NGHIEN CUfU-TRAO D 6 |
NGHIEN CU'U THIET KE MAY TAG M A U KIM LOAI T A M SLT DUNG CONG NGHE BI^N DANG CUC BO LIEN TUC ISF
DESIGN OF SHEET METAL PROTOTYPING MACHINE USING INCREMENTAL SHEET FORMING (ISF) TECHNOLOGY
Phan Dinh Huan\ Le Khinh Dien', Phan Dinh TuanS Nguyen Thien Binh^ Nguyin Thanh Nam^
'Khoa C P khi, TrUdng Dai hpe Bach khoa TR HCM
^PTN Dieu khien sd va Ky thuat He thong DCSELAB, VNU - HCM.
Bdi bdo trinh bdy mgt thie't ke mdy tgo mdu sd dung cong nghe bien dgng cue bg lien tue (ISF).
Thiet ke cd khi khi cita mdy co nhdng diem khac biet so vdi mot mdy phay CNC truyen thong. Do cdng vdngdUdc tdng cUdng cho true chinh mdy de co the ddp dnglUc dgc true vdi gid tri ldn khi gia cong bang cong nghe ISF. Mdy dUdc che tgo thdnh cong vd hogt dgng on dinh khi gia cdng bien dgng tdm thep CT3 vudng 210 mm vd be ddy tdm 1 mm. Dieu ndy cho thdy thiet ke cd khi vd dieu khien cua mdy ddp dng tot, CO the dp dung degia cdng cdc mdu tdm phuc vu cho cdc ngdnh cong nghiep hien tgi.
Tfl khoa: Incremental Sheet Forming (ISF), Die-less NC forming machine, SPIF...
This paper present a design of prototyping machine using for incremental sheet forming (ISF) technology. Mechanical design of this machine has specified feature in compared with a traditional CNC machine. Stability of spindle is considered to apply high value of axial force when forming sheet metal by ISF technology. Machine is manufactured and working properly when forming 1 mm - CT3 sheet steel 210 mm square size. This proves that mechanical and control design of the machine is capable of require- ments and can be applied on forming sheet metal using for current industrial fields.
Key words: Incremental Sheet Forming (ISF), Die-less NC forming machine, SPIF...
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NGHIEN CUfU-TRAO D O I
l . G I O i I T H l £ u
Trong nhflng nam g i n diy, cic phUPng phap tao mau nhanh da phat trien manh me. Cac phflong p h i p nay ngay cing tdt e i v i dp ehinh xac, dp phfle tap cua ehi tiet v i thdi gian tao mau ngiy cang ngan hfln. Ben canh sfl tien bp cua cac phflpng phap tao mau nhanh truyen thong, cac phflpng p h i p tao mau nhanh mdi eung dflpc nghiin cflu phat trien. Cdng n g h i bien dang cue b0 liin tue (ISF) l i mpt trong nhflng phflong p h i p mdi cd nhieu tiem nang trong Unh vflc n i y [ 1 ].
Trong eong n g h i ISF, mot dung cu tao hinh dau b i n cau dflpc dieu khii'n bdi may gia cong CNC bing chflpng trinh GCODE lap trfldc va theo do tam kim Ioai s i dflpc bien dang d i n din. Bang each bien dang tao hinh tam kim loai theo tflng vi tri tiep xue tai dau dung cu (bien dang cue bp) m i eong nghi ISF cd the tao bien dang Idn hpn tren cung mot vat lieu so vdi eic phflpng p h i p tao hinh kim loai tam khie [2].
Cie sin pham ed the i p dung edng nghe ISF rat da dang v i khong can dung khudn hoae do gi phflc tap. Hinh dang dflpc tao binb cung ed the thay doi linh boat bang each thay doi trflc tiep tfl md hinh CAD m i kliong phii di qua giai doan gia cong lai bp khudn. Do do, phflong p h i p ISF rut ngan thdi gian den thj trfldng cua sin pham va cung giim gia thanh eho nghiin cflu va thay ddi thiet ke ban dau. [3]
xie cua m i y CNC va sU eflng vflng ddi vdi true ehinh gifl dung eu tao hinh theo phUPng dpc true.
2. C O sd TfNH TOAN WC CHO MAY ISF Trong q u i trinh thiet ke miy tao mau ISF, can phai tim bie'u vi co che bien dang kim loai bing cdng n g h i ISF va xac dinh gii tri eae lUe t i c diing len dau dung eu. Trong thiit k i may, ta thiit lap mo hinh tinh Iflc trin dau dung eu tao hinh nhfl sau:
Hinh L Mo hinh sd dung tinh todn lUc cho mdy ISF.
cii:^ - -de, > O dt:,, -. Cl dt:, <= O
cr ^ cr — ~
Cong nghi biin dang cue bp lien tue ISF "
phit trien nhanh cung vdi sfl phit trii'n cac miy CNC hien dai. Nhflng ngfldi ta nhanh chdng nhin Trong dd:
ra eic miy gia cong CNC hiin tai ehi thieh hpp cho qua trinh cat gpt kim loai ma trong do lflc cit gpt trin dung eu cat theo phflpng ngang ldn hpn phflpng dpe true. Trong khi dd, ddi vdi cong nghi ISF thi Iflc bien dang tie dung theo phflong ngang Iai nhd bon so vdi Ifle dpc true [4].
—
a/2 - c r , .
2 ( D - 2 / )
D.cr, n -h l.t -Iter, D-k-ll
CTy
<
Do dd, can thiet phai nghien cflu che tao mpt thiet bi diiu kbii'n sd thieh hpp cho gia eong ISF Thiet bi niy can co sfl kit hpp gifla sfl chinh
- 0|, o^, o, la 3 thanh phin flng suat ehinh.
- a=a^ tao phin lflc nen F^ lin b i mat eau eua dung cu tao hinh. Ap lflc F^ tao ra Iflc ma sit F,, v d i / i a he sd ma sat gifla dung cu tao hinh vi tam (hinh 1).
- Og tao lflc vdng F|, n i m trong mat phang ngang, cflng chieu vdi thanh phan ma sit F^ vfla phin tich d trin.
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NGHIEN CUfU-TRAO D O I
- 0 tao Iflc cang tiep tuyen F^ lin be mat dung cu tao hinh.
- 1 la be day tam.
- r^^^^ l i ban kinh dung cii tao hinh r^^^=D/2.
- Oy l i flng suit ehay cua vat lieu tam.
Bing cac tinh toin so hpe, ta dfla ra gii tri lflc tie dung theo eic phUPng x, y, z nhU sau:
F.(e) = TT ^ '^' (Dsin' a + 2t(\ - cos' a)
^^ ^ 3(D + 2/)
Fy{0) = K ^ •^' ( D ^ - ^ ~ ' ^ + f ( / + l) s i n ' a
"^ 2{D + 2.t) 2 r = ; r - ^ - ^ ^ ( 2 / + 2 / + D )
^ 6(D + 2.0
Xiy dUng do thi bieu diin moi quan h i gifla lUe tie dung vdi gdc tao hinh theo phflpng x eho trfldng hpp tai Idn nhat:
- Dudng kinh dung eu D=20mm.
- Lfng suit chay eua vat lieu tam o =215x10^
Pa (Inox 304).
- Chieu day tam gia eong t = l m m . - Gde bien dang tao hinh trin tam a.
- Gdc gia cong theo phUPng ngang 9=0 (ehay dung eu theo phUPng x).
- H i so ma sat gifla tam va dung cu tao hinh f= 0.05.
Do thi cho ta thay gia tri ldn n h i t cua life tao hinh theo phUPng x la 2000N. Mot eieh tflong tfl cd the xac dinh gia tri cua lflc tao hinh theo phUPng y v i z la 2.000N va 4.500N.
3. TINH TOAN THIET KE 3.1. Tmh toan thiet ke khung may
Khung m i y la mot yeu to quan trpng doi vdi dp on dinh cua miy. Cac may CNC thong thudng cd ket eau dau true ehinh c6ng-x6n v i ban m i y di ehuyen theo hai phUPng x-y. Tuy nhiin, ket cau n i y thich hpp vdi eat gpt kim loai hon la bien dang ISF vi lUe dpc true eua phUPng phap cat gpt ldn. Trong trUdng hpp bai bao dUa ra mpt so lita chpn phflong an khung may dfla vao dac diem di chuyen cua ban may nhfl sau:
Bdng 1. Bdngltia chgn cdcphUdngdn.
PhUcfng an
dinh (roboi cong nghiep) Ban may di chuyen theo 2 phuong (may CNC iruyen thong) Ban may di chuyen theo 1 phuong
DSp dng lue
x
V
V
Dp cdng
"
V
Do
^
V
V
C o don gian
^
V
^
Mde do hnh
V x
X Hinh
V V
V F<(N)
" " a (do) ' Gid tri tUc biin dang theo phUdngx.
Dfla theo eic d i n h gia phflpng i n da dflpc trinh bay, phflpng an ban may di chuyen theo m^t phflpng Ii phflpng an ed nhieu flu the nhat, co day du eic yeu to quan trpng cd the dap flng dflpc kha n i n g tao hinh ebb eong nghe ISF nhfl kha n i n g d i p flng lUe biin dang theo phUpng thang ddng (dpe true z), dp cflng vflng vdi cP cau ci^m true z di ehuyen tren cau true t r i n h dflPc dang cong xdn v i do do cung d i p flng tot v i k h i nang gia cong chinh xic. Phflpng i n n i y dflpc trinh biy dfldi dang sP do nhfl sau:
TAP CHf CO KHf VIET NAM • S6 1+2 (Thing 1+2 nam 2013)
NGHIEN CUfU - TRAO DpI
Hinh 3. PhUdng dn khung mdy lUa chon.
Dfla trin cP sd phflpng i n lfla ehpn, tien hanh thiet ke sp dd dpng eho miy:
<5«t
Hinh 4. Sd dd dgng mdy tgo mdu ISF.
3.2. Tinh toan thiet ke ket cau true chinh Trpc chinh m i y l i mpt bp phan rat quan trpng vi nd quyet dinh dp ehinh xac va cflng vflng khi gia eong. Thiet ke ket cau true ehinh dflpc tinh toin dfla trin cac thdng so ve lflc bien dang d i tinh toan d eic phan trfldc. Trong do, die biet chu trpng h^ thong 6 bi chiu lflc giup nang cao kha nang bien dang t i m theo phflpng dpc true.
Dau eon BT50 dflpc dd dpc true bing he thdng eac 6 bi dd chin dflpc sap xep theo hai chieu chiu Iflc doi nhau de cd the chiu dflpc lflc dpe true theo hai hfldng eua phflong thing dflng khi gia cong bang cong nghe ISE De d i m bao tmh dn dinh trong chuyin dpng quay cua dau true ehinh, mpt he thong hai 6 bi dd eung dflpc thiet ke d dau phia t r i n cua ong bao con.
4. MO HINH HOA VA M O PHONG Sau eac tinh toin chi tiet eho ket eau miy, nhdm nghiin cflu tien hanh md hinh hoa tren cac phan mem 3D va Idem ehflng lai flng suit bing phflong p h i p FEM. Mo hinh miy dflpc ve t r i n phan m i m thiet ke Inventor nhfl sau:
Hinh 6. Mo hinh mdy ISF da mo hinh hod.
Dfla tren mo hinh da thiet ke, nhdm thiit k i kiim ehflng cic ket qua tinh toan bing phflpng phip FEM.
Mo phong tren mo hinh dflpc thflc hien vdi lUc 2.000N theo phuong x-y va 4.SOON theo phUPng true z dupe dat vio dung eu tao hinh.
Cic thong so ve vat lieu dUpe lay theo vat lieu tfnh toan. Kit qui l i cie chuyen vi vi Ung suat trin md hinh dat eac tiiu chuan bin cua thiet ke miy. Cu t h i ehuyen vi ldn nhat v i flng suat Idn nhat Ian lupt l i 2,203x10-' mm vi 16,59 MPa.
Hmh 5. Kit cdu hi thdng 6 bi dgc true.
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NGHIEN cflu-TRAODpi
hinh hoc hay khong; Kiem tra kich thacic diidng kinh ngoai dai dien cho cac kich thadc 16. Kiem tra kich t h a 6 c diidng kinh trong dai dien cho kich thildc true.
I I — ' •—'"!
Hinh 9. Bdn ve chi tiet hinh vdnh khdn.
Htnh 7. Ket qud mo phong cho dng sudt vd chuyen vi (dudi).
5. CHE TAO VA CHAY THLf NGHIEM De thfl nghiim khi nang gia cong va noi suy chinh xae eac biin dang hinh hpe eung nhU xie dinh dp chlnh xie gia cong thUc te tren san pham, nhdm nghiin cflu quyet dinh chpn gia cong mpt ehi tiet dPn gian nhflng ed diy du eac yeu td cho cac thfl nghiim tren, do la hinh v i n h khan.
Sau khi thflc h i i n gia cong chi tiet, kit qua dat dflpc dung theo y i u eau. Cu t h i nhfl sau:
+ Dudng kinh trong: 30.06 mm (A=30- 29.96 = 0.04<0.05).
-I- DUdng kinh ngoii: 69.97 mm (A=70- 69.97 = 0.03<0.05).
+ Dp khong tron A=0.02 mm.
Hinh 10. Sdn phdm gia cong vd kie'm tra kich thUdc.
Hinh 8. Mdy ISF sau klu che Igo vd tdp rdp.
Ngoii ra, m i y cung thfle nghiem gia edng Cac yeu to trin hinh v i n h khan: Npi suy ISF mpt hinh con thang t r i n vit lieu tam thep mpt dudng trdn, bao gdm cie dfldng kinh trong CT3 day 1 mm vdi dp eflng Idn so vdi cie vat lieu vi dfldng kinh ngoai. Kiem tra bien dang hinh tam khic. Dieu n i y ehflng to kha n i n g chiu lflc hpe eua san pham gia cong ed sai so gay bien dang dpe true Idn cua m i y d i p flng cong nghe ISF.
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NGHIEN Cflu - TRAO DPi
Hinh ll, Sdnphdm thd nghiem gia cong ISF tdm thep CT3 ddy 1mm.
6. KET LUAN
Cong nghi bien dang cue bp lien tue Ii mot eong nghe day tiin nang. Cac thiet ke may va thiet bi ehuyen dung eho qua trinh ISF si day manh sfl phat trii'n cua eong nghe.
Miy tao mau kim ioai bang eong nghe ISF da dupe ehe tao thanh cong. Cae thfl nghiem da eho thay kha nang gia eong v i dp ehinh xae dat dflpc phu hpp vdi cong nghi ISE May tao m i u ISF cung dflpc thiet ke vdi mue dieh dong gdp mpt phan vao viee phat trii'n cong nghi ISF tai Viet Nam ca ve mang thiet bi va cong nghe. •>
Ngay nhan bai: 05/01/2013 Ngay phan bien: 01/02/2013
Ngfldi phin biin: PGS, TS. Pham Ngpe Tuan, Chu nhiem Bp mon Cbe tao may,
Trudng Dai hoc Bach khoa TP HCM.
Tai liiu tham khao:
[1]. Meehs Pohlak (2007). Rapid Prototyping of Sheet Metal Components with Incremental Sheet Forming Technology.
[2]. J.Jeswiet, E Micari, G. Hirt, A. Bramley,). Duflou, J. Allwood . Asymmetric Single Point Incremental Forming of Sheet Metal, Ann CIRP Annals, 54, 2005, 623-649.
[3]. RA.F. Martins, N. Bay, M. Skjoedt, M.B. Silva, Theory of single point incremental forming, CIRP Annals - Manufacturing Technology 57 (2008) 247-252
[4]. J.M.Allwood, N.E.Houghton, K.P.Jackson; Hie Design of an Incremental Sheet Forming Machine; University of Cambridge - United Kingdom.
TAP CHI CO KHI VIET NAM So 1+2 (Thing 1+2 nam 2013)
