'IdGHIEN CUU • TRAO DOI
KHAO SAT CAC YEU TO HINH HOC CUA BE MAT PHOTC TAP TRONG KY THUAT CO KHI
THE INVESTIGATION OF DIMENSION FACTORS OF COMPLEX SURFACE IN MECHANICAL ENGINEERING
Hoang \i, Vu Nhii Nguyit TrUdng Dai hpc Ky thuat Cdng nghiep Thai Nguyin.
TOMTAT
Tgo hinh be mat chi tiit dgt do chinh xdc cao dong vai tro quan trgng trong ki thudt ccf khi. Phdn tich tinh todn thiet ki Id bUdc quan trgng ddu tien trong qud trinh tgo hinh mgt sdn phdm, doi vdi chi tiet CO cdc yeu to hinh hgc kho xdc dinh. Sd df nhU vgy Id vi no quyet dinh dp chinh xdc kich thUdc, hinh ddng vd chdt litgng be mat gia cdng. Bdi bdo ndy noi ve vdn dephdn tich thiit kivd khdo sdt cdc be mat chi tiet hinh hgc phdc tap. Viec khdo sdt vdi sU ho trd ciia cdc phdn mem MasterCam vd MatLab. Kit qud nghien cdu dd dUa ra gidi thudt dexdc dinh dUdc cdc thong so hinh hgc cua be mat. Cdc kit qud ndy Id cd sd quan trgng cho qud trinh ilng dung cdng nghi CAD/CAM-CNC gia cdng cdc hi mat phdc tgp trong ky thudt. Them vdo do, cdc kit qud nghien cdu co the dng dung trong qud trinh ddo tgo vd hd trg cho viic lap chUdng trinh gia cdng cua qud trinh sdn xudt hien dgi.
ABSTRACT
The machined surfaces forming with high accuracy has an important role in mechanical engineering.
The designative analysis and designative caculation are the first important step in the machined surfaces forming. This is because it determine accuraccy of surface's dimension, shape and quality. This paper presents designative analysis and investigate complex surfaces. The investigation was aided by MasterCam and MatLab. The results were good solutions for dettermination of geometry factors of surfaces. They were an important establishment in the applied CAD/CAM-CNC technology for complex surfaces machining in technique. Moreover, they will also be applied in education and morden manufacturing.
1. GlOl THifiU rat da dang. Chiing cd thi cd cau tao ddn gidn nhU la bl mat phang, mat tru, mat cdn... hoac cau tao Tgo hinh bl mgt chi tilt mdy dat dp chinh hinh hpc phdc tap nhU be mat cua chi tiet khudn xac cao la yeu cdu cdp thilt trong ki thudt che tao mau due, gia cdng dp lUc, than, vd xe may, d td, may may. Vifc khdo sat cdc ylu td hinh hpc cfla bl mat bay..Cho din nay dd cd kha nhieu nghiin cdu vl ddng vai trd quan trpng trong vifc chpn gidi phdp tao hinh be mat chi tilt nhU phUdng phap tao hinh, cdng nghl tgo hinh dat dUpc cac ylu cau vl dp thiet hi, chl dp cdng nghf, phan tich thiet kl, ddnh chinh xdc hmh dang hinh hpc. Cau true hinh hpc gia thilt ke, tdi Uu hda thilt ke, thdng sd gia cdng, cac bl mat dUpc sfl dyng trong cac nganh ky thudt dac tinh cua bl mat, vat lieu, tudi thp cua dung cu'^
T^P CHf CO KHf V I £ T NAM • Sd 6 (Thdng 6 ndm 2013)
NGHIEN CUU-TKAUeOI cat [1],[2],[3]. Trong dd vifc phdn tich, khdo sat cdc thdng sd hinh hpc bl mat la cd sd quan trpng cho viec chpn chl dd cdng nghe che tao chi tilt 14], Trin cdc mdy cdng cu CNC, cd the coi bl mat gia cdng dUpc hinh thdnh bdi tap hpp cac dilm tilp xuc gifla profile lUdi cat cua diong cu vdi bl mat troi^ qud trinh gia cdng. PhUdng, hudng cua van tdc cat, v^n tdc chay dao ciing nhfl phan lUc cua qua trinh cat tgi diem tiep xuc vdi be mat...
la cdc ylu to anh hudng tnic tilp din chat lUpng tgo hinh be mat. Cdc ket qua nghiin cflu dudi day nham xac dinh cdc yeu td hinh hpc cua be mat gia cdng nhU dp cong, dp xoan phap myln, tilp tuyln va cdc gid tri gidi ban cua chiing Iam cd sd dl lap trinh trong tgo hinh bl mgt bang gia cdng cat gpt.
2. CO sd T O A N
Mdt bl mat cung cd thi bilu dien bdng rad hmh hinh hpc nhfl tren Hinh 1:
Phdn tich tinh toan thiet kl Id bUdc quan trpng trong qua trinh tao hinh rapt san phdra.
Ddi vdi chi tilt cd cdc ylu td hinh hpc khd xdc dinh, yeu cau nay Igi vd cung quan trpng vi nd quyit dinh dp chinh xdc kich thudc, hinh dang va chat lUpng bl radt gia cdng. Dl phan tich thiet kl bl mat hinh hpc can quan tdra den cdc ylu td hinh hpc cfla nd nhU tilp tuyln, phap tuyen, dp cong, dp xoan, va cdc gid tri gidi hgn cua viec lUa chpn cac thdng sd cdng nghe gia cdng hpp li bao gdm kich thudc dao, kieu dao, cac thdng sd gd ddt, phuong phap gia cdng, dieu khien qua trinh.
Bl mat bat ky trong ky thudt cd thi bilu diln theo md hinh todn sau [41:
P(u,v) = Ix y zY = [x(u, v) y(u,v) z(u,v) f
< u < u ,v < v < v .
(1)
Trong dd:
x,y,z - Id tpa dp cfla diem tren bl mat theo 3 phuong.
u,v - Id tham sd cua mdt tpa dp.
Hinh 1: Md hinh hinh hgc vd cdc yeu to hinh hqc tren bi mat chi tiet.
Cic thdng sd hinh hpc can thiet cua be mgt:
Vecto tilp tuyln tai 1 diem P(u,v) trin bl mat xac dinh bdi cdng thflc sau:
2.1.Cdcylutdhinhhoccuablm^tgiacdng P (u,v) _^_dx_.
du du
dy . dz ,
du du (2)
„ , . dP dx . dy . dz , (3) P (u,v )= — = — i + ^ - j - ^ — k
" dv du 8u du
Vecto xoan dUflc tinh theo cac yeu to til he toa do vuong goc nha sau:
' B^x d^y d^z' dudv dudv dudv d'x . d^y . d^z ,
1 + ——j + k
5wt)v chidv dudv (4)
Vecto xoan phu thu6c vao cac dac diem hinh hpc be m^t va cac thong s6 cua no.
N(u,v)
Vecto phap tuygn tai mpt diem:
8P 8P „ „
= PuxPv (5)
du dv
Khoang each gifla hai dilm P(u,v) va P(u + Av, V + Av ) tren bl mat chi tiet (hinh 2) dUpc xac dinh bdi cdng thflc sau:
S = f' ^Ew^l^Ftr^^^^ dt (6)
Dp cong cua hi mat tai mpt dilm tren mat cat cong thong thadng dapc xac djnh bdi cong TAP CHl CO KHl VIET NAM • 85 6 (Thang 6 nam 2013)
NGHIEN Cljru-TRAO Ddi
cdng thflc sau:
Lu' +2MU-V +Nv
Md hinh va gid tri cua cdc ylu td hinh hpc b l mat gia cdng la dfl heu can thilt trong tao hinh (7) b l mat theo cdng nghe CAD/CAM tren cdc may
CNC.
Tren cd sd todn cua be raat neu tren, gidi thudt d l giai bai toan da dUpc xdy dUng (Hinh 3).
Thugt gidi nay cd t h i flng dung cho cac bp ndi suy hinh hpc trong cdc phan mem CAD/CAM, may CNC nham xdc dinh cdc ylu to hinh hpc b l radt tin cay va chinh xac.
3. THU'C NGHlfeM
Hinh 2: Khodng cdch tren be mat.
Bdn kinh cong tai mdt d i l m tren b l mat dfldc xac dinh bdng cdng thflc sau:
Chpn mdt b l mat cua chi tilt khudn raau, tiln hanh do, md hinh hda va md phdng be mgt t r i n may do tpa dp CMM cung ho trp cua cac phan mem MasterCam va phan mira MatLab.
(8) 2.2. Xdc dinh m o hinh vd gid tri ciia cac yeu td hinh hoc cda b l mat
Hinh 3. Stf ddgidi thudt xdc dinh cdc thong so hinh hgc be mdt.
Hinh 4. Be mat chi tiet thd nghiim.
Theo cac bUdc nhU sd do thudt todn, nghien cflu da chpn b l mat rapt khudn mau (Hinh 4) de phuc vu qua trinh khao sat cdc yeu td hinh hpc cua b l mat nham dUa ra bd thdng sd hinh hpc phuc vu budc lap trinh gia cdng vd chpn thdng sd cdng nghe.
Kit qua xdc dinh cdc thdng sd hinh hpc cua b l radt chi tilt nhU sau:
Gdc hpp bdi phap tuyln va phUdng thang dflng Idn nhat la:
u _ , . = 90.0232
Gdc hpp bdi phap tuyen va phUdng t h i n g ^
T^LP CHf C O KHf V I | T NAM V Sd 6 (Thdng 6 nam 2013)
NGHIEN COfU-TRAOeOl
dulng nhd nh(!t ik:
Gdc h(jp bdi mjt phing ti(fp tuy& cCia bl mjt chi tlft v4 mjt phing bin mdy ldn nhSt:
a „ „ =-0.0031
Gdc hdp bdi mjt phSng ti4p tuyfo cia bl mjt chi lift vJ mjt phSng bin miy nhd nhit:
Bin Wnh cong ldn nhit cila bS mjt theo 3 phUdng x,y,z lin lUdt li:
, = 4.6613e+005 . = 3.9895e+005 P™I!=l.t"'57e+D04
Bin kinh cong nhd nhit cita bl mjt theo 3 phadng x,y,z lin lUdt li:
P„,„ = -l-3026e+006
-1.1621e+006 -3.5466e+004 4 . l d T L U ^
Kft qui nghiin ciJu da dUa ra giii thu Jt vi utng dung dl xdc dinh cdc thdng sd hinh hpc cCia bl mjt. Ddy li cd sd quan trpng cho qui trhih i3ng dijng cdng ngh| CAD/CAM-CNC gia cdng cdc bl mjt phiJc t?ip trong ky thujt. Kit qui nghiin cilu cd thi ijng dyng hi|u qui trong die t^o Vi h6 trp cho IJp trinh gia cdng cila qui trinh sin xudt hi|n d»i. lUy nhiln cin tilp tyc hoin thi|n nghiin cilu theo hudng phdt triln phdn mim n$i suy hinh hpc. •
Ngiy nhjn bii: 15/5/2013 Ngiy phin bi|n: 10/6/2013
NgUdi phin bl^n: PGS, TS. Vu Ngpc Pi, TVUdng D?i hpc Ky thuJt Cdng nghi|p Thdi Nguyin.
Til Ufu tham khio:
[1]. Y.Quinsat, L. Sabourin, C. Lartigue, Surface topography tn ball end milling process: Description of 3D surface roughness parameter, lournal of materials processing technology 195, pl35- pl43,2008.
[2], YtLu. Yoshtnl Takeucht - Ichiro Takahashi - Masahiro Anzai, An integrated system development for ball md mill design, creation and evaluation, Int I Adv Manuf Technol 25, p628- p646, 2005.
[3], Zezhong C. Chen; Gang Liu, An Intelligent Approach to Multiple Cutters of Maximum Sizes for Three-Axis MllUng of Sculptured Surface Parts, Department of Mechanical and Industrial Engineering, Concordia University, Canada, lournal of Manufacturing Science and Engineering, Vol. 131 / 014501-1,2009.
[4] .Ibrahim Zeld, Mastering CAD/CAM, Northeastern University, MC Graw- Hill donation, 2005.
[5]. AthulanVijayaraghavan , Aaron M.Hoover,Jeffrey Hartnett,David A.Dornfeld; Improving end mitling surface finish by workplece rotation and adaptive toolpath spacing, International Journal of Machine Tools St Manufecture 49, p89 - p98,2009.
T^PCHlCOKHlVlfTNAM • SA 6 (Thing 6 nim 2013)
