SCIENCETECHNOLOGYl
XAY DI/NG MO-DUN H 5 TR0TINH TOAN VA THIET KE DO GA GIA CONG CO KHI
DEVELOPING A SUPPORT MODULE FOR MECHANICAL JIG AND FIXTURE CALCULATION AND DESIGN
Phung Xuan Lan, Dao Ngoc Hoanh
Tomtit
Thiet kequy trinh cong nghe gia cong CO khi va do gala mgt cong v i k ton kha nhieu t h ^ gian va cdng siJc cQangirdiky sir CO Mif.XuSt phat tir nhu cau thirc tien la phai giam thcri gian va nang cao hieu qua thiet ke, mot mo-dun ho trcf tfnh to^n v l thilt ke do g^ gia cong co khf du'dc xiy difng. Md-dun thu vi^n gom ba phan chinh: phan ho tro ve bao gom cac tha vien chi tiet va ket cau do ga, phan ho trd tinh toan sai so die tao d6giva phan tra cutig6m cac tai lieu ho tro thi^tke.V^si/tro giiip cda mo-dun nay, ngUcFikysif kha linh hoat trong t h i ^ k l v l tang hieu qua thiet ke ve d thcfi gian va chat lu'ong.
Tir khiia: f)d ga gia cong, Thif vien ho trO, AutoCAD
Abstract
Mechanical process planning, jig and fixtures design consume quite a lot of time and effort of the mechanical engineers. Meeting the practicalneedsforredudngthe time and improving ttie efficient of the design, a support module of mechanical jig and fixture calculation and design is constructed. The library module consists of two main parts: the support drawing part including a library jig parts and blocks, tiie support calculation induding jig and fixture machining error Glculation, the support documents for designing. With the help of this module, the engineer is quite flexible in design and inaease design efficiency in terms of time and quality
Keywords: Jig and fixtures. Support library, AutoCAD
ThS. Phijng XuSn Lan -Dal hoc Bkh khoa Ha Noi ThS. Ola Ngoc Holnh - f)ai hoc Cfing nghiep Ha Noi Email: lan.ptiungxuan^usLedu.vn
I . O A T V A N D ^
Mdt nhiem vu quan trong cua ky sU cdng nghe che tao may la thiet ke quy trinh c6ng nghe gia cong cac chi tiet CO khi. Trong do, cong viec thiet ke sod(5 nguyen cong va 66 ga chiem kha nhi^u th6i gian. Ng^y nay, nhd co sii trd giup cua phan mem AutoCAD - mot phan m^m ho tro thiet ke da nganh - ngirdi ky sir c6 t h ^ rut n g i n thcfi gian d i n h cho c6ng vi^c thiet ke.Tuy nhien, do sa phirc tap vci da dang cua cdc ket
Ng^y nhan bai: 19/6/2014 Ngay diap nhan dang: 20/8/2014
cau do ga, cong viec nay van mat kha nhieu thcfi gian, dac biet la khi chaa CO sU chuan hoa ve kich thu6c cua cac ket cau do ga. Xuat phat tCf nhu cau thiic tien do, mpt modun phan mem tha vien ket cau do ga bSng ngon ngCr lap trinh AutoLISP va Visual Basic tich hop trong AutoCAD (V6A) da daoc xay dang. Tha vien h o t r o t i n h toan va thiet ke do ga gia cong ca khi daoc xay diing vdi ba phan chfnh: (a) phan ho tro ve, thiet ke bao gom: (al) thu vien chi tiet
do ga chuan hoa nha phien ty, chot ty, khoiV, bac dan hadng, (a2) tha vien ket cau do ga nha ca cau phan do, chot ty phu, than do ga, (a3) tha vien dung cu cat; (b) phan tinh toan tap trung vao xac dinh sai so che tao do ga bao gom sai so chuan, sai sd kep chat va sai so mon cho mot so trUdng hop pho bien;
(c) phan t h u vien tra ctru bao gdm cac tieu chuan Viet Nam {TCVN} va cac so tay ve may, dao, do ga. Vdi sii trO giup cua mo-dun nay, ngadi ky sa co the giam dang ke thdi gian thiet ke trong khi van dam bao daoc chat laong thiet ke.
2. D 6 | Tt/dNG VA PHUONG P H A P NGHIEN CCrU
£)6 ga chiem mot ty le rat Idn trong trang bj cong nghe va Itnh hadng nhieu den qua trinh san xuat. Trong san xuat loat ldn, moi chi tiet gia cong trung binh can cd 10 do ga. Gia thanh che tao chung chiem 15-20% gia thanh cua thiet bi [1 ]. Vi vay, cdng viec thiet ke do ga chiem vai tro het sLfc quan trong trong san xuat. Ngadi ta cd the chia ra ba loai do ga la dd ga gia cong, do ga kiem tra va do ga lap rap, trong do do ga gia cong chiem ty le sir dung nhieu hon ca. Do do, muc dich xay diing md- dun nay chi tap trung vao dd ga gia cong.
De thiet ke dUpc nguyen cdng va do ga gia cong co khi, ngoai nhOng kien thirc tong hop ve gia cong co khi.
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Hinhl So do thu vien ho trove do ga ngadi ky sa con can cac so tay tra curu may, dao va ket cau do ga dong thdi cac kien thirc ve tfnh toan thiet ke do ga. Dd la nhQng npi dung co ban tich hpp trong md-dun va dapc md ta cy the nha sau:
a) Thu vien ho trg ve do gd 0 6 ga gia cdng co ban bao gom cac CO cau dinh vi, co cau dan haOng, co cau so dao va co cau kep chat. Ngoai ra, trong mdt sd trudng hop cdn can cd cac CO cau phu khac nha cac co cau tang dp cirng vCrng, co cau phan do...
Cac CO cau do dapc lua chon va lap tren than do ga thanh mot do ga gia cdng hoan chinh. Hinh t the hien toan
[2]. Toan bp kich thudc quy chuan oia chi tiet do ga dapc nhap vao co sfi dii lieu thiet lap trong Microsoft Excel -mot chuong trinh soan thao thong dung. Rle dU lieu excel nay se dupc doi sang duoi .*csv va la dCr lieu dau vao cua chuang trinh ve. Tuy nhien, khong ph^i lucnki ngudi kysacung liia chpn duoc cac ch tiet do ga cd kich thudc quy chuan de sCi' dung, doi khi hp ph^i che tao ra mot chi tiet do ga khac cho phu hpp. Chlnti vi the, ngoai kich thudc tieu chuan duac xay dung s i n trong cO sd du' lieu, hpco the t u nhap bp thdng so cac kich thUifc khi do chi tiet cung van t u dpng du'ocve ra theo cac kich thUdc dd.
Hinh 2. Ket cau phien ty cd lanh nghieng Bang 1. Thong so hinh hpc cQa phien tj co rSili nghieng
bp thu vien ho trp ve dupc xay diing trong md-dun. Vdi thUvien nay, ngadi sir dung se nhanh chong chen cac cO cau do ga vao ban ve de xay diing sO do nguyen cong hay do ga va de dang hieu chinh neu can. No bao gom ba thU vien CO ban la t h u vien chi tiet do ga, tha vien ket cau do ga va thU vien dao mang tinh chat bieu dien.
Trongthavienchitietd6ga,tatcacac chi tiet deu dupc lap trinh ve theo tham sd. DU lieu thdng so hinh hpc cua cac chi tiet do ga dUpc lay theo tieu chuan COST Hinh 2 va bang 1 la hinh ve va thdng sd hinh hpc cua phien ty cd ranh nghieng theo tieu chuan GOST4743-68
Trong thU vien ket cau dd ga, vi mft ket cau do ga co rat nhieu cac chi tiS do ga nen ket cau dUpc chen dUcrt dfflig khoi ma khong lap trinh theothaniisi Tuy nhien, ngudi sir dung cd the thay ddi ty le, quay ket cau sao cho phu hdp trade khi chen. Vdl ca hai thuvi^
ngudi sir dung cd the xda, hieu chinh tCfng dudng net cua chi tiet hay ketdu sau khi chen. Oe thiet ke so dd ngu)*' cdng, ngudi ky su ph^i md t i dung w cat tren tUng nguyen cong, do vay mft
3 6 TapdiiKHOAHOC&CONGNGHE. S o 2 3 . 2 0 1 4
SCIENCETECHNOLOGYl
Hinh 3. Ket cau mo-dun tinh toan sai so chuan thUvien dung cu cat vdi nhieu loai khac nhau t u dao tien, dao phay, mui khoan den da mai cung dUOc xay dUng va tich hpp vao md-dun. Toan bd thu vien hd trp ve do ga nay dUpc lap trinh dung ngdn ngd lap trinh AutoLISP [4]. Vdi mdi chi tiet trong thu vien chi tiet dd ga, ta ph^i thiet lap hai file la file thiet ke giao dien (*.dcl) va file lap trinh ve (*.lsp).Vdi moi chi tiet trong thUvien ket cau do ga hay dung cu cit, ta phai cung phai thiet lap file giao dien chen (*.dcl). Menu hinh
^nh duoc xay dUng cho phep quan ly cac ket cau dd ga (*.sld) dudi dang cac thavien(*.slb)(hinh7).
b) ThUvien tra edu
De thiet ke daoc nguyen cdng hay dd ga, ngudi ky sU phai sir dung rat nhieu loai so tay de tra cUu may, dao, do ga hay che do cat... Vdi muc dich
\hm giSm bcrt viec sir dung nhieu loai sd tay trong qua trinh thiet ke, md-dun nay cd tich hpp them nhdng tra cUu CO bSn ve may, dao va che dp cat [2].
Ngoii ra, trong mo-dun cung cd mot sd TCVN vecd khi giiip cho ngudi sir dung CO the tra ciru. Tat ca cac dCf lieu nay dupc hieu chinh va chuyen doi thuan tien cho vl^c tra cUu.
c) M6-dun tinh todn
Mpt trong nhang tinh toan quan trpng khi thiet ke do ga la tinh toan sai sd che tao do ga trong dd cd ttnh toan sai sd chuan. sai sd kep chat, sai so mdn... Sai sdchetaodogagtacdngcO khi [1 ] tinh nhusau:
[^J = ^{^^jf - ( £ " + £ ( ' +e;, +s,; ) (1) Trong do-
[E.J - sai so che tao do ga cho phep [£ ] - sai so ga dat dd ga cho phep e -sai so chuan
£^ - sai sd kep chat
£ -sai sd mdn doga E^^ - sai so dieu chfnh do ga M6-dun tfnh toan cho phep tinh toan va xac djnh tat ca cac sai so thanh phan trong cdng thirc tinh sai so che tao do ga. Hinh 3 the hien ket cau ciia mo-dun tinh toan sai so chuan tUOng Ung vdi mdt sd so do dinh vi ca ban.
Sai so chuan cua cac kfch thudc tuong irng trong moisododinh vidUpc xac dinh theo phuong phap cue dai, cue tieu [3]. Cong thirc (2) va (3) la sai sd chuan tinh cho kich thudc HI va H2 vdi sodo dinh vi chi tiet tren khdi V khi phay mat phang nam ngang (hinh 4).
1 a sin —
2 1 sin — . 2
:
+1
Trong do:
a-goc khoi V
T - dung sai cua dudng kfnh tru Mat gia cong.
Hinh 4 So do dinh vi chi tiet tren khoi V
Sai so kep chat phu thudc vao gdc hpp bdi phUdng life kep va phuong dich chuyen ciia chuan gdc, loai cd cau dinh vi, vat lieu gia cdng, liic kep va kfch thudc CO ban ciia cd cau dinh vi.
Vi du khi vat lieu gia cdng la thep, dinh vi tren chot ty chom cau thi cong thdc tinh sai so kep chat nha sau [1]:
6.23,.
,b/ -U,UUJIiB -i Trong dd:
Oj - gdc hop bdi phaong kfch thudc thuc hfen va phuong djch chuyen ciia chuan gdc
HB - dp cdng cua vat lieu theo Brinel (kG/mm^}
R - ban kfnh chdm cau (mm) W-IUckep(kG)
Sai so mon dUpc xac dinh theo [1]
cdng thirc
s^ = P,v'^ (5) Trong do:
N - sd luong chi tiet duc^c ga dat tren do ga
3i -he so phu thuoc vao CO cau dinh vi va dieu kien tiep xiic.
M6-dun tinh toan dupc lap trinh bang ngon ngCr VBA tich hop trong AutoCAD [5]. Khi lap trinh VBA, ta phai thiet ke giao dien va lap trinh xir ly cac sU kien trong form C.frm) va lap trinh module (*.bas) gdm cac ham tinh toan.
3.KETQUAVAPHANTiCH Toan bp md-dun tinh toan va thiet ke daocgdi gpn trong mptfile cai datCNCTM.
exe Sau khi chay file cai dat CNCTM.exe, trong phan mem AutoCAD co them mpt menu CNCTM va ba thanh cong cu la co cau dinh vi, ca cau dan hadng, so dao, kep va tha vien ket ca'u doga (hinh 5). Khi ngadi su'dung kfch chpn mot bieu tuong tren menu hay thanh cdng cu, hop thoai laa chpn se hien yeu cau ngUdi sif dung nhap da lieu nhu diem chen, kich thudc CO ban (hinh 6), 6 day, ngudi sir dung cd the Ilia chpn chi tiet chuan hay chi tiet tu tao.
Giao dien trong thu vien ket cau do ga va dung cy cat duoc the hien tren
S623.2014-TapdiiKHOAHOC&CONGNGHE 3>
CONG NGHE
Hinh 5 Giao dien menu va thanh cong cu
Hinh 7 Giao dien thit vien ket cau do ga
h i n h 7. N g u d i sii d u n g c h i v i e c c h p n k e t c a u d o g a m o n g m u o n d e c h e n v a o b a n v e t h i e t k e sau d o h i e u c h f n h n e u c a n .
T r o n g p h a n t i n h t o a n , n g U d i sir d u n g c d t h e l u a c h o n e a c h t h d c t f n h t o a n rieng c h o t i m g sai so t h a n h p h a n h o a c c h p n e a c h t h i r c t d n g h o p t f n h t o a n sai so c h e t a o d o g a v d i e h d c n a n g t h a m c h i e u ra cac sai so t h a n h p h a n ( h i n h 8).
N g o a i ra, m d - d u n nay c u n g d u o c xay d u n g v d i m u c d i c h t a o ra s u t h a n t h i e n v d i n g u d l sir d y n g . D o d o , b e n c a n h m e n u h a y t h a n h c d n g c y d e g o i l e n h , n g u d l sir d u n g c d t h e sir d u n g c a u l e n h A u t o C A D d e g o ! m o t l e n h ve. B a n g 2 la t r i c h d a n m d t so l e n h m d i t a o l a p t r o n g A u t o C A D t r e n t o n g sd g a n 100 l e n h m d i .
-H ^
Hmh 8 Giao dien tinh toan sai so che tao do ga va tham chieu giao dien tmh toan sai so mon
Bang 2. Danh muc lenh trong menu CNCTM LOAI
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Vdi s u t r o g i i i p cua m d - d u n t i n h t o a n va t h i e t ke d o g a nay, cac d o g a g i a c d n g CO k h i d e d a n g va n h a n h c h d n g dUOc x a y d u n g . H i n h 9 la k e t q u a t h i e t ke d o g a c i i a n g u y e n c d n g p h a y m a t d a y c h i t i e t g d i d d ( b i e u d i e n b S n g n e t _.._.,_ t r e n h i n h ) n h d s i i h d t r a d a n g k e c i i a m d - d u n , T r o n g d d t o a n b p cac c h i t i e t c i i a d o g a n h u t h a n d o g a , c h o t ty, c a s o d a o , t h e n d a n h u d n g d e u d u p c lay t d t h u v i e n h o t r p v e d o g a . P h a n t i n h t o a n t h e h i e n k h a h i e u q u a k h i xac d m h sai sd c h e t a o d d g a . Gia sir lay d a lieu b a n d a u n h u sau: (a) k i c h t h u d c g i a c d n g c a n d a t la 2 0 ± 0 , 0 4 m m ; (b) so l u o n g c h i t i e t d u o c g a d a t t r e n d o g a la 1 0 0 0 c h i e c ; (c) c h o t t y c h e t a o t U v a t lieu t h e p 4 5 . TU m d - d u n t i n h t o a n , t a xac d i n h sai so m o n la 0,016 m m , sai s d d i e u c h i n h la 0,01 m m , sai sd c h u a n v a sai sd k e p c h a t la 0. O o d d k e t q u a t i n h t o a n sai so c h e t a o d o g a c h o p h e p la 0 , 0 1 9 m m .
4 . K ^ T L U A N
Hinh 9, So do nguyen cong phay mat day dHBet goido^
Bai b a o d a t r i n h b a y m p t m o - d u n h6 t r d t f n h t o a n v a t h i e t k e d o g a tich hop t r o n g A u t o C A D . M d - d u n d a xay dilrtg d a p c t h U v i e n k e t c a u d o ga, cac tai lieu tra c u d v a m p t s o t i n h t o a n c o b a n d e phuc v u c h o c d n g viec t h i e t k e n g u y d n cong v a d o g a g i a c d n g c d k h i . M 6 - d u n phan m e m h o a t d d n g k h a h i e u q u a vdi nhilu Uu d i e m n o i b a t (a) q u a t r i n h cai dat dfln g i a n , g i a o d i e n t h a n t h i e n ; (b) c a sdf dC lieu p h o n g p h u ; {c) t h U v i e n d o n g ; (d)tinh t o a n va t h i e t ke n h a n h c h d n g ; (e) tuwtg t h i c h v d l n h i e u p h i e n b a n A u t o C A D k h k n h a u . M 6 - d u n d a d a p c n h i e u sinh vlen SIS' d u n g rat h U u d u n g t r o n g q u a trinh 13m d o a n m d n h o c v a t o t n g h i e p n g a n h cong n g h e c h e t a o m a y . N d c u n g se la cong cu d a c lUc t r p g i i i p c h o cac k y s u c o khi trong q u a t r i n h t h i e t ke, q u a d d c h o phep nil n g a n d a n g k e t h d i g i a n v e v a t i n h toan 36 g a t r o n g k h i v a n d S m b a o t f n h chfnh xic v a c h u a n h d a t r o n g t h i e t ke. Trong tlWng lai, m d t so p h a n t f n h t o a n can duWc bfi s u n g t h e m d e n a n g c a o t i n h nang tinh t o a n c i i a m d - d u n
Phan bien khoa h o t : TS. Pham ViinfliM
TAI Ll£U THAM K H A O
dl.GS.TS.TranVan Dich, Doga, NXB KHiaZDOt [2j GS.TS Nguyen Oac Lgc, So tay Cong nghe CM taomay,t3p1,2,3,NX6KHKT,200S.
|31.GS.TS.TranVant)ich, Cong nghe che tao mir.
NXB KHKT. 2003.
14], TS. Nguyen HQti loc, Ngon ngfl lap tiWi AutoLisp,Tap 1,2, NXB TP.HCM, 20O1.
[5| Marion Cottmgham, Master AutoCAD VBA- Sybex,2001.
3 8 TapchiKHOAHOC&CONGNGHE- So 2 3 . 2 0 1 4
