chiing ta se cd nhieu cic ddi tli:?ng cac vecto normal, vertex dgc diOc cac biln x, y, z Mesh3D, cic ddi t i o n g Mesh3D niy se thdng qua mdt doi tiOng ldn Model3D.de d l ding quJn • Thuit toan dgc file STL dang Binary: li ModelVisual3D se quy dinh vile hien thj dfi dgc 84 byte eua file sau dd dgc d i lieu cua t i n g t i p n g (thdng sd m i u , c i d n g dp chilu sing ) va facet cho din hit (dfl lieu moi facet c h i a 50 cudi cung tdi ddi tUOng ViewPort3D se la ndi d^ byte) Liu lai ming (Array) t h i hien ddi tupng can dupe hien thi (ddng vai tro n h i m i hinh de chilu) 2.3 D i n g mo hinh 3D File STL md t i b l mat vit d i g c tam giie hda phi ciu true thdng qua phip tuyln don vi v i TAP CHf CO KHi VIET NAM • Do d i e t r i n g eiu true file STL nen kW thUc hien dgc file c h i n g ta se cd lan lUdc cac gia tri S6 (Thing n i m 2013) NGHIEN C0rU-TRAOD6l toa dp cua vecto phap tuyln va dinh cua tiing tam GiOa mat phang cat v^ eae facet co t h i xay giac doi tilong Point3D dUOc sii dung de gan cac tnfdng hpp sau; gia tri dinh (vi m6i facet file STL co dinh va xSy diJng tam giac d l hiln thi WPF eiing TrUdng Vl tri cac dinh Phan giao can CO dinh), chiing ta st dung them mot doi hop tuong VectorSD duoe xay dUng sin WPF I M6t dinh nam tren Doan thang di gan gia tri vecto phap tuyen doc cac facet (hoac dudi) hai dinh (mpt canh cua file STL Cii nhif vay, moi lan dpc diioe mpt nam mat p h ^ g cat tam giac) facet ehiing ta lai t^o mpt tam giac de hien thi II Doan thang (di M6t dinh nam tren, troi^WPF mpt dinh nam dU6i, qua dinh cua mpt dinh thupc mat tam giac thupc phang cat mat phang cat) III M6t dinh nam tren, hai dinh nam du6i Doan thang hoac ngUpc lai IV Ba dinh nam tren (hoac dudi) mat phang Khong giao cat V Diem (dinh cua Hai dinh nam tren tam giac thupc (hoac dudi) dinh mat phiing cat) thupc mat phang cat VI Ba dinh thupc mat Ca tam giac phang cat Hinh 2: Giao diin cua chUdng trinh 2.3 ThuSt toan chia ldp file STL D l thUe hien eat ldp file STL thi c6ng vile dau tiln la ta phai giai quylt dupe 1^ tim dUOc giao dilm ciia cac facet va eac mat phang cat khong gian NhU trinh bay phan trin thi file STL bilu dien chi tilt dUcfi dang tap hpp cac facet, m6i facet bao g6m dinh (vertex) va phap tuyln (normal) eua facet do vile tim giao dilm cua cac facet va mat phang eat ehinh la bai toan tim giao dilm cua mpt tam giac va mat phang khdng gian Cac trUdng hpp I, V, VI thi ta xac dinh dupe phan giao giiia facet va mat phang cat Con trUcfng II va III can tinh tpa dp hai dau doan giao eua facet va mat phang cat Vi du cho mp facet nhU hinh 5, gpi (X , Y, Z ) la tpa dp giao dilm cixA mat phang cdt vdi canh v,, /^ x„—v., v„-v.„ z -V, , , Taco:-^ '-^^^ ^ = -^ ^ = /(0