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Design and Manufacture of Dies and Molds
Keynote Paper
Design and Manufacture of Dies and Molds Taylan Altan (1). The Ohio State University/USA
summary. The t e c h n o l o g y o f d e s i g n i n g a n d m a n u f a c t u r i n g d i e s a n d m o l d s i s i n c r e a s i n g l y based o n t h e a p p l i c a t i o n of Com pute r Aide d D e s i g n a n d H a n u f a c t u r i n g (CADICAN), i . e . t r u e 3D c o m p u t e r g r a p h i c s , a n d Com put e r N u m e r i c a l C o n t r o l (CNC) m a c h i n i n g . The u s e o f CADICAM r e d u c e s lead t i m e a n d i m p r o v e s communication between d e s i g n a n d m a n u f a c t u r i n g a c t i v i t i e s , a s w e l l as q u a l i t y and r e p r o d u c i b i l i t y . Co;:::mter A i de d E n g i n e e r i n g (CAE) u s e s v a r i o u s a n a l y s i s t e c h n i q u e s t o s i m u l a t e m a t e r i a l f l o w t o p r e d i c t and a v o i d d e f e c t s and improve die d e s i g n . T h i s p a p e r h a s been p r e p a r e d w i t h i n p u t from v a r i o u s CIRP c o l l e a g u e s a n d r e v i e w s t h e a p p l i c a t i o n of CADICMICAE i n m e t a l f o r m i n g , a n d d i s c u s s e s t h e s t a t u s o f advanced computer a p p l i c a t i o n s s u c h a s E x p e r t Systems and p r o c e s s modeling t e c h n i q u e s K E Y NOHDS:
D i e m a n u f a c t u r i n g , CADlCAMlCAE,
p r o c e s s modeling, metal f l o w simulation, e x p e r t systems
i n forming
i.
IhTRLLhCTi(lw
macninins, y r i n o l n q a n a a s s e m o l y , most a i s c r e t e * a r t s m u s t f i r s t oe n l a n u t a c t u r e d to n e a r finish o i m e n s i o n s v i a o n e ot t h e " n e t or n e a r - n e t " shaping processts: ( a ) aelt processing (castin$, i n - ~ e c t i o n n o i ~ i n y ) , ( b ) s h a k i n g from powder , (c) f o r m i n q f r o a s n e e t , dnd ( c i ) form inc , trom b i l l e t . in ail t h e s e p r o c e s s e s , g e o m e t r y is t n e common t h r e a d a n d t h e t e c h n o l o g y ot dre/nola d e s i g n a n d manutact u r i n i , is a most s i g n i r i c s n t c o n s i d e r a t i o n . Z K ~ O Kto
In a
n e t s h a p e m a n u t d c t u r i n g F r o c e s s , d i e s are u s e d t r a n s f o r m a p i v e n material, u s u a l l y s n a p e l r s s OK a simple cjeometry, i n t o d u s e t u l ?art. The r e s u A t i n s part n a s d c o n p l t x geometry w i t h weilG e i i n e d s h a p t , s i z e , t o l e r a n c e s , a k p e a r a n c e and pro3ertit.s [ A i t h n e t a l . , 19831. The d e s i r e d p a r t yeometry 1 5 storea i n d i e s a n a m olds a nd i m p a r t e d o n t o t h e . . , a t e r i a l w i t h or w i t h o u t p r e s s u r e t h r o u g h t h e oie-m.teriai interface.
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p l q s i c a i pnenomena a e s c r i o i n g a n e t s h a p e manur o c t u r i n g p r o c e s s are u l r f l c u l t t o e x p r e s s w l t h q u a n titative rerptwnsnips. T he m a t e r i a l t i o w , the c o n , e n t r u i i o n a n 6 t r i r n s z e r a J r i n 5 tr'e rrocess a n a t1.e rti-t L U I ~ I . L ~ ~" t t w e e n >KOCCSS v a r i d u i e s an0 t n e pCOclJCt 2fG>t!Ctlr5 uKf2 O l f L l C L L t t O >KecllCt. hb a e e s u - L , c . i c ~ e s i q is ~ IL,ore a n a r t trian 6 s c i e n c e . i c . e a i A b , t r r t e n 4 i n t e r i n q u e s i i n DL u i e s c o n s i s t s of: ~ l s t ~ u ~ i b i ~ ti rni ec ,a i n e n i a t i c r e i d t i o n s n i p s (shapt, v e i o i i ~ i t s , s t r a i n fates, s t r a i n s ) bttween t h e i n c o n i n q ~ i c l t e r l d lGnu t n e stla>ro p r o d u c t , i.e. preu i ~ i l r i $I.iacerlal r l o u , ( 0 ) e s t a u i l s n l n y t h e l i h i l t s of >rwLciuirici, i.e. ~ e t e r ~ l i n i n y whtthhr it is p o 5 5 ~ 0 ~ et~ ssihre t n e part u i ~ n o u c s u r r a c e or in:ernnl l o i & r t , a m ( c ) r r e u i c t i n y t h e torces a n c stresses n r c e s s e r y t o e x e c u t e tire s n a p i n q o ? e r a t i o n s o c h a t t o o i i n b -no %uipiaient c a n be d e s i g n e d a n o The
StrtLteo.
s c i e n t i f i c o e s i q n or the a l e s , i t is necessari t o corisiuer e a c n i n d i v i o u a r n e t S h a p e .i~anLracturinq a5 a s y s t e m , c o n s i s t i n $ of ( a ) 1 r . c ~ i~n. $ : , b t e r i a i anu its p r o p e r t i e s u n d e r p r o c e s s i n y ~ i e s , inchdin$ Geometry, c o n ~ i t i u n s , (t) the i i a t t r i ~ r b, u r r h c t t i n i s n , a n o t e m p e r a t b r e s , ( c ) c o w l c i m s ox i r i c i l ~ na n6 n e a t t r a n s f e r a c ;ie-iitaterial I r l L e x a c e , ic) tile l a e c n a n i c s 01 s n a p c n a n s e , ( e l t h e &,i.ir...ent ~ s e u , u i t n its v e i o c i t j , rorce, riqt6ity nno ro;rer C d p a U i A l t i e b , ( f ) t n e r ~ a nu ~ i t s pro~ ,brties, e n c ( 5 ) ti.= pl-rit environment incluainq ..u;..an eCOnG~..iL i a L C O K S .
W i t h t h e w i d e l y a c c e p t e d u s e of CAD/CAM, d i e m an u f acturing h a s been e x t e n s i v e l y computerized. The p r e s e n t t r e n d s now seem to be ( a ) i m p r o v i n g d i e d e s i g n m e t h o d s b y s i m u l a t i n g and o p t i m i z i n g v a r i o u s f o r m i n g p r o c e s s e s . and ( b ) e s t a b l i s h i n g a n i n t e g r a t e d d e s i g n a n d m a n u f a c t u r i n g a c t i v i t y a l l t h e way from c o n c e p t i o n , d e t a i l e d d e s i g n , and CNC m a c h i n i n g , and quality control. 2.
APPLICATION OF CAD/CAM
I N D I E MAKING
C o n s i d e r i n g a g i v e n metal f o r m i n g p r o c e s s a s a p o t e n t i a l net shape manufacturing oepration, t h e a p p l i c a t i o n of computers i n d e s i g n and m a n u f a c t u r i n g o f f o r m i n g d i e s is i l l u s t r a t e d i n F i g u r e 1 an d involves : t h e e l e c t r o n i c and a u t o m a t i c t r a n s f e r o f 3 D p r o d u c t g e o m e t r y and o t h e r d a t a b e t w e e n d e s i g n and manufacturing (groups, plants, Or companies), t h e c o n v e r s i o n o f t h e a s s e m b l y - r e a d y p a r t g eo m e t r y i n t o a g e c i n e t r y t h a t is ' p r o d u c i b l e " w i t h t h e process u n d e r c o n s i d e r a t i o n . t h e p r e l i m i n a r y d e s i g n of d i e s / m o l d s n e c e s s a r y t o c a r r y o u t t h e n e t shape m a n u € a c t u r i n g process, t h e s m u l a t i o n and o p t i m i z a t i o n o f e a c h p r o c e s s i n g o p e r a t i o n and t h e a s s o c i a t e d tool d e s i g n to r e d u c e p r o c e s s d e v e l o p m e n t a n d t r i a l a n d error, and m a n u f a c t u r i n g o f d i e s and m o l d s by CNC mach i n i n g or b y Electro D i s c h a r g e M a c h i n i n g (EDM) u s i n g C3C m a c h i n e d electrodes.
' L h ~ a ,LOT trie
, t is c l u i ~ e c A t - r t:.-~ tr.e c o n s i u e r a t i o n of ail net ~ i . u ~r c i . a n ~ t ~ c ~ . i . rpirnoyc e s s e s wouiu be too e x t e n s i v e L G K tr.e sco+ 01 t ~ i s paper. inereiore, tne present U L ~ C ~ S ~is~ rUi i .~t i L t r u co o i e s ariG i.ioks u s e a i n iuetai
d t i t o u b f i r.,any of t i r e . % s n u r d c t L r l n y p r i n c i p l e s a k p i y CG uies moics u s e a i n ~ t ~ . ~e rK O C ~ ~ suet. ~ C S as 4 u a e r m e t a l l u r g y forming, ~ i c&.cinq t i njf2CtlGn i, #oiuinq.
Most c o m p a n i e s who u s e CAD/CAM f o r d i e m a k i n g , u s e t h e i r s y s t e m for g e o m e t r y and d a t a t r a n s f e r , d r a f t i n g , and NC m a c h i n i n g I A l t a n , 1982, A l t a n a n d Billhardt,19831. These a p p l i c a t i o n s o f f e r immediate p r o d u c t i v i t y increases although they use only t h e d e s i g n e r ' s experience and/or empirical equations w i t h o u t much a n a l y s i s ( e x c e p t f o r c r o s s - s e c t i o n a l a r e a s a n d volume c a l c u l a t i o n s ) . Most u s e r s o f f o r d i e m a k i n g u t i l i z e o n l y a small p e r c e n ~CAD/CAM t tage of t h e c a p a b i l i t i e s a v a i l a b l e on s u c h s y s t e m s . T h i s s i t u a t i o n is l a r g e l y d u e to t w o f a c t o r s : (a) t h e systems are still s m e w h a t cumbersome f o r h a n d l i n g t r u e 3D s u r f a c e s e n c o u n t e r e d i n d i e s and m o l d s , a n d ( b ) most users d o n o t h a v e a d e q u a t e t r a i n i n g or b a c k g r o u n d i n d e s c r i p t i v e g e o m e t r y to p e r c e i v e and c o n s t r u c t c o m p l e x s u r f a c e s .
~o:,'inb
CAD/CAM s y s t e m are b e i n g u s e d t o d a y i n t h e metal f o r m i n g i n d u s t r y . These have t h e t r u e 3 D s u r f a c e , a n d i n some cases, e v e n s o l i d g e o m e t r y r e p r e s e n t a t i o n c a p a b i l i t y a s w e l l as modules f o r I~..F ~ ~ ~ s ~ i i or~ a ~l e s~ +nc t i nolcs, o n ~ i materials e p a r a m e t r i c d e s i g n , and g e n e r a t i n g NC c u t t e r p a t h s , an(r V ~ L ~ U U iqletr.ous S or C l t r. la nL ra c c ure n a v e Deen 01smany O t h e r f e a t u r e s . A l i s t o f CAD/CAM s y s t e m s most ~ u ~ e~ arA r i tcf i r . a v e r y cG,..prel.erisive y ~ ~ i i c a t i ~ n s . commonly u s e d i n the d i e a n d mold making i n d u s t r y is i L p f i = e , ,3YAl ~ r i t i i y ,d i e s nay or ciass1tiea D a S e O g i v e n i n F i g u r e 2 [ A l t a n and Oh, 1 9 8 4 1 . -11 ,L ui. e t T I C z c ~ c u r e r , s b r r a c e i ty , a p p i i c u t i o n d1.c ,..at t r i ~ b C d . . a d 4 8 ~ ni w r u L a c t u r i n s recnnlques An i m m e d i a t e and s i g n i f i c a n t q u e s t i o n f a c e d by a d i e ir.cAuuh ~ d 5 ~ i r . 5colc , O K fioc r.odoing, c02y m i l l i n 5 O K a n d mold m a k e r i n t e r e s t e d i n CAD/CAM is w h a t s y s t e m tLrTriia,, oi& t ~ t c t r o~ i s c n d r t , e . , , a c hininq ( t u i l ) a n u to p u r c h a s e . O b v i o u s l y , t h e r e is n o u n i q u e a n s w e r L1.C . . & ~ ~ i r . i i a , of GI+ c d v i t i e s o i r e c t l y K K O a ~ le sceei s i n c e c o n d i t i o n s v a r y from o n e company to a n o t h e r . o r ot LL!. e l ~ ~ t r w i s . i i r t t n a c o d ~ i r i d t i o nof t h e s e However, t h e f o l l o w i n g f a c t o r s ( n o t n e c e s s a r i l y i n ttL..r.iji.es is - ~ e ( r LOT Iianuidcturin., ales dt a order o € s i g n i f i c a n c e ) m u s t b e c o n s i d e r e d : r t c u c e i coaL rtr& w l t f i d c c e p t c r o r e L e a C t i n e s . L ~ S C U ~ n~e W re aISG
A l a r g e number o f
.
Annals of the CIRP, Vol. 36/2/1987
455
S u p p o r t and m a i n t e n a n c e f o r b o t h s o f t w a r e and h a r d w a r e m u s t be a v a i l a b l e , e s p e c l a l l y i f t h e p u r c h a s i n g company d o e s n o t h a v e e x t e n s i v e i n house computer e x p e r t i s e . T h e CAD/CAM s y s t e m m u s t be c a p a b l e O f Z D d r a f t i n g with dimensions, t o l e r a n c i n g and t e x t , a s w e l l a s 3D g e o m e t r y r e p r e s e n t a t i o n ( w i r e f r a m e and s u r f a c e ) and NC c u t t e r p a t h generation. F o r p r e d i c t i n g m a t e r i a l f l o w and t e m p e r a t u r e s a n d f o r c o n d u c t i n g s t r e s s a n a l y s i s on t h e d i e s p r o d u c t s , i t is n e c e s s a r y t o u s e t h e F i n i t e ( F E M ) or F i n i t e D i f f e r e n c e E l e m e n t Method Method (FDM) b a s e d c o m p u t e r c o d e s . For t h i s p u r p o s e , s o f t w a r e m o d u l e s are r e q u i r e d t h a t c a n ( 1 ) g e n e r a t e a mesh ( p r e - p r o c e s s i n g ) and (2) display the r e s u l t s of t h e a n a l y s i s f o r easy i n t e r p r e t a t i o n by the user (postprocessing). OK
The s o f t w a r e s h o u l d u s e s t a n d a r d o p e r a t i n g s y s t e m s and t e r m i n a l s , s i n c e t h e c o m p u t e r s may b e u s e d from t i m e to time f o r c o m p u t a t i o n s u c h a s FEM a n a l y s i s , o t h e r t h a n d e s i g n i n g and NC machlning of d i e s . a p r a c t i c a l CAD/CAM s y s t e m m u s t b e a b l e to c o m m u n i c a t e w i t h o t h e r CAD/CAM s y s t e m s f o r t h e purpose of e l e c t r o n i c d a t a and geometry transfer. O f t e n d r a w i n g s and o t h e r p a r t i n f o r m a t i o n are t r a n s f e r r e d " e l e c t r o n i c a l l y " f r o m o n e c o m p a n y ' s CAD/CAM s y s t e m t o a n o t h e r company or to a n o t h e r l o c a t i o n of t h e same company. T h u s , n e u t r a l f o r m a t s s u c h as IGES (Initial Graphics Exchange S p e c i f i c a t i o n ) GDS ( G r a f i s c h e s Kern S y s t e m ) , or V D A ( V e r b a n d D e u t s c h e r A u t o m o b i l h e r s t e l l e r ) must be a v a i l a b l e [ L a n g e and KOrner. 1 9 8 5 1 . O f t e n t h e I u s t i f i c a t i o n to p u r c h a s e a is b a s e d o n :
CAD/CAM
system
0
I m p r o v e d c o m m u n i c a t i o n b e t w e e n d e s i g n and m a n u f a c t u r i n g a n d / o r b e t w e e n c u s t o m e r and s u p p l i e r . Data are t r a n s f e r r e d v i a telephone l i n e s , t a p e s , O r disks. AS a r e s u l t , errors i n c o m m u n i c a t i o n a r e reduced.
o
R e d u c t i o n i n l e a d time. A l t h o u g h t h i s f a c t o r is u s u a l l y d i f f i c u l t to q u a n t i f y , i t may d e t e r m i n e w h e t h e r a n o r d e r w i l l b e r e c e i v e d or n o t .
0
I n t e g r i t y of data. Errors i n d e s i g n and i n t e r p r e t a t i o n b y d i f f e r e n t d e s i g n e r s are r e d u c e d or eliminated, s i n c e geometry c a n be c a r e f u l l y e x a m i n e d by zooming or d i s p l a y i n g d i m e n s i o n s .
3.
APPLICATION
OF
EXPERT SYSTEMS FOR IHITIAL PART
AND D I E DESIGN
c a n be c o n s i d e r e d a s tools for a u t o W h i l e CAD/CAM matic p r e p a r a t i o n o f d i e d r a w i n g s and NC c u t t e r p a t h (CAE) includes programs. Computer Aided E n g i n e e r i n g t h e p r e l i m i n a r y d e s i g n as w e l l as a n a l y s i s f o r optimum d i e d e s i g n . T h u s , CAE i n metal f o n n i n g i n c l u d e s t h e u s e of b o t h E x p e r t S y s t e m s and p r o c e s s simulation. T h e a p p l i c a t i o n o f E x p e r t S y s t e m s i n metal f o r m i n g is a r e l a t i v e l y new r e s e a r c h a c t i v i t y . A s seen i n F i g u r e 1, e x c e l l e n t a p p l i c a t i o n s f o r t h i s m e t h o d o l o g y a r e in: ( a ) d e s i g n i n g f o r p r o d u c i b i l i t y by a g i v e n p r o c e s s , and ( b ) t h e i n i t i a l d e s i g n o f t h e d i e s p r i o r to optimization v i a process simulation. An e x a m p l e f o r t h e f i r s t case is g i v e n i n F i g u r e s 3 a n d 4 f o r a r i b web t y p e f o r g i n g w h e r e t h e f o r g i n g design, s t a r t i n g w i t h t h e geometry o f t h e m a c h i n e d is b e i n g a u t o m a t e d b y and a s s e m b l y r e a d y p a r t , d e v e l o p i n g a n E x p e r t S y s t e m [Tang e t a l . . 1 9 8 5 ) . I n d e v e l o p i n g t h i s s y s t e m , t h e f o r g i n g d e s i g n know-how is c o m p i l e d i n a s t r u c t u r e d and s y s t e m a t i c f a s h i o n . I n a d d i t i o n , t h e E x p e r t System a l s o p r o v i d e s t h e e x p l a n a t i o n o n how t h e d e s i g n g u i d e l i n e s a r e s e l e c t e d and a p p l i e d . I n o r d e r to s i m p l i f y t h e geometry manipulation, t h e d e s i g n of f o r g i n g s is d o n e by c o n s i d e r i n g s e l e c t e d p a r t s e c t i o n s as s e e n i n F i g u r e 3. T h e s e c t i o n g e o m e t r i e s a r e m o d i f i e d to make a f o r g i n g from a machined p a r t , using design rules. The d e s i g n f e a t u r e s t h a t a r e e s t a b l i s h e d and/or modified include: the parting l i n e , the forging p l a n e t h e f i n i s h i n g a l l o w a n c e , t h e web t h i c k n e s s , t h e r i b w i d t h , t h e d r a f t a n g l e , and t h e c o r n e r and f i l l e t radii. The m p o r t a n t f a c t o r s a f f e c t i n g t h e d e s i g n of t h e f o r g i n g s are: t y p e of forging, (precision, b l o c k e r , or c o n v e n t i o n a l ) , f o r g i n g m a t e r i a l , f o r g i n g e q u i p m e n t , part c o m p l e x i t y , p r o d u c t i o n l o t s i z e , and forging temperatures.
s1c;i:ar d e v e l o p o e n t bias c o n c e n t r a t e d on round : o r y i n c ; s and was e x t e n d e d t o e s t m a t e c o s t s of p r o d u c t i o n [ T r c h c l r w i t c h , 19851. k.
i x ; ) e r t S y s t e n s :re a l s o b e i n g G e V k i o [ ; e d for o f s i g n of ; , r c : i o r n i n y or o l o c k e r d i e s in f o r g i n g w i t h f l a s h e n d for developinq tt.e E o r g i n g sequence in cold forging without flash. 0. p r o t o t y p e s y s t e m c a l l e d RID ( B l o c K e r I n i t l a 1 3 e s i g n ) e x p r e s s e s a rib-web c r o s s web t h i c m e s s . s e c t i o n i n t e r m s of r i n n e l g n t / v l d t h , c r a f t a n g l e , c o r n e r and f i l l e t r a d i u s a s s e e n i n Usincj s t o r e d r u l e s , :he T r o q r a c m o d i f i e s Figure 5 . t h e s e geometric v a l u e s t o come u s w i t t : an i n i t i a l S l o c r t e r o r p r e f o r m d e s i s n [ V e n u r i e t a l . , 1 3 8 6 1 . An FOPWEX, is a b l e t o a u t a n a t i c a l l y E x p e r t System. d e s i g n t h e forming sequence f o r 3 u l t i - s t a g e cold f o r q i n g of p a r t s w i t b . r e l a t i v e l y s i m p l e q e o m e t r i e s s u c h a s t h o s e F r o d u c e d by u p s e t t i n g and f o r w a r d et al., e x t r u s i o n operations Figure 6 [Sevenler 19C71. ?he system n e e d s f u r t h e r development to h a n d l e h o l l o w p a r t s formed by b a c k w a r o c a n e x t r u s i o n o p e r a t i o n s and is, i n p r i n c i p l e . s i a i l a r to s y s t e n s d e v e l o y e d e a r l i e r i n Germany [ R e b k o l z , 1 3 2 5 1 , f n q l a n d [ G O k l e r e t a l . , 1931). and I t a l y [ E a r i a n i an2 K n l q h t . i9851. 2 e c e n t l y a r e s e a r c n s t u u y was c o m p l e t e d On t h e d e v e l o p w 2 n t of an E x p e r t S y s t e m f o r e s t a b l l s n i n q t h e f o m i n y s e j u e n c e i n deb: d r a w i n g of a x l s y m m e t r i c s h e e t .neCal p d r t S LEshel e t a l . , 19861. T h l S SyStei:l rule-uased p r o t o t y p a p p e a r s t o be t h e rnos: a d v a n c e d process sequence a v a i l a b l e to a a t e f o r d e s i y n i n r j :he for G e e p a r a w n rouad p a r t s . 4.
CCKP3TER AIDE!:
TROCESS MODELIIIG FOR G I 2 DESIGLl
The m a i n o b ] e c t l v e s of p r o c e s s !?Odeling a r e to ( a ) i e t e r x l n e w h e t h e r t h e selected f o r m l n g p r o c e s s can p r o d u c e a g i v e n p a r t a s d e f i n e d 5.1 c j r o n e t r y and a a t e r i a l . ( L ) & e d i c t and a v o i d d e f e c t € o r n a t i o n , and ( c ) reduce p r o c e s s d e v e l o p m e n t and d i e r l e s i q n time and c o s t s . T h u s , as s e e n i n F i q u r e 1, t h e i n i t i a l d i e d e s i g n s u c ~ ~ e s t eby d e x p e r i e n c e c a n be v e r f i e d 5" simulating m e t a l flow throughout the f0rmlnq Jperation. T h u s , f o r m i n q e x p e r i m e n t s c a n be r u n on a c o m p u t e r and t h e r e s u l t s c a n b e d i s p l a y e d o n a graphics terminal. If the siaulatlon indicates that o r If t h e selected d l e d e s l q n does n o t f i l l t h e d i e . too :nuch m a t e r i a l w a s t e d , t h e n a n o t h e r d i e d e s i g n c a n be S e l e c t e d and t h e s i a u l a t l o n or " e x c e r i n e n t " c a n he r e p e a t e d and d i e d e s i g n and p r o c e s s c o n d l t l o n s c a n be optimized. AS a r e s u l t , c o s t l y a n d time c o n s u m i n g p r o c e s s d e v e l o p m e n t t r i a l s are a v o i d e d a n d p r o d u c t i o n e q u i p m e n t is n o t t i e d up f o r a e v e l o p i n g t h e f o r m i n g technique for a given p a r t . I n o r d e r to m o d e l or s i m u l a t e a f o r m i n g p r o c e s s , is n e c e s s a r y to h a v e :
a)
a m a t h e m a t i c a l model o f t h e p r o c e s s t h a t r e a l i s t i c a l l y represents the physical occur during the process,
b)
it
r e l i a b l e d a t a on t h e w o r k p i e c e a n d a s w e l l a s on m e c h a n i c a l , t h e r m a l boundary c o n d i t i o n s .
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T h e a v a i l a b i l i t y and r e l i a b i l i t y o f i n p u t d a t a i n t o a p r o c e s s model is e x t r e m e l y important s i n c e it d i r e c t l y i n f l u e n c e s t h e a c c u r a c y and r e l i a b i l i t y o f t h e p r e d i c t i o n s , e v e n i f t h e model c a n be c o n s i d e r e d t o be m a t h e m a t i c a l l y c o r r e c t and r e l i a b l e . The t y p e of input data necessary for s i m u l a t l n g forming p r o c e s s e s c a n be s u m m a r i z e d a s f o l l o w s :
a)
b e h a v i o u r of m a t e r i a l s u n d e r f o r m i n g c o n d i t i o n s . (1) c o n s t i t u t i v e This information includes: e q u a t i o n s i n s h e e t , b l l l e t , or com~actedpowder p r e f o r m , ( 2 ) t h e r m a l and p h y s i c a l p r o p e r t i e s of t h e w o r r p l e c e a n d d i e m a t e r i a l s a t f o r m i n g tenperarures, (3) formaoillty data, and (41 relationsnips between processing condltlons, m i c r o s t r u c t u r e s and p r o p e r t i e s .
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c h a r a c t e r i z a t i o n of c o n d i t i o n s a t d i e - m a t e r i a l i n t e r f a c e . T h i s i n c l u d e s f r i c t i o n and l u b r i cation, neat transfer coefficient, the relations h i p s between p r o c e s s c o n d i t i o n s and s u r f a c e f i n i s h and t o l e r a n c e s .
C)
d i e and m a c h i n e r e l a t e d i n f o r m a t i o n . T h i s i n f o r (11 d i e m a t e r i a l s a n d t h e i r m a t i o n c o n s i s t s of n e c h a n i c a l and t h e r m a l p r o p e r t i e s , ( 2 ) d i e g e o ( 3 ) r a t e o f metal f l o w a s d e t e r m i n e d m e t r y , and b y t h e d i e s and t h e m a c h i n e u s e d .
I n c o n s i d e r i n g p r o c e s s m o d e l i n g and a l e d e s i g n f o r metal f o r m i n g , it is a p p r o p r l a t e to o b s e r v e t h e d i f f e r e n c e s b e t w e e n s h e e t and m a s s i v e or Dulk-fOrming the processes. I n both c a s e s , t h e s u r f a c e s of
d e f o r m i n g m a t e r i a l a n d t h e d i e s a r e i n c o n t a c t , and f r i c t i o n b e t w e e n them h a s a m a j o r i n f l u e n c e o n t h e process. However, o t h e r differences in load. stresses, and s p r i n g b a c k influence d e s i g n and tolerances.
The c o d e PLADiYI ( P l a s t i c Deformation Analysis) d e v e l o p e d i n S t u t t g a r t ILanqe and Y o r n e r , 19851 h a s o e e n a p p l i e d to a v a r i e t y of f o r p i n g p r o c e s s e s and is being f u r t h e r developed. 8.n e x a i ~ p l e o b t a i n e d w i t h PLADP.PI is shown i n F i g u r e 7.
I n m a s s i v e f o r m i n g , t h e i n p u t m a t e r i a l is i n b i l l e t , r o d or s l a b f o r m , a n d a c o n s i d e r a b l e i n c r e a s e i n t h e s u r f a c e to volume r a t i o and c h a n g e s i n c r o s s - s e c t i o n s take place. T h e p o r t i o n of t h e w o r k p i e c e u n d e r g o i n g p e r m a n e n t p l a s t i c d e f o r m a t i o n is g e n e r a l l y much l a r g e r than t h e portion undergoing elastic deforAS a result, elastic recovery a f t e r mation. is n e g l i g i b l e but the deformation deformation stresses a r e much h i g h e r , t h r e e to ten times, t h a n t h o s e Observed i n s h e e t m e t a l forming.
I n t h e United S t a t e s , t h e fundamental s t u d i e s of t h e l a s t d e c a d e c o n d u c t e d a t Berkele:.' I K o b a y a s h i , 1 9 t 5 1 k a v e b e e n t r a n s l a t e d i n t o p r a c t i c a l c o m p u t e r codes by Dattelle [Oh and P . l t a n , 19851 and Marc I i n a l y s i s [Rebello,1906). I n a d d i t i o n , t h e code developed a t t h e Lawrence L i v e r m o r e L a b o r a t o r y f o r i n v e s t i q a t i n g i n p d c t tyFe phenonena h a s been a p p l i e d to s l m u l a t l o n of f o r g i n g p r o c e s s e s [ F l o w e r a n d H a l l q u l s t , 15861. T h e s e l a s t three c o d e s c a n h a n d l e n o n - l s o t h e c x a l f o r g i n g s i m u l a t i o n s p r o v i a e d v a l u e s for h e a t t r a n s f e r c o e f f i c i e n t s and o t h e r t h e r a a l c o n s t a n t s e x i s t as input.
I n s h e e t f o r m i n g , a s h e e t b l a n k is p l a s t i c a l l y object w i t h o u t deformed i n t o a three-dimensional s i g n i f i c a n t changes i n s h e e t thickness. I n some cases, t h e magnitude o f permanent p l a s t i c and recoverable elastic deformations a r e comparable; t h e r e f o r e , e l a s t i c r e c o v e r y or s p r i n g b a c k may be significant. T h u s , i t is a p p r o p r i a t e to c o n s i d e r p r o c e s s m o d e l i n g and d i e d e s i g n s e p a r a t e l y f o r s h e e t and m a s s i v e forming
.
5,
PROCESS SIMULATION FOR DESIGNING DIES FOR MASSIVE FORMING
During t h e l a s t d e c a d e , computer s i m u l a t i o n h a s been i n c r e a s i n g l y a p p l i e d t o m e t a l f o r m i n g processes u s i n g v a r i o u s methods o f p l a s t i c i t y w i t h v a r y i n g d e g r e e s of m a t h e m a t i c a l c o m p l e x i t y and r e l i a b i l i t y . The methods u p p e r bound o f a n a l y s i s used i n c l u d e slab method, m e t h o d , and f i n a l l y , t h e F i n i t e E l e m e n t Method, w h i c h i s now b e i n g f u r t h e r d e v e l o p e d i n v a r i o u s l a b o r a tories a r o u n d t h e world. While i n i t i a l a p p l i c a t i o n s o f s i m u l a t i o n were C o n c e n t r a t e d o n r o l l i n g , e x t r u s i o n a n d d r a w i n g , r e c e n t r e s e a r c h is h e a v i l y c o n c e n t r a t e d on forging [ P i t t m a n e t a l . , 1 9 8 4 , Boer a n d J o v a n e . 19841. T h e u p p e r - b o u n d e l e m e n t a l t e c h n i q u e , UBET, d e v e l o p e d b y B r a m l e y and h i s c o - w o r k e r s , c a n be u s e d to p r e d i c t f o r g i n g l o a d s , m e t a l f l o w , and l o c a l d i e p r e s s u r e i n a s s i s t i n g t h e d e s i g n of f o r g i n g d i e s [ G h o r r i a l et a l . 19851 a n d [ B r a m l e y , 1 9 8 7 1 . T h i s technlque needs r e l a t i v e l y m a l l c o m p u t i n g p o w e r and is s u f f i c i e n t l y a c c u r a t e i n p r e d i c t i n g t h e forging load v e r s u s d i e d i s p l a c e m e n t , and d i e f i l l f o r s i m p l i f i e d g e o m e t r i e s . However, i n g e n e r a l , i t is n o t a s a c c u r a t e a s t h e FEM-based p r o c e s s m o d e l s , e s p e c i a l l y i f the effects o f f i l l e t and c o r n e r r a d i i a r e i n v e s t i g a t e d . S e v e r a l FEM-based c o m p u t e r p r o g r a m s f o r s i m u l a t i o n of m a s s i v e f o r m i n g p r o c e s s e s are b e i n g d e v e l o p e d a r o u n d t h e w o r l d , i n p a r t i c u l a r , i n Swansea a n d Birmingham S t u t t g a r t , Aachen, and Hannover i n i n t h e U.K., Germany, K y o t o I n s t i t u t e o f T e c h n o l o g y and Kobe U n i v e r s i t y i n J a p a n , and C o r n e l l , B e r k e l e y , Marc Analysis, Battelle-Columbus, and Lawrence Livermore L a b o r a t o r y i n t h e United S t a t e s . A good o v e r v i e w of t h e s e d e v e l o p m e n t s is g i v e n i n t h e p r o c e e d i n g s o f t w o recent c o n f e r e n c e s [ L a n g e , 1 9 8 5 , P i t t m a n e t a l . , 19851.
i n Aachen, a h y b r i d method u s i n g b o t h t h e This FEM and t h e e l e m e n t a r y t h e o r y was d e v e l o p e d . axisymmetric and method s i m u l a t e s two-dimensional, p l a n e S t r a i n f o r g i n g o p e r a t i o n s w i t h r e a s o n a b l e accur a c y and w i t h o u t r e q u i r i n g v e r y l a r g e c o m p u t i n g power [ K o n i g e t a l . , 1 9 8 5 , Konig and Hofmann, 19861 This to f o r g i n g h y b r i d t e c h n i q u e h a s a l r e a d y been a p p l i e d of v a r i o u s g e o m e t r i e s , a s well a s to c o l d e x t r u s i o n of spur g e a r s . The r e s u l t s a p p e a r to be a d e q u a t e a s b o u n d a r y c o n d i t i o n s f o r e l a s t i c FEM a n a l y s i s o f t h e tool stresses a n d f o r e s t i m a t i n g d i e w e a r i n h o t forging A t t h e RWTH
AL?ID ( i i n a l y s i s ot L a r g e r l a s t i c I n c r e n e n t a l Deformat i o n ) was d e v e l o j e d j o i n t l y by i m t t e l l e and the U n i v e r s i t y of C a l i f o r n i a - C e r k e l e y w i t h su-,sort fron t 5 e A ~ K Force. it is now b e i n g u s e d s y v a r i o u s i o r g i n g and f o r m i n g c o m p a n i e s . An e x a m p l e o b t a l n e d w i t h t h e i s o t h e r n a l v e r s i o n Of ALPID is shown in Figur2 8 . "his f i g u r e i l l u s t r a t e s the d e f o r m t i o n The pattern in isothermal forqing a titaniun disk. i n a t e r i a l n e a r t h e f l a s h or p a r t i n q l i n e r e q u i r e s a g r e a t e r d e g r e e o f f r e e d o n t o a c c o n m o d a t e t h e coiny l i c a t e d flow p a t t e r n near t h e f l a s h zone. Therefore, t w o r e m e 5 h i n g o p e r a t i o n s w e r e n e c e s s a r y to a c h i e v e t h e f i n a l d e f o r m a t i o n shown i n F i g u r e 9 . T h r o u g h r e n e s h i n g ! a ) a new n e s h is a s s i q n e d t o accommodate t h e complex d e f o r m a t i o n T a t t e r n , and h ) t h e s t r a i n d i s t r i b u t i o n is l n t e r n o l a t e d f r o m t h e old mesh 3 n t o t h e new n e s h . T h i s r e n e s h i n q n r o c e d u r e is e x t r e m e l y i m p o r t a n t for s i m u l z t i n q F r a c t i c a l f o r g i n g o p e r a t i o n s w h e r e 1arc;e d e f o r m a t i o n s a r e p r e s e n t and t h e p r o p e r t i e s of t h e d e f o m i n s m a t e r i a l a r e d e t e r niined by t h e amount of d e f o r m a t i o n lmposecj o n t h e forged p a r t . P.n e x a m p l e o f t n e n o n - i s o t h e r m a l ALPID s l n u l a t l o n is shown i n F i g u r e 9 f o r u p s e t t i n g a c y l i n d e r . In t h i s case, t n e 1C20 s t e e l b i i l e t was r i e a t e d to 1232C m i l e t h e l n t l d l d i e tel:lyeratuKe WdS 204C. T;ie p r o c e s s V Z S consicered t o tarce p l a c e i n t h r e e u i s t i n c t ; i n a s e s where u i f f e r e n t h e a t t r a n s f e r c o e f f i c i e n t s a t t h e . x a t e r i a L - u i e i n t e r f a c e were assuaed i a ) t h e h e a t e d k l i i e t is p l a c e d tiFon t h e lover d i e a n d r e s t s for s i x s e c o n d s , b)
u p s e t t i n g s t a r t s and is s t o p p e e a t 67 p e r c e n t reu u c t i o n i n h e i g h t , 1.e. 1 . 5 s e c o n d s l a t e r , and
c)
t h e u p s e t b i l l e t r e m a i n s o n c h e lower h i e €or t h r e e secGnCis a f t e r tile to? a l e is removec.
rA'i~e p r e d i c t i o n s of
t e n p e r e t u r e s . l o a d , and n e t a l f l o k r e coinprea w i t h e x p e r l n e n t a i c a t h and the agreem e n t was s u i t e s a t i s f a c t o r y a 1 t h o r ; y h t h e r e s u l t s assumed h e a t d e p e n d e d c o n s i d e r a S l y on t h e v a l u e s of transfer coefficients. -m. * ~
i n g e n e r a l , ZEM p r o g r a i i s r e q u i r e a s i n p u t d a t a : 0
I n H a n o v e r . t h e r e c e n t l y d e v e l o p e d FEM p r o g r a m , FARM ( F i n i t e E l e m e n t A n a l y s i s o f R i g i d P l a s t i c Metal F o r m i n g ) h a s b e e n u s e d to e x p l o r e t h e o p t i m i z a t i o n o f d i e l i f e b y e x t e n d i n g t h e e x i s t i n g c o d e to c o n s i d e r The h e a t t r a n s f e r b e t w e e n t h e d i e s and t h e f o r g i n g . r e s u l t s of t h i s s t u d y i l l u s t r a t e d t h a t t h e d i e s are s u b j e c t to c o m p l e x t h e r m a l and m e c h a n i c a l s t r e s s e s a n d it is p o s s i b l e to u n p r o v e d i e l i f e by m o d i f y i n g t h e r h e r m a l c o n d i t i o n s i n t h e d i e s and by r e d u c i n g t h e t h e r m a l stress g r a d i e n t s [Ma and Weiss, 1 9 8 6 1 . T h e FEM m e t h o d is a l s o u s e d i n a j o i n t i n v e s t i g a t i o n b e t w e e n ARBED R e s e a r c h a n d t h e U n i v e r s i t y o f L i e g e [Groaer e t a l , 19851 for a x i s y m m e t r i c u p s e t t i n g a n d e x t r u s i o n and f o r p l a n e s t r a i n - r o l l i n g o p e r a t i o n s . T h e r e s u l t s a p p e a r to i n d i c a t e t h a t t h e method b e i n g d e v e l o p e d g i v e s good r e s u l t s a n d h a s p o t e n t i a l f o r f u t u r e expansion.
movement.
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n a t e r i a l p r o p e r t i e s . 1.e. f l o w s t r e s s i n f u n c t i o n o f t e m p e r a t u r e , s t r a i n r a t e and s t r a i n a s well a s t h e r m a l p r o p e r t i e s i n f u n c t i o n of t e m F P r a t u r e , bnd
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n e a t t r a n s f e r c o e f f i c i e n t in f u n c t i o n of pressure.
.
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uie data, 1.e. d i e g e o a e t r j ' , die f r i c t i o n a t die-material interface,
time znc!
T h e r e s u l t s o b t a i n e d f r o n a n XI s i m u l a t i o n i n c l u d e : 0
i o r g i n y load v e r s u s d i e s t r o k e .
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i . 1 a t e r i a l f l o w i n form o f modal v e l o c i t i e s and g r i d d i s t o r t i o n , and
0
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of: Stress, s t r a i n ,
s t r a i n - r a t e and
L ? m k f e rd t U KC'.
T h u s , iT1.1 p r o g r a ~ r ;o f f e r v e r y u s e f u l i n f o r m a t i o n f o r g r e u i c t i n g p r o > e c t i e s , SOUndneSS of formed p r o d u c t s , and d i e f i l l i n g . i : f t n o S s o t h e r t h a n FEN are a l s o e x t r e n e l y u s e f u l i n p r e d i c t i n g t h e p r o c e s s v a r i a c l e s and d e s i g n l n q 6 i e s f o r a l a r g e number of o p e r a t i o n s . For e x a m p l e , t h e C m p u t e r AiGed E n g i n e e r i n q S y s t e n , d e e l o p e c a t t h e I:arsaw U n i v e r s i t : i of Technology t a k e s i n t o a c c o u n t t h e tool l o a d i n g . t h e f r a c t c r e o f t h e f o r n e d r , a t e r i a l
457
i n che c e s l o n o u t s l u e t b e d e f o r n a t i o n zone and t h e d u c t i l e f r a c t u r e in the deformation zone lh'arciniak. A c o m p r e h e n s i v e CAD/CAV s y s t e m for practical 19E6l. d i e d e s i g n a n d m a n u f a c t u r l n g i n f o r g i n g 1s l n o p e r a tion i n Japan [ C o t o h , 19251 a n d i s p l a n n e d in Eelqium [ K r u t b , 19371. I n a d d i t i o n . a l a r g e number o f computer a i d e d n o d e l s bave been developed for the a n a l y s i s o f o t h e r n a s s i v e f o r m l n y o p e r a t i o n s , s u c h as s h a F e and r i n g r o l l i n g . e x t r u s l o n . and i r o n i n g . 6,
PROCESS SIE!ULATIOll FOP SHEET NETAL FOPI.!It:C
S i m u l a t i o n of s h e e t f o r m i n g p r o c e s s e s h a s b e e n t h e s u b j e c t o f a l a r y e number of s t u d i e s t h r o u g h o u t t h e worli. >lost o f t h e models d e v e l o p e d so f a r d e a l w i t h a x i s y m m e t r i c and p l a n s t r a l n d e f o r m a t i o n c o n d i t i o n s . Conpurer prograns f o r slinulation brake bending, roll bending, and punch S t r e t c h i n g rubber tormlng. nave been s u c c e s s f u l l y developed [Hagpal e t a l . , i 5 8 2 , Uh a n d K o b a y a s l l l , i9221. I n a l l t h e s e prociata o n s h e e t t h i c k n e s s , tool g e o m e t r y , grass, . a a t e r i a l f l o w s t r e s s , a n d f r i c t i o n a r e u s e d to p r e t i i c t , s t e p oy s t e p , t h e i n s t a n t a n e o u s s h e e t g e o m e t r y , tile s t r a i n s i n t h e s h e e t , a n d t h e l o a c ' versus stroke A s a n e x a m p l e , t h e r e s u l t s €or b r a k e b e n d i n g curve. are i l l u s t r a t e d i n f i g u r e 10. In t h i s figure, the h c e s s r a n a n d t h e b e n t s h e e t a r e shown s c h e m a t i c a l l y f o r v a r i o u s s t r o k e p o s i t i o n s during t h e bending operation. i?ecently, t h i s w o r k h a s b e e n e x p a n d e d to s i m u l a t e t h e d e e p drawing o f round c u p s o f v a r y i n g cross s e c t i o n s [ V e m u r i e t a l . , 1 9 2 6 1 . c o m p u t e r code, c a l l e d SHEETS, was r e c e n t l y a p p l i e d t o s i m u l a t e p l a n s t r a i n and a x i s y m m e t r i c s h e e t form-
; i
ing
under production c o n d i t i o n s [Lee and Forth. T h e s c h e m a t i c o u t l i n e o f t h e m o d u l e s of t h i s is s e e n i n F i g u r e 11. T h i s i n t e g r a t e d code :rogram is c a p a b l e o f p r o v i d i n g a n i n s t a n t a n e o u s g r a p h i c r e p r e s e n t a t i o n of t h e degree o f s u c c e s s or f a i l u r e i n t h e formability of sheet n e t a l p a r t s at the design s t a g e . Key e l e m e n t s o f t h e a n a l y s i s p r o g r a m s c o n s i s t o f c o n s t i t u t i v e e q u a t i o n s , forming l i m i t diagrams, and f i n i t e element a n a l y s i s programs.
i9131.
The forming of axisymnetric s h e e t metal p a r t s can also ue 6 n a l y z a c ; u s i n g a p r o g r a m , c a l i e d AXIFORH [Gerdren, l9341. T h i s p r o g r a m is u a s e d o n l a r g e d e f o r x a c i o n and l a r g e - s t r a l n t h e o r y of p l a s t i c i t y . It includes combinations of s t r e t c h i n g , bending and d r a w i n g modes o f d e f o m a t i o n . thickness variations, s t r a i n h a r d e n i n g and m u l t i p l e stages o f forming, capabilities f o r predlCting residual stresses, o r i g i n a l blanK s i z e and f o r m i n g l o a d . Computer a i d e d d e s i g n and s i m u l a t i o n f o r forming o f non-symmetric s h e e t netal parts have also been attemGted with consideraole success. In one s t u d y . c h 7 p u t e r l z e d s l i p l i n e f i e l d m e t h o d h a s b e e n u s e d to a n a l y z e t h e stresses, p r e d i c t t h e m a t e r i a l f l o w , a n d estimate t h e i n i t i a l b l a n k g e o m e t r y [ G l o e c k l and L a n y e , 13831. More r e c e n t l y , a f i n i t e e l e m e n t p r o c e U u r e h a s Deen d e v e l o p e d f o r m o d e l i n g t h e d r a w i n g p r o c e s s f o r s q u a r e c u b s b a s e d o n f i n i t e s t r a i n formul a t i o n a n d m e m b r a n e t h e o r y [ K o b a y a s h i , 19851. The s h e e t m a t e r i a l was a s s u m e d to b e a n i s o t r o p i c a n d s t r a i n h a r d e n i n g w h i l e Coulomb f r i c t i o n was c o n s i d e r e d a t tool-material i n t e r f a c e . S i m u l a t i o n s were conducted f o r various blank shapes with i d e n t i c a l Good c o r r e l a t i o n s were s u r f a c e a r e a s , Figure 12. found between p r e d i c t e d and measured v a l u e s o f punch l o a d s and o f deformed f l a n g e g e o m e t r i e s . e L ! u l a t i o n o f more c o m p l e x a n d t r u l y 3D s h e e t f o r m i n g o p e r a t i o n s are b e i n g a t t e m p t e d b y n e a r l y a l l a u t o m o t i v e companies around t h e world. Companies such as GM. F o r d , C h r y s l e r , T o y o t a a n d O t h e r s a r e d e v e l o p i n g , o n o n e h a n c . C o m p u t e r I n t e g r a t e d M a n u f a c t u r i n g (CIM) a n d , o n t h e o t h e r h a n d , FEM-based p r o g r a m s f o r t h e simulation o f complex s h e e t forming o p e r a t i o n s [ C r e s t i n a n d Kci,:aters, 1 3 8 6 , Gang a n d T a n g , 1 9 8 5 1 . ; c h i l e c h e CI:.: s y s t e m s are p r o v e n to b e f u n c t i o n a l a n d & r a c t l c a l , t h e 3D s i m u l a t i o n m e t h o d s s t i l l u s e s u p e r conijuters a n d are s t i l l n o t q u i t e i J r a c t i c a l , e x c e p t tor a f e w r e l a t i v e l y s i m F l e cases. 7.
DIE MANUfACl'URING
AND MAINTENANCE
Various die manufacturing techniques, e.g., c a s t i n g , Cold a n d h o t h o o b i n y , c o p y m i l l i n g , CNC n a c h i n i n y , a n d E W l by u s i n g co;y m i l l e d or QJC m a c h i n e d electrOdeSr dre well-Known. I n e a c h s p e c i f i c applicat i o n , d e p e n d i n g upon t h e specific c o n d i t i o n s and t h e t e c h n o l o g y a v a i l a b l e , o n e or more of t h e s e t e c h n i q u e s a r e selected. I n t h e a u t o n o t i v e i n d u s t r y , t h e emphasis i n nanufact u r i n q Of s h e e t f o r m i n g d i e s is o n i n t r o d u c i n g a C m p u t e r I n t e g r a t e d System. Briefly, i n such a
s y s t e m t n e p a r t d e s i g n is e i t h e r u i g i t i z e d from a c l a y m o a e l or o b t a i n e d f r o m a 3D CAD model. After adaing the appropriate peripherial geometric features for b l a n k h o l d i n g a n d c o n t r o l o f t h e m a t e r i a l f l o w , t h e d i e is c a s t u s u a l l y v i a t h e l o s t - € o a m t e c h n i q u e . FOC t h i s purpose, t h e s t y r o f o a i n p a t t e r n s a r e CNC , n a c h i n e d u s i n g t h e g e o m e t r i c d a t a f r o m t h e same p a r t d a t a base. T h e c a s t d i e c a v i t y is CNC m a c h i n e d to final tolerances. The machining marks a r e u s u a l l y r e m o v e d b y hand g r l n d i n g a n d p l i s h i n g . T h e t r e n d is t o u s e f i v e - a x i s m a c h i n i n g w h i c h a ) is more e f f i c ient, s i n c e f l a t - e n d m i l l s with l a r g e metal removal c a p a b i l i t y c a n be u s e d , a n d b ) p r o v i d e s a b e t t e r s u r f a c e f i n i s h and r e d u c e s t h e need for surface f i n i s h i n g and p o l i s h i n g IKonig and K o l l i n g , 19861. T h i s l a t t e r o p e r a t i o n is q u i t e l a b o r i n t e n s i v e . Therefore, a u t o m a t i c d i e p o l i s h i n g machines have is beinq r e c e n t l y been introduced. Research c o n d u c t e d f o r d e v e l o p i n g more e f f i c i e n t a n d p r a c t i c a l d i e p o l i s h i n g t e c h n i q u e s [Nakagawa, 19861
.
Dies f o r massive forming without f l a s h , i.e., f o r c o l d a n d warm f o r g i n g , a r e u s u a l l y a x i s y m m e t r i c or n e a r l y so. T h e y a r e u s u a l l y m a c h i n e d b y CNC t u r n i n g non-sysmmetric feaw i t h p o s s i b l e a d d i t i o n a l EDM o f tures. T h e s e u i e s are h i g h l y stressed; t h e r e f o r e , r i n g s 1s t h e d e s i g n of t h e d i e s and t h e s h r i n k - f i t .nost c r i t i c a l from t h e p o i n t o f v i e w o f r e s i s t a n c e t o nechanical tatique. The g r i n d i n g , f i n i s h i n g , and s t r e s s r e l i e f o p e r a t i o n s are c r i t i c a l s t e p s i n manut a c t u r i n g such dies.
I n nanufacturing of dies f o r forging with f l a s h , t h e I n some c a s e s , t r e n d is t o u s e EDM [ K r u t h , 1 9 8 6 1 . e s p e c i a l l y i n m a k i n g l a r g e d i e s , ECM or QK m a c h i n i n g Here t h e may be u s e d a s a r o u g h m a c h i n i n g s t e p . t r e n d is to u s e CAD/CAM s y s t e m s f o r g e n e r a t i n g t h e NC the t a p e i m a g e a n d to m e a s u r e t h e d i m e n s i o n s o f i n a c h i n e d d i e c a v i t y v i a a CMM, u s i n g t h e Same g e o a e t r i c d a t a b a s e for a l l : d e s i q n , CNC m a c h i n i n g ; a n d d i m e n s i o n a l i n s p e c t i o n [ E n g e l i , 19861. I n CNC m a c h i n i n g , t h e t r e n d is to make e x i s t i n g s o f t more u s e r - f r i e n d l y a n d e a s i e r t o l e a r n [i:elbourn. 19841. As in other engineering software packages, a m i g r a t i o n of NC machininq software towards micro c o m p u t e r s a n d e n g i n e e r i n g w o r k s t a t i o n s is o b s e r v e d . I n t e r e s t i n g s o f t w a r e d e v e l o p m e n t s are c a r r i e d o u t to a p p l y s o l i d m o d e l i n g to s i m u l a t i o n a n d v i s u a l i z a t i o n of t h e d i e m a c h i n g o p e r a t i o n [Walsham and Knight, 19851. O b s e r v i n g t h e tool a n d t h e d i e s u r f a c e b e f o r e and a f t e r m a c h i n i n g i n s h a d e d p h o t o the generated l i k e form m a k e s t h e v e r i f i c a t i o n o f c u t t e r paths q u i t e easy.
ware s y s t e m s
T h e u n d e r s t a n d i n g o f d i e f r a c t u r e a n d w e a r is t h e s u b j e c t o f s e v e r a l new i n v e s t i g a t i o n s [ R e i S S , 19861. E x t e n s i v e s t u d i e s o n t h e u s e of s u r f a c e c o a t i n g s a n d t r e a t m e n t s to i n c r e a s e a b r a s i v e d i e wear a r e b e i n q [Meist a n d W e s t h e i d e , conducted around t h e world It appears that 1 9 8 6 , Konig and T r e p p e , 19861. f u n d a m e n t a l k n o w l e d g e o n t h e r e l a t i o n s h i p s of d i e s u r f a c e stresses, t e m p e r a t u r e s , a n d r e l a t i v e m a t e r i a l v e l o c i t i e s are n e c e s s a r y i n Order to f u l l y u n d e r s t a n d t h e p h e n o m e n o n o f d i e wear a n d to p r e d i c t when d i e s h a v e to be m a i n t a i n e d a n d / o r e x c h a n g e d f o r p r e v e n t i v e maintenance purposes. ACKNOKLEDGENENTS T h i s paper h a s b e e n p r e p a r e d w i t h i n p u t f r o m a n u m b e r o f CIRP c o l l e a g u e s a n d o t h e r e x p e r t s . The a u t h o r would l i k e to a r a t e f u l l v acknowledae t h i s a s s i s t a n c e as f o l l o w s : K.
E.
w.
B r a m l e y , CAD of F o r g i n g D i e s Doege, A n a l y s i s o f F o r g i n g a n d R o l l i n g P r o c e s s e s A. K n i g h t , CAD/CAM, S o l i d M o d e l i n g a n d F o r g i n g
Dies K o e n i g , T e c h n o l o g y o f D i e M a c h i n i n g , CAD o f F o r g i n g Dies, S u r f a c e T r e a t m e n t a n d D i e Wear H . Kudo, CAD of D i e s for M a s s i v e F o r m i n g , CAM o f S h e e t Metal Dies b y J a p a n e s e A u t o m o b i l e Manufacturers J . P . K u r t h , CAD/CAM o f F o r g i n g and I n j e c t i o n M o l d i n g Dies K . L a n g e . C l a s s i f i c a t i o n o f Dies. D i e Wear i n C o l d Forging, Analysis of Deformation 2 . M a r c i n i a k , CAD of M a s s i v e a n d S h e e t f o r m i n g processes m I. Nakagawa, V a r i o u s D i e Making and P o l i s h i n g Techniques J . R e i s s n e r , CAD/CAM i n S h e e t Metal F o r m i n g D. B. t i e l b o u r n , CAD/CAM o f Dies a n d A p p l i c a t i o n s i n Foundry
w.
I. a n d C e q e l . Y., Jar.. 1 9 0 2 , D e s i g n a n d Yanu f a c t u r i ng ( CPW/CAf.' ) o f iiot Forging D i e s . J. Applied Y e t a l u o r k i n y , 2, :io. 2 , b. 77. A l t a n , T., und B i i l h a r d t , D. F . , G C t . 1923. A p F l i c a t i o n of CAD/CAM i n E x t r u s i o n A Management G v e r v i e w . L i g h t ?,eta1 Acje, , 24. A l t a n , 'J., C:i. 6. I . a n d Gegel, i i . , :,!eta1 Forming, i 9 3 3 , X e t a l ForminJ: F u n d a m e n t a l s and A+;iications, m e r i c a n S o c i e t y c;€ :,letals, e e t a i s P a r K , cii. A l t a n , T. a n d G h , S. I . , 1 9 8 4 , CA3/CAbi o f T o o l i n y , E q u i p n e n t and P r o c e s s for P l a t i c i i o r i t i n y , P r o c e e d i n g s of t h e 1st I n t e r n a t i o n a l C o n f e r e n c e o n t h e T e c h n o l o g y of P l a s t i c i t y , T o k y o , p. 5 3 1 . C a c i a n i , P. a n d K n i j i h t , i:. A . , 1 9 D 5 , C o c p u t e r A i d e d Cold Forqing P r o c e s s Design: Determination of # a c h i n e S e t t i n g C o n d i t i o n s . A n n a l s of CIRP, V o l . 3 4 , !!o. 1, 245. D r a m l e y , A . f!., C o m p u t e r A i d e d F o r g i n g D e s i g n , p a p e r s u b m i t t e d to CIP? A s s e m b l y . A u g u s c , 1 9 E 7 , t o o e ; ; u o l i c h e c i i n CIR? A n n a l s . roec, C. 2 . a n d J o v a n e , R . , 1 9 2 4 , C o n p u t e r P.ided C e s i g n in Metal F o r m i n g S y s t e m s , A n n a l s of C I R P . L'Ol. 3 3 , IJO. 2 , r,. 4 3 3 . C r e s t i n , J. P . a n d ' C K a t e r s , J. F. ( e d i t o r s ) , 1 9 2 5 S o f t w a r e f o r Dicrete h!anufacturing. P r o c e e d i n q s o f t h e 6 t h I n t e r n a t i o n a l IFIP/IFAC c o n f e r e n c e . PirOLhPiAP 35, P a r i s , ~ u b l i s h e d by :;OCth i l o l l a n d . P n g e l i , it., 192C, COKLI3- e i n e i n t e g r i e r t e CAD/CAM L o s u n g , T e c n n i s c h e R u n a s c h a u , Vol. 2 0 . p. 1 5 6 . E s h e l , c:., J a r a s h , i.!. and J o h n s o n , L., 1 9 0 6 . R u i e E a s e d # o d e l i n g f o r P l a n n i n g A x i s y . m e t r 1 c Deep o r a u i n g , J. I,.ech, L l o r k i n y T e c h n o l o g y , 1 4 , p . 1 . F l o k e r , E . C. a n u H a l l ~ u l s t ,J . , J u l y 1 9 8 6 , F o r g i n g DY Conktiter pays Oft, iimerican b:achinist and Automa tec M a n u f a c t u r i n g C e r d e e n , J.C., ;.:a? 198.4, D e v e l o p n e n t of a C o m p u t e r P r o g r a m - AXIFG.?:.: f o r t h e A n a l y s i s o f F o r m i n g oE A x i s p e t r i c S h e e t .*!eta1 P a r t s , P r o c e e d i n g s of LIAXRC X I I , I . i i c h i g a n T e c h . u n i v e r s i t y , i l o u g h t o n , ?:I, , p. 2 4 3 . C h o b r i a l , i.!. I . , Osman, F. ii., a n d B r a m l e y , A. : I . , 1 9 8 5 , F o r g i n g F l a s h C e s i g n U s i n g WET, P r o c e e d i n g s o f NAMRC-XIIX, P e r k e l e y , C a l i f o r n i a , , p. 151. G l o e c k l , t i . a n d L a n g e , K., # a y 1 9 3 3 , C m p u t e r A i d e d E e s i g n o f t 7 l a n k s for Deep Drawn I r r e g u l a r S h a p e d C o m p o n e n t s , P r o c e e d i n g s o f tIAI.!RC X I , p. 2 4 3 . Goklar. :,I. I . , D e d n , T. A. a n d K n i g h t , h . A . , S e p t e i a b e r 1 9 0 1 , C m p u t e r Aided S e q u e n c e D e s i g n f o r liOt U>Sht F O c S i n y S , T r o c e e d i n g s O f t h e 22nd SITDR C o n f e r e n c e , x a n c h e s t e r , i ~ l a c m l l l a n , L o n d o n , p. 4 5 7 . C o t c n , i?., May, 1 9 8 5 , CAD/CA:< f o r Drop F o r g i n g , J . J a p a n S o c i e t y for T e c h n o l o g y o f P l a s t i c i t y , V. 2 6 ,
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C . dnd k i s s , U . , September 1966. S l m u l i e r u n g bnd O p t i m i e r L n q e i n e s G e s e n k s c h m i e d e p r o z e s s e s m i t .ier P I n i t e P l c n e n t e " e t h o d e , F i n a l R e p o r t f o r d e s e a r c h P r o l e c t Do 1 9 0 / 3 7 , I n s t i t u t f u r m f o r m t e c h n i K und L i n f o r m m a s c h i n e n , U n i v e r s i t a t f t a n n o v e r . a r c i n i a k , Z . , 1 9 8 6 , CAF S y s t e m f o r M e t a l F o r n i n g P r o c e s s e s . Users F ' a n u a l , T e c h n i c a l U n i v e r s i t y of l l a r s a w , I n s t i t u t e for M e t a l w o r k i n q . W e l d i n q a n d Casting. r i a q u a i , 'J. e t a l . , 1 9 8 2 . C o m p u t e r A i d e d M o d e l i n g o f S e l e c t e d S h e e t Forming P r o c e s s e s , i n F o r T a b i l i t y of Pletallic Materials 2000 A . D . , J . R. Newby a n d 3 . A. l l i e i e i e r , Rls., ASTM. p. 2 6 3 . h a a a g a w a , T., 1 9 2 7 , b l e w T e c h n o l o g i e s of " e t a 1 ? o n n i n g , A n n a l s o f CIRP, V O I . 2 , 481. G h , b. I . a n d A l t a n . '1.. D e c e m b e r 1 9 8 5 , F o r g i n g D e s i y n w i t h F F P , CAE J o u r n a l , p . 7 6 . ah..,. i . dnd K o h a y a s h i , S., 1982, k i n i t e F l e m e n t A n a l y s i s ot P l a n e S t r a i n S h e e t D e n d i n y , I n t . J . Of . , e c h . 6 c i . . Vol. 22. F . 5 6 3 . P l t c n c n , J . F. T . et a l . , 1 9 0 4 , e d i t o r s , N u l e r l c a l A n a l y s i s o f rorrning P r o c e s s e s , J o h n h i l e y and Lens, L t d . d e b e l l o , h . , F e b r u a r y 1 9 8 6 , F i n i t e E l e m e n t s for e e t t e r C o r g i n g , l l a c h i n e D e s i g n , p. 5 2 . deonolz, M. A p r i l 1 9 6 5 , R e c h n e r u n t e r s t u t z t e ~ r n i t t l u n gv o n S t a d i e n f o l g e n i n d e r Y a s s l v u m f o r i i u n g , P r o c & e d i n g s of t h e 7 t h I n t e r n a t i o n a l C o l d F o r g i n g C o n g r e s s , U n i v e r s i t y of Oirminyhain. Reiss, ti., 1 9 0 6 , A S t u d y o f D i e F r a c t u r e i n Cold Bulk e t a 1 F o r m i n g , P r o c e e d i n q s oE t h e 2 6 t h MTDP, a n c h e s t e r , p. 4 2 5 . R e i s s n e r , J. a n d C h r i s m a n n . R . . Y a r c h 1 9 8 6 , S i g n i f i c a n c e of S i m u l a t i o n f o r D e s i g n a n d M a n u f a c t u r e in S h e e t N e t a l W o r k i n g , p a p e r i n p r e p a r a t i o n . p r i v a t e c o m m u n i c a t i o n w i t h J. R e i s s n e r . S e v e n l e r , K. R a g h u p a t h i , P. S . a n d A l t a n , T., 1 9 8 7 , F o r m i n g S e q u e n c e D e s i g n for b " u l t i - S t a g e C o l d F o r g i n g , J . o f M e c h a n i c a l t l o r k l n q T e c h n o l o g y , 1 4 , p. 121. T a n g , J. P . , Oh, S . I . and A l t a n , T . , May 1 9 8 5 , A p p l i c a t i o n o f E x p e r t S y s t e m s to A u t o m a t i c F o r g i n g o e s i y n , IIAMRC-XIII, B e r k e l e y , C a l i f o r n i a , p . 4 5 6 . T ' i c n x i e w i t c h , S . , l l o v e m b e r 1 9 8 5 , P r i s e e n Compte d e C o n t r a i n t e s Necaniques et T e c h n o l o g i q u e s d a n s l'oprimization des btructures, Application a 1 ' Cbtdfliprrye., T e n c a n c e s A c t u e l l e s e n C a l c u l d e b t r u c t u r e , LAS'i'IA, E d i t i o n P l u r a l i s , p. 8 0 1 . V e m u r i . K. R. R a g h u p a t h i . P . S . , a n d A l t a n , T . , May 1986, A u t o m a t i c D e s i g n of B l o c k e r F o r g i n g Dies, PIAMRC-XIV, U n i v e r s i t y o f Y i n n e s o t a , M i n n a p o l i s , MN. p. 3 7 2 . ,:alsham, P. A . , a n d K n i g h t , 1 9 8 5 , A S o l i d M o d e l i n g AFprOaCh to NC P r o c e s s i n g : Sane F u r t h e r D e v e l o p m e n t s , P r o c e e d i n g s of t h e 2 5 t h MTDR C o n f e r e n c e , f l i r m i n q h a m , p. 1 3 3 . brig, N. k . a n d T a n g , S . C . ( e d i t o r s ) , 1 9 8 5 , Canputer i 4 o o e l i n g o f S h e e t M e t a l Forming P r o c e s s e s , P r o c e e d i n g s Ot T h e 1 2 t h A u t o m o t i v e M a t e r i a l s S y m p o s i u n , Ann A r b o r , p u b l i s h e d by t h e Metallurgical Society. > r e l b o u r n , D. B., 1 9 8 4 , C o m p u t e r A i d e d E n g i n e e r i n g (CAD/CAM/DUCT) i n t h e F o u n d r y , p a p e r p r e s e n t e d a t BCIXA C o n f e r e n c e , U n i v e r s i t y o f Vrarwick.
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C r O b e r , :i. e t a l . . O c t . 1 9 8 5 , N u m e r i c a l S i m u l a t i o n o f Metal F o r m i n g P r o c e s s e s , P r o c e e d i n g s I n t . C o n f . o f H o n - L i n e a r ECechanics, S h a n g h a i . S c i e n c e P r e s s , Z e i j i n g , C h i n a , e d . C h i e n Wei-Zang. K o b a y a s h i , G . , :.:ay, 1 9 8 5 . "Deformation A n a l y s i s a n d B l a n k C e s i g n i n S q u a r e Cup D r a w i n q " , P r o c e e d i n g s o f t h e 1 2 t h NSF C o n f e r e n c e o n P r o d u c t i o n R e s e a r c h a n d T e c h n o l o g y " , U n i v . of V ' i s c o n s i n . K o b a y a s h i , S . , 1985. :,!eta1 F o r m i n g a n d t h e F i n i t e E l e m e n t Method P a s t a n d F u t u r e , CIRP A n n a l s , VO1. 2 p. 1 7 . K o n i g . ;;., a n d E o f n a n n , H . ti.. 2 2 , 1 9 8 6 , S i m u l a t i o n s rechnung b e i m ZahnradfliessFressen, I n d u s t r i e A n z e i g e r , ?!o. 3 2 . V. 108. p. 1 6 . K o n 1 3 , id. a n d K o l l i n q . ti. D.. 1 9 8 6 , I n d u s t r i e A n z e i g e r . NO. 1 2 . V o l . 1 0 3 , p. 6. K o n i g . i;.. S t e f f e n s , i;.. a n d B i e k e c , R . ?;arch 2 9 , 19C5, CP.D-No6uln z u r S t o f f f l u s s s i m u l a t i o n , I n c u s t r i e m z e i g e r , :JO. ZG, V. 1 0 7 , p. 22. Soni;. K. anci T r e P F e , F . , 1986, L a s e r w a r m e b e h a n d l u n g von Kerxzeugtn, I n d U S t C i e Anzeiger, Vol. 97, p . 2c. K r u t n , J. P . , 1 9 8 6 . S t e p s T o w a r d s an I n t e g r a t e d C.%D/CAX S y s t e n f o r Mold D e s i g n a n d M a n u f a c t u r e , A n n a l s of t h e CIRP. Vol. 3 5 , 110. 1, p. 8 3 . K r u t h , J. P.. :987. G e l g i a n P r o j e c t o n CAD/CAM a n d S i r n u l a c i o n of t h e P r o d u c t i o n of F o r g i n g D i e s , P r i v a t e Comrnunica t i o n . L a n g e . K., 1 9 7 1 , i I o h 1 f o m w e r k z e u g e f u r U r f o r m - a n d U n f o m v e r f a h r e n , V D I - E e r i c h t e NO. 1 6 6 , p. 8 3 . L a n g e , K. 1 9 0 5 , editor, S i m u l a t i o n of Metal F o r m i n g P r o c e s s e s by t h e F i n i t e Element Method, h'orkshop Proceedings, Sttittgart. L a n g e , K - a n d KOCneC, E. 1 9 8 5 , U n f o r m w e r k z e u q e , P r o c e e d i n g s o f t h e FTK-1985, S t u t t g a r t , S p r i n q e r ' l e r l a a , p. 150. L e e , 5 . a n d F o r t h . C. M . , 1 9 8 3 , D e v e l o p m e n t o f a Corr.L.utec-P.icied A n a l y s i s Method for S h e e t M e t a l F o m i n g P r o c e s s e s , The 30th Sagamore ~ r m y , * : a t e r i a l s ? e s e a r c h C o n f e r e n c e , Lake L u z e r n e , w , S y r a c u s e U n i v . P r e s s . p. 1.
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macninins, y r i n o l n q a n a a s s e m o l y , most a i s c r e t e * a r t s m u s t f i r s t oe n l a n u t a c t u r e d to n e a r finish o i m e n s i o n s v i a o n e ot t h e " n e t or n e a r - n e t " shaping processts: ( a ) aelt processing (castin$, i n - ~ e c t i o n n o i ~ i n y ) , ( b ) s h a k i n g from powder , (c) f o r m i n q f r o a s n e e t , dnd ( c i ) form inc , trom b i l l e t . in ail t h e s e p r o c e s s e s , g e o m e t r y is t n e common t h r e a d a n d t h e t e c h n o l o g y ot dre/nola d e s i g n a n d manutact u r i n i , is a most s i g n i r i c s n t c o n s i d e r a t i o n . Z K ~ O Kto
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n e t s h a p e m a n u t d c t u r i n g F r o c e s s , d i e s are u s e d t r a n s f o r m a p i v e n material, u s u a l l y s n a p e l r s s OK a simple cjeometry, i n t o d u s e t u l ?art. The r e s u A t i n s part n a s d c o n p l t x geometry w i t h weilG e i i n e d s h a p t , s i z e , t o l e r a n c e s , a k p e a r a n c e and pro3ertit.s [ A i t h n e t a l . , 19831. The d e s i r e d p a r t yeometry 1 5 storea i n d i e s a n a m olds a nd i m p a r t e d o n t o t h e . . , a t e r i a l w i t h or w i t h o u t p r e s s u r e t h r o u g h t h e oie-m.teriai interface.
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p l q s i c a i pnenomena a e s c r i o i n g a n e t s h a p e manur o c t u r i n g p r o c e s s are u l r f l c u l t t o e x p r e s s w l t h q u a n titative rerptwnsnips. T he m a t e r i a l t i o w , the c o n , e n t r u i i o n a n 6 t r i r n s z e r a J r i n 5 tr'e rrocess a n a t1.e rti-t L U I ~ I . L ~ ~" t t w e e n >KOCCSS v a r i d u i e s an0 t n e pCOclJCt 2fG>t!Ctlr5 uKf2 O l f L l C L L t t O >KecllCt. hb a e e s u - L , c . i c ~ e s i q is ~ IL,ore a n a r t trian 6 s c i e n c e . i c . e a i A b , t r r t e n 4 i n t e r i n q u e s i i n DL u i e s c o n s i s t s of: ~ l s t ~ u ~ i b i ~ ti rni ec ,a i n e n i a t i c r e i d t i o n s n i p s (shapt, v e i o i i ~ i t s , s t r a i n fates, s t r a i n s ) bttween t h e i n c o n i n q ~ i c l t e r l d lGnu t n e stla>ro p r o d u c t , i.e. preu i ~ i l r i $I.iacerlal r l o u , ( 0 ) e s t a u i l s n l n y t h e l i h i l t s of >rwLciuirici, i.e. ~ e t e r ~ l i n i n y whtthhr it is p o 5 5 ~ 0 ~ et~ ssihre t n e part u i ~ n o u c s u r r a c e or in:ernnl l o i & r t , a m ( c ) r r e u i c t i n y t h e torces a n c stresses n r c e s s e r y t o e x e c u t e tire s n a p i n q o ? e r a t i o n s o c h a t t o o i i n b -no %uipiaient c a n be d e s i g n e d a n o The
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s c i e n t i f i c o e s i q n or the a l e s , i t is necessari t o corisiuer e a c n i n d i v i o u a r n e t S h a p e .i~anLracturinq a5 a s y s t e m , c o n s i s t i n $ of ( a ) 1 r . c ~ i~n. $ : , b t e r i a i anu its p r o p e r t i e s u n d e r p r o c e s s i n y ~ i e s , inchdin$ Geometry, c o n ~ i t i u n s , (t) the i i a t t r i ~ r b, u r r h c t t i n i s n , a n o t e m p e r a t b r e s , ( c ) c o w l c i m s ox i r i c i l ~ na n6 n e a t t r a n s f e r a c ;ie-iitaterial I r l L e x a c e , ic) tile l a e c n a n i c s 01 s n a p c n a n s e , ( e l t h e &,i.ir...ent ~ s e u , u i t n its v e i o c i t j , rorce, riqt6ity nno ro;rer C d p a U i A l t i e b , ( f ) t n e r ~ a nu ~ i t s pro~ ,brties, e n c ( 5 ) ti.= pl-rit environment incluainq ..u;..an eCOnG~..iL i a L C O K S .
W i t h t h e w i d e l y a c c e p t e d u s e of CAD/CAM, d i e m an u f acturing h a s been e x t e n s i v e l y computerized. The p r e s e n t t r e n d s now seem to be ( a ) i m p r o v i n g d i e d e s i g n m e t h o d s b y s i m u l a t i n g and o p t i m i z i n g v a r i o u s f o r m i n g p r o c e s s e s . and ( b ) e s t a b l i s h i n g a n i n t e g r a t e d d e s i g n a n d m a n u f a c t u r i n g a c t i v i t y a l l t h e way from c o n c e p t i o n , d e t a i l e d d e s i g n , and CNC m a c h i n i n g , and quality control. 2.
APPLICATION OF CAD/CAM
I N D I E MAKING
C o n s i d e r i n g a g i v e n metal f o r m i n g p r o c e s s a s a p o t e n t i a l net shape manufacturing oepration, t h e a p p l i c a t i o n of computers i n d e s i g n and m a n u f a c t u r i n g o f f o r m i n g d i e s is i l l u s t r a t e d i n F i g u r e 1 an d involves : t h e e l e c t r o n i c and a u t o m a t i c t r a n s f e r o f 3 D p r o d u c t g e o m e t r y and o t h e r d a t a b e t w e e n d e s i g n and manufacturing (groups, plants, Or companies), t h e c o n v e r s i o n o f t h e a s s e m b l y - r e a d y p a r t g eo m e t r y i n t o a g e c i n e t r y t h a t is ' p r o d u c i b l e " w i t h t h e process u n d e r c o n s i d e r a t i o n . t h e p r e l i m i n a r y d e s i g n of d i e s / m o l d s n e c e s s a r y t o c a r r y o u t t h e n e t shape m a n u € a c t u r i n g process, t h e s m u l a t i o n and o p t i m i z a t i o n o f e a c h p r o c e s s i n g o p e r a t i o n and t h e a s s o c i a t e d tool d e s i g n to r e d u c e p r o c e s s d e v e l o p m e n t a n d t r i a l a n d error, and m a n u f a c t u r i n g o f d i e s and m o l d s by CNC mach i n i n g or b y Electro D i s c h a r g e M a c h i n i n g (EDM) u s i n g C3C m a c h i n e d electrodes.
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, t is c l u i ~ e c A t - r t:.-~ tr.e c o n s i u e r a t i o n of ail net ~ i . u ~r c i . a n ~ t ~ c ~ . i . rpirnoyc e s s e s wouiu be too e x t e n s i v e L G K tr.e sco+ 01 t ~ i s paper. inereiore, tne present U L ~ C ~ S ~is~ rUi i .~t i L t r u co o i e s ariG i.ioks u s e a i n iuetai
d t i t o u b f i r.,any of t i r e . % s n u r d c t L r l n y p r i n c i p l e s a k p i y CG uies moics u s e a i n ~ t ~ . ~e rK O C ~ ~ suet. ~ C S as 4 u a e r m e t a l l u r g y forming, ~ i c&.cinq t i njf2CtlGn i, #oiuinq.
Most c o m p a n i e s who u s e CAD/CAM f o r d i e m a k i n g , u s e t h e i r s y s t e m for g e o m e t r y and d a t a t r a n s f e r , d r a f t i n g , and NC m a c h i n i n g I A l t a n , 1982, A l t a n a n d Billhardt,19831. These a p p l i c a t i o n s o f f e r immediate p r o d u c t i v i t y increases although they use only t h e d e s i g n e r ' s experience and/or empirical equations w i t h o u t much a n a l y s i s ( e x c e p t f o r c r o s s - s e c t i o n a l a r e a s a n d volume c a l c u l a t i o n s ) . Most u s e r s o f f o r d i e m a k i n g u t i l i z e o n l y a small p e r c e n ~CAD/CAM t tage of t h e c a p a b i l i t i e s a v a i l a b l e on s u c h s y s t e m s . T h i s s i t u a t i o n is l a r g e l y d u e to t w o f a c t o r s : (a) t h e systems are still s m e w h a t cumbersome f o r h a n d l i n g t r u e 3D s u r f a c e s e n c o u n t e r e d i n d i e s and m o l d s , a n d ( b ) most users d o n o t h a v e a d e q u a t e t r a i n i n g or b a c k g r o u n d i n d e s c r i p t i v e g e o m e t r y to p e r c e i v e and c o n s t r u c t c o m p l e x s u r f a c e s .
~o:,'inb
CAD/CAM s y s t e m are b e i n g u s e d t o d a y i n t h e metal f o r m i n g i n d u s t r y . These have t h e t r u e 3 D s u r f a c e , a n d i n some cases, e v e n s o l i d g e o m e t r y r e p r e s e n t a t i o n c a p a b i l i t y a s w e l l as modules f o r I~..F ~ ~ ~ s ~ i i or~ a ~l e s~ +nc t i nolcs, o n ~ i materials e p a r a m e t r i c d e s i g n , and g e n e r a t i n g NC c u t t e r p a t h s , an(r V ~ L ~ U U iqletr.ous S or C l t r. la nL ra c c ure n a v e Deen 01smany O t h e r f e a t u r e s . A l i s t o f CAD/CAM s y s t e m s most ~ u ~ e~ arA r i tcf i r . a v e r y cG,..prel.erisive y ~ ~ i i c a t i ~ n s . commonly u s e d i n the d i e a n d mold making i n d u s t r y is i L p f i = e , ,3YAl ~ r i t i i y ,d i e s nay or ciass1tiea D a S e O g i v e n i n F i g u r e 2 [ A l t a n and Oh, 1 9 8 4 1 . -11 ,L ui. e t T I C z c ~ c u r e r , s b r r a c e i ty , a p p i i c u t i o n d1.c ,..at t r i ~ b C d . . a d 4 8 ~ ni w r u L a c t u r i n s recnnlques An i m m e d i a t e and s i g n i f i c a n t q u e s t i o n f a c e d by a d i e ir.cAuuh ~ d 5 ~ i r . 5colc , O K fioc r.odoing, c02y m i l l i n 5 O K a n d mold m a k e r i n t e r e s t e d i n CAD/CAM is w h a t s y s t e m tLrTriia,, oi& t ~ t c t r o~ i s c n d r t , e . , , a c hininq ( t u i l ) a n u to p u r c h a s e . O b v i o u s l y , t h e r e is n o u n i q u e a n s w e r L1.C . . & ~ ~ i r . i i a , of GI+ c d v i t i e s o i r e c t l y K K O a ~ le sceei s i n c e c o n d i t i o n s v a r y from o n e company to a n o t h e r . o r ot LL!. e l ~ ~ t r w i s . i i r t t n a c o d ~ i r i d t i o nof t h e s e However, t h e f o l l o w i n g f a c t o r s ( n o t n e c e s s a r i l y i n ttL..r.iji.es is - ~ e ( r LOT Iianuidcturin., ales dt a order o € s i g n i f i c a n c e ) m u s t b e c o n s i d e r e d : r t c u c e i coaL rtr& w l t f i d c c e p t c r o r e L e a C t i n e s . L ~ S C U ~ n~e W re aISG
A l a r g e number o f
.
Annals of the CIRP, Vol. 36/2/1987
455
S u p p o r t and m a i n t e n a n c e f o r b o t h s o f t w a r e and h a r d w a r e m u s t be a v a i l a b l e , e s p e c l a l l y i f t h e p u r c h a s i n g company d o e s n o t h a v e e x t e n s i v e i n house computer e x p e r t i s e . T h e CAD/CAM s y s t e m m u s t be c a p a b l e O f Z D d r a f t i n g with dimensions, t o l e r a n c i n g and t e x t , a s w e l l a s 3D g e o m e t r y r e p r e s e n t a t i o n ( w i r e f r a m e and s u r f a c e ) and NC c u t t e r p a t h generation. F o r p r e d i c t i n g m a t e r i a l f l o w and t e m p e r a t u r e s a n d f o r c o n d u c t i n g s t r e s s a n a l y s i s on t h e d i e s p r o d u c t s , i t is n e c e s s a r y t o u s e t h e F i n i t e ( F E M ) or F i n i t e D i f f e r e n c e E l e m e n t Method Method (FDM) b a s e d c o m p u t e r c o d e s . For t h i s p u r p o s e , s o f t w a r e m o d u l e s are r e q u i r e d t h a t c a n ( 1 ) g e n e r a t e a mesh ( p r e - p r o c e s s i n g ) and (2) display the r e s u l t s of t h e a n a l y s i s f o r easy i n t e r p r e t a t i o n by the user (postprocessing). OK
The s o f t w a r e s h o u l d u s e s t a n d a r d o p e r a t i n g s y s t e m s and t e r m i n a l s , s i n c e t h e c o m p u t e r s may b e u s e d from t i m e to time f o r c o m p u t a t i o n s u c h a s FEM a n a l y s i s , o t h e r t h a n d e s i g n i n g and NC machlning of d i e s . a p r a c t i c a l CAD/CAM s y s t e m m u s t b e a b l e to c o m m u n i c a t e w i t h o t h e r CAD/CAM s y s t e m s f o r t h e purpose of e l e c t r o n i c d a t a and geometry transfer. O f t e n d r a w i n g s and o t h e r p a r t i n f o r m a t i o n are t r a n s f e r r e d " e l e c t r o n i c a l l y " f r o m o n e c o m p a n y ' s CAD/CAM s y s t e m t o a n o t h e r company or to a n o t h e r l o c a t i o n of t h e same company. T h u s , n e u t r a l f o r m a t s s u c h as IGES (Initial Graphics Exchange S p e c i f i c a t i o n ) GDS ( G r a f i s c h e s Kern S y s t e m ) , or V D A ( V e r b a n d D e u t s c h e r A u t o m o b i l h e r s t e l l e r ) must be a v a i l a b l e [ L a n g e and KOrner. 1 9 8 5 1 . O f t e n t h e I u s t i f i c a t i o n to p u r c h a s e a is b a s e d o n :
CAD/CAM
system
0
I m p r o v e d c o m m u n i c a t i o n b e t w e e n d e s i g n and m a n u f a c t u r i n g a n d / o r b e t w e e n c u s t o m e r and s u p p l i e r . Data are t r a n s f e r r e d v i a telephone l i n e s , t a p e s , O r disks. AS a r e s u l t , errors i n c o m m u n i c a t i o n a r e reduced.
o
R e d u c t i o n i n l e a d time. A l t h o u g h t h i s f a c t o r is u s u a l l y d i f f i c u l t to q u a n t i f y , i t may d e t e r m i n e w h e t h e r a n o r d e r w i l l b e r e c e i v e d or n o t .
0
I n t e g r i t y of data. Errors i n d e s i g n and i n t e r p r e t a t i o n b y d i f f e r e n t d e s i g n e r s are r e d u c e d or eliminated, s i n c e geometry c a n be c a r e f u l l y e x a m i n e d by zooming or d i s p l a y i n g d i m e n s i o n s .
3.
APPLICATION
OF
EXPERT SYSTEMS FOR IHITIAL PART
AND D I E DESIGN
c a n be c o n s i d e r e d a s tools for a u t o W h i l e CAD/CAM matic p r e p a r a t i o n o f d i e d r a w i n g s and NC c u t t e r p a t h (CAE) includes programs. Computer Aided E n g i n e e r i n g t h e p r e l i m i n a r y d e s i g n as w e l l as a n a l y s i s f o r optimum d i e d e s i g n . T h u s , CAE i n metal f o n n i n g i n c l u d e s t h e u s e of b o t h E x p e r t S y s t e m s and p r o c e s s simulation. T h e a p p l i c a t i o n o f E x p e r t S y s t e m s i n metal f o r m i n g is a r e l a t i v e l y new r e s e a r c h a c t i v i t y . A s seen i n F i g u r e 1, e x c e l l e n t a p p l i c a t i o n s f o r t h i s m e t h o d o l o g y a r e in: ( a ) d e s i g n i n g f o r p r o d u c i b i l i t y by a g i v e n p r o c e s s , and ( b ) t h e i n i t i a l d e s i g n o f t h e d i e s p r i o r to optimization v i a process simulation. An e x a m p l e f o r t h e f i r s t case is g i v e n i n F i g u r e s 3 a n d 4 f o r a r i b web t y p e f o r g i n g w h e r e t h e f o r g i n g design, s t a r t i n g w i t h t h e geometry o f t h e m a c h i n e d is b e i n g a u t o m a t e d b y and a s s e m b l y r e a d y p a r t , d e v e l o p i n g a n E x p e r t S y s t e m [Tang e t a l . . 1 9 8 5 ) . I n d e v e l o p i n g t h i s s y s t e m , t h e f o r g i n g d e s i g n know-how is c o m p i l e d i n a s t r u c t u r e d and s y s t e m a t i c f a s h i o n . I n a d d i t i o n , t h e E x p e r t System a l s o p r o v i d e s t h e e x p l a n a t i o n o n how t h e d e s i g n g u i d e l i n e s a r e s e l e c t e d and a p p l i e d . I n o r d e r to s i m p l i f y t h e geometry manipulation, t h e d e s i g n of f o r g i n g s is d o n e by c o n s i d e r i n g s e l e c t e d p a r t s e c t i o n s as s e e n i n F i g u r e 3. T h e s e c t i o n g e o m e t r i e s a r e m o d i f i e d to make a f o r g i n g from a machined p a r t , using design rules. The d e s i g n f e a t u r e s t h a t a r e e s t a b l i s h e d and/or modified include: the parting l i n e , the forging p l a n e t h e f i n i s h i n g a l l o w a n c e , t h e web t h i c k n e s s , t h e r i b w i d t h , t h e d r a f t a n g l e , and t h e c o r n e r and f i l l e t radii. The m p o r t a n t f a c t o r s a f f e c t i n g t h e d e s i g n of t h e f o r g i n g s are: t y p e of forging, (precision, b l o c k e r , or c o n v e n t i o n a l ) , f o r g i n g m a t e r i a l , f o r g i n g e q u i p m e n t , part c o m p l e x i t y , p r o d u c t i o n l o t s i z e , and forging temperatures.
s1c;i:ar d e v e l o p o e n t bias c o n c e n t r a t e d on round : o r y i n c ; s and was e x t e n d e d t o e s t m a t e c o s t s of p r o d u c t i o n [ T r c h c l r w i t c h , 19851. k.
i x ; ) e r t S y s t e n s :re a l s o b e i n g G e V k i o [ ; e d for o f s i g n of ; , r c : i o r n i n y or o l o c k e r d i e s in f o r g i n g w i t h f l a s h e n d for developinq tt.e E o r g i n g sequence in cold forging without flash. 0. p r o t o t y p e s y s t e m c a l l e d RID ( B l o c K e r I n i t l a 1 3 e s i g n ) e x p r e s s e s a rib-web c r o s s web t h i c m e s s . s e c t i o n i n t e r m s of r i n n e l g n t / v l d t h , c r a f t a n g l e , c o r n e r and f i l l e t r a d i u s a s s e e n i n Usincj s t o r e d r u l e s , :he T r o q r a c m o d i f i e s Figure 5 . t h e s e geometric v a l u e s t o come u s w i t t : an i n i t i a l S l o c r t e r o r p r e f o r m d e s i s n [ V e n u r i e t a l . , 1 3 8 6 1 . An FOPWEX, is a b l e t o a u t a n a t i c a l l y E x p e r t System. d e s i g n t h e forming sequence f o r 3 u l t i - s t a g e cold f o r q i n g of p a r t s w i t b . r e l a t i v e l y s i m p l e q e o m e t r i e s s u c h a s t h o s e F r o d u c e d by u p s e t t i n g and f o r w a r d et al., e x t r u s i o n operations Figure 6 [Sevenler 19C71. ?he system n e e d s f u r t h e r development to h a n d l e h o l l o w p a r t s formed by b a c k w a r o c a n e x t r u s i o n o p e r a t i o n s and is, i n p r i n c i p l e . s i a i l a r to s y s t e n s d e v e l o y e d e a r l i e r i n Germany [ R e b k o l z , 1 3 2 5 1 , f n q l a n d [ G O k l e r e t a l . , 1931). and I t a l y [ E a r i a n i an2 K n l q h t . i9851. 2 e c e n t l y a r e s e a r c n s t u u y was c o m p l e t e d On t h e d e v e l o p w 2 n t of an E x p e r t S y s t e m f o r e s t a b l l s n i n q t h e f o m i n y s e j u e n c e i n deb: d r a w i n g of a x l s y m m e t r i c s h e e t .neCal p d r t S LEshel e t a l . , 19861. T h l S SyStei:l rule-uased p r o t o t y p a p p e a r s t o be t h e rnos: a d v a n c e d process sequence a v a i l a b l e to a a t e f o r d e s i y n i n r j :he for G e e p a r a w n rouad p a r t s . 4.
CCKP3TER AIDE!:
TROCESS MODELIIIG FOR G I 2 DESIGLl
The m a i n o b ] e c t l v e s of p r o c e s s !?Odeling a r e to ( a ) i e t e r x l n e w h e t h e r t h e selected f o r m l n g p r o c e s s can p r o d u c e a g i v e n p a r t a s d e f i n e d 5.1 c j r o n e t r y and a a t e r i a l . ( L ) & e d i c t and a v o i d d e f e c t € o r n a t i o n , and ( c ) reduce p r o c e s s d e v e l o p m e n t and d i e r l e s i q n time and c o s t s . T h u s , as s e e n i n F i q u r e 1, t h e i n i t i a l d i e d e s i g n s u c ~ ~ e s t eby d e x p e r i e n c e c a n be v e r f i e d 5" simulating m e t a l flow throughout the f0rmlnq Jperation. T h u s , f o r m i n q e x p e r i m e n t s c a n be r u n on a c o m p u t e r and t h e r e s u l t s c a n b e d i s p l a y e d o n a graphics terminal. If the siaulatlon indicates that o r If t h e selected d l e d e s l q n does n o t f i l l t h e d i e . too :nuch m a t e r i a l w a s t e d , t h e n a n o t h e r d i e d e s i g n c a n be S e l e c t e d and t h e s i a u l a t l o n or " e x c e r i n e n t " c a n he r e p e a t e d and d i e d e s i g n and p r o c e s s c o n d l t l o n s c a n be optimized. AS a r e s u l t , c o s t l y a n d time c o n s u m i n g p r o c e s s d e v e l o p m e n t t r i a l s are a v o i d e d a n d p r o d u c t i o n e q u i p m e n t is n o t t i e d up f o r a e v e l o p i n g t h e f o r m i n g technique for a given p a r t . I n o r d e r to m o d e l or s i m u l a t e a f o r m i n g p r o c e s s , is n e c e s s a r y to h a v e :
a)
a m a t h e m a t i c a l model o f t h e p r o c e s s t h a t r e a l i s t i c a l l y represents the physical occur during the process,
b)
it
r e l i a b l e d a t a on t h e w o r k p i e c e a n d a s w e l l a s on m e c h a n i c a l , t h e r m a l boundary c o n d i t i o n s .
phenomena
that
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T h e a v a i l a b i l i t y and r e l i a b i l i t y o f i n p u t d a t a i n t o a p r o c e s s model is e x t r e m e l y important s i n c e it d i r e c t l y i n f l u e n c e s t h e a c c u r a c y and r e l i a b i l i t y o f t h e p r e d i c t i o n s , e v e n i f t h e model c a n be c o n s i d e r e d t o be m a t h e m a t i c a l l y c o r r e c t and r e l i a b l e . The t y p e of input data necessary for s i m u l a t l n g forming p r o c e s s e s c a n be s u m m a r i z e d a s f o l l o w s :
a)
b e h a v i o u r of m a t e r i a l s u n d e r f o r m i n g c o n d i t i o n s . (1) c o n s t i t u t i v e This information includes: e q u a t i o n s i n s h e e t , b l l l e t , or com~actedpowder p r e f o r m , ( 2 ) t h e r m a l and p h y s i c a l p r o p e r t i e s of t h e w o r r p l e c e a n d d i e m a t e r i a l s a t f o r m i n g tenperarures, (3) formaoillty data, and (41 relationsnips between processing condltlons, m i c r o s t r u c t u r e s and p r o p e r t i e s .
bl
c h a r a c t e r i z a t i o n of c o n d i t i o n s a t d i e - m a t e r i a l i n t e r f a c e . T h i s i n c l u d e s f r i c t i o n and l u b r i cation, neat transfer coefficient, the relations h i p s between p r o c e s s c o n d i t i o n s and s u r f a c e f i n i s h and t o l e r a n c e s .
C)
d i e and m a c h i n e r e l a t e d i n f o r m a t i o n . T h i s i n f o r (11 d i e m a t e r i a l s a n d t h e i r m a t i o n c o n s i s t s of n e c h a n i c a l and t h e r m a l p r o p e r t i e s , ( 2 ) d i e g e o ( 3 ) r a t e o f metal f l o w a s d e t e r m i n e d m e t r y , and b y t h e d i e s and t h e m a c h i n e u s e d .
I n c o n s i d e r i n g p r o c e s s m o d e l i n g and a l e d e s i g n f o r metal f o r m i n g , it is a p p r o p r l a t e to o b s e r v e t h e d i f f e r e n c e s b e t w e e n s h e e t and m a s s i v e or Dulk-fOrming the processes. I n both c a s e s , t h e s u r f a c e s of
d e f o r m i n g m a t e r i a l a n d t h e d i e s a r e i n c o n t a c t , and f r i c t i o n b e t w e e n them h a s a m a j o r i n f l u e n c e o n t h e process. However, o t h e r differences in load. stresses, and s p r i n g b a c k influence d e s i g n and tolerances.
The c o d e PLADiYI ( P l a s t i c Deformation Analysis) d e v e l o p e d i n S t u t t g a r t ILanqe and Y o r n e r , 19851 h a s o e e n a p p l i e d to a v a r i e t y of f o r p i n g p r o c e s s e s and is being f u r t h e r developed. 8.n e x a i ~ p l e o b t a i n e d w i t h PLADP.PI is shown i n F i g u r e 7.
I n m a s s i v e f o r m i n g , t h e i n p u t m a t e r i a l is i n b i l l e t , r o d or s l a b f o r m , a n d a c o n s i d e r a b l e i n c r e a s e i n t h e s u r f a c e to volume r a t i o and c h a n g e s i n c r o s s - s e c t i o n s take place. T h e p o r t i o n of t h e w o r k p i e c e u n d e r g o i n g p e r m a n e n t p l a s t i c d e f o r m a t i o n is g e n e r a l l y much l a r g e r than t h e portion undergoing elastic deforAS a result, elastic recovery a f t e r mation. is n e g l i g i b l e but the deformation deformation stresses a r e much h i g h e r , t h r e e to ten times, t h a n t h o s e Observed i n s h e e t m e t a l forming.
I n t h e United S t a t e s , t h e fundamental s t u d i e s of t h e l a s t d e c a d e c o n d u c t e d a t Berkele:.' I K o b a y a s h i , 1 9 t 5 1 k a v e b e e n t r a n s l a t e d i n t o p r a c t i c a l c o m p u t e r codes by Dattelle [Oh and P . l t a n , 19851 and Marc I i n a l y s i s [Rebello,1906). I n a d d i t i o n , t h e code developed a t t h e Lawrence L i v e r m o r e L a b o r a t o r y f o r i n v e s t i q a t i n g i n p d c t tyFe phenonena h a s been a p p l i e d to s l m u l a t l o n of f o r g i n g p r o c e s s e s [ F l o w e r a n d H a l l q u l s t , 15861. T h e s e l a s t three c o d e s c a n h a n d l e n o n - l s o t h e c x a l f o r g i n g s i m u l a t i o n s p r o v i a e d v a l u e s for h e a t t r a n s f e r c o e f f i c i e n t s and o t h e r t h e r a a l c o n s t a n t s e x i s t as input.
I n s h e e t f o r m i n g , a s h e e t b l a n k is p l a s t i c a l l y object w i t h o u t deformed i n t o a three-dimensional s i g n i f i c a n t changes i n s h e e t thickness. I n some cases, t h e magnitude o f permanent p l a s t i c and recoverable elastic deformations a r e comparable; t h e r e f o r e , e l a s t i c r e c o v e r y or s p r i n g b a c k may be significant. T h u s , i t is a p p r o p r i a t e to c o n s i d e r p r o c e s s m o d e l i n g and d i e d e s i g n s e p a r a t e l y f o r s h e e t and m a s s i v e forming
.
5,
PROCESS SIMULATION FOR DESIGNING DIES FOR MASSIVE FORMING
During t h e l a s t d e c a d e , computer s i m u l a t i o n h a s been i n c r e a s i n g l y a p p l i e d t o m e t a l f o r m i n g processes u s i n g v a r i o u s methods o f p l a s t i c i t y w i t h v a r y i n g d e g r e e s of m a t h e m a t i c a l c o m p l e x i t y and r e l i a b i l i t y . The methods u p p e r bound o f a n a l y s i s used i n c l u d e slab method, m e t h o d , and f i n a l l y , t h e F i n i t e E l e m e n t Method, w h i c h i s now b e i n g f u r t h e r d e v e l o p e d i n v a r i o u s l a b o r a tories a r o u n d t h e world. While i n i t i a l a p p l i c a t i o n s o f s i m u l a t i o n were C o n c e n t r a t e d o n r o l l i n g , e x t r u s i o n a n d d r a w i n g , r e c e n t r e s e a r c h is h e a v i l y c o n c e n t r a t e d on forging [ P i t t m a n e t a l . , 1 9 8 4 , Boer a n d J o v a n e . 19841. T h e u p p e r - b o u n d e l e m e n t a l t e c h n i q u e , UBET, d e v e l o p e d b y B r a m l e y and h i s c o - w o r k e r s , c a n be u s e d to p r e d i c t f o r g i n g l o a d s , m e t a l f l o w , and l o c a l d i e p r e s s u r e i n a s s i s t i n g t h e d e s i g n of f o r g i n g d i e s [ G h o r r i a l et a l . 19851 a n d [ B r a m l e y , 1 9 8 7 1 . T h i s technlque needs r e l a t i v e l y m a l l c o m p u t i n g p o w e r and is s u f f i c i e n t l y a c c u r a t e i n p r e d i c t i n g t h e forging load v e r s u s d i e d i s p l a c e m e n t , and d i e f i l l f o r s i m p l i f i e d g e o m e t r i e s . However, i n g e n e r a l , i t is n o t a s a c c u r a t e a s t h e FEM-based p r o c e s s m o d e l s , e s p e c i a l l y i f the effects o f f i l l e t and c o r n e r r a d i i a r e i n v e s t i g a t e d . S e v e r a l FEM-based c o m p u t e r p r o g r a m s f o r s i m u l a t i o n of m a s s i v e f o r m i n g p r o c e s s e s are b e i n g d e v e l o p e d a r o u n d t h e w o r l d , i n p a r t i c u l a r , i n Swansea a n d Birmingham S t u t t g a r t , Aachen, and Hannover i n i n t h e U.K., Germany, K y o t o I n s t i t u t e o f T e c h n o l o g y and Kobe U n i v e r s i t y i n J a p a n , and C o r n e l l , B e r k e l e y , Marc Analysis, Battelle-Columbus, and Lawrence Livermore L a b o r a t o r y i n t h e United S t a t e s . A good o v e r v i e w of t h e s e d e v e l o p m e n t s is g i v e n i n t h e p r o c e e d i n g s o f t w o recent c o n f e r e n c e s [ L a n g e , 1 9 8 5 , P i t t m a n e t a l . , 19851.
i n Aachen, a h y b r i d method u s i n g b o t h t h e This FEM and t h e e l e m e n t a r y t h e o r y was d e v e l o p e d . axisymmetric and method s i m u l a t e s two-dimensional, p l a n e S t r a i n f o r g i n g o p e r a t i o n s w i t h r e a s o n a b l e accur a c y and w i t h o u t r e q u i r i n g v e r y l a r g e c o m p u t i n g power [ K o n i g e t a l . , 1 9 8 5 , Konig and Hofmann, 19861 This to f o r g i n g h y b r i d t e c h n i q u e h a s a l r e a d y been a p p l i e d of v a r i o u s g e o m e t r i e s , a s well a s to c o l d e x t r u s i o n of spur g e a r s . The r e s u l t s a p p e a r to be a d e q u a t e a s b o u n d a r y c o n d i t i o n s f o r e l a s t i c FEM a n a l y s i s o f t h e tool stresses a n d f o r e s t i m a t i n g d i e w e a r i n h o t forging A t t h e RWTH
AL?ID ( i i n a l y s i s ot L a r g e r l a s t i c I n c r e n e n t a l Deformat i o n ) was d e v e l o j e d j o i n t l y by i m t t e l l e and the U n i v e r s i t y of C a l i f o r n i a - C e r k e l e y w i t h su-,sort fron t 5 e A ~ K Force. it is now b e i n g u s e d s y v a r i o u s i o r g i n g and f o r m i n g c o m p a n i e s . An e x a m p l e o b t a l n e d w i t h t h e i s o t h e r n a l v e r s i o n Of ALPID is shown in Figur2 8 . "his f i g u r e i l l u s t r a t e s the d e f o r m t i o n The pattern in isothermal forqing a titaniun disk. i n a t e r i a l n e a r t h e f l a s h or p a r t i n q l i n e r e q u i r e s a g r e a t e r d e g r e e o f f r e e d o n t o a c c o n m o d a t e t h e coiny l i c a t e d flow p a t t e r n near t h e f l a s h zone. Therefore, t w o r e m e 5 h i n g o p e r a t i o n s w e r e n e c e s s a r y to a c h i e v e t h e f i n a l d e f o r m a t i o n shown i n F i g u r e 9 . T h r o u g h r e n e s h i n g ! a ) a new n e s h is a s s i q n e d t o accommodate t h e complex d e f o r m a t i o n T a t t e r n , and h ) t h e s t r a i n d i s t r i b u t i o n is l n t e r n o l a t e d f r o m t h e old mesh 3 n t o t h e new n e s h . T h i s r e n e s h i n q n r o c e d u r e is e x t r e m e l y i m p o r t a n t for s i m u l z t i n q F r a c t i c a l f o r g i n g o p e r a t i o n s w h e r e 1arc;e d e f o r m a t i o n s a r e p r e s e n t and t h e p r o p e r t i e s of t h e d e f o m i n s m a t e r i a l a r e d e t e r niined by t h e amount of d e f o r m a t i o n lmposecj o n t h e forged p a r t . P.n e x a m p l e o f t n e n o n - i s o t h e r m a l ALPID s l n u l a t l o n is shown i n F i g u r e 9 f o r u p s e t t i n g a c y l i n d e r . In t h i s case, t n e 1C20 s t e e l b i i l e t was r i e a t e d to 1232C m i l e t h e l n t l d l d i e tel:lyeratuKe WdS 204C. T;ie p r o c e s s V Z S consicered t o tarce p l a c e i n t h r e e u i s t i n c t ; i n a s e s where u i f f e r e n t h e a t t r a n s f e r c o e f f i c i e n t s a t t h e . x a t e r i a L - u i e i n t e r f a c e were assuaed i a ) t h e h e a t e d k l i i e t is p l a c e d tiFon t h e lover d i e a n d r e s t s for s i x s e c o n d s , b)
u p s e t t i n g s t a r t s and is s t o p p e e a t 67 p e r c e n t reu u c t i o n i n h e i g h t , 1.e. 1 . 5 s e c o n d s l a t e r , and
c)
t h e u p s e t b i l l e t r e m a i n s o n c h e lower h i e €or t h r e e secGnCis a f t e r tile to? a l e is removec.
rA'i~e p r e d i c t i o n s of
t e n p e r e t u r e s . l o a d , and n e t a l f l o k r e coinprea w i t h e x p e r l n e n t a i c a t h and the agreem e n t was s u i t e s a t i s f a c t o r y a 1 t h o r ; y h t h e r e s u l t s assumed h e a t d e p e n d e d c o n s i d e r a S l y on t h e v a l u e s of transfer coefficients. -m. * ~
i n g e n e r a l , ZEM p r o g r a i i s r e q u i r e a s i n p u t d a t a : 0
I n H a n o v e r . t h e r e c e n t l y d e v e l o p e d FEM p r o g r a m , FARM ( F i n i t e E l e m e n t A n a l y s i s o f R i g i d P l a s t i c Metal F o r m i n g ) h a s b e e n u s e d to e x p l o r e t h e o p t i m i z a t i o n o f d i e l i f e b y e x t e n d i n g t h e e x i s t i n g c o d e to c o n s i d e r The h e a t t r a n s f e r b e t w e e n t h e d i e s and t h e f o r g i n g . r e s u l t s of t h i s s t u d y i l l u s t r a t e d t h a t t h e d i e s are s u b j e c t to c o m p l e x t h e r m a l and m e c h a n i c a l s t r e s s e s a n d it is p o s s i b l e to u n p r o v e d i e l i f e by m o d i f y i n g t h e r h e r m a l c o n d i t i o n s i n t h e d i e s and by r e d u c i n g t h e t h e r m a l stress g r a d i e n t s [Ma and Weiss, 1 9 8 6 1 . T h e FEM m e t h o d is a l s o u s e d i n a j o i n t i n v e s t i g a t i o n b e t w e e n ARBED R e s e a r c h a n d t h e U n i v e r s i t y o f L i e g e [Groaer e t a l , 19851 for a x i s y m m e t r i c u p s e t t i n g a n d e x t r u s i o n and f o r p l a n e s t r a i n - r o l l i n g o p e r a t i o n s . T h e r e s u l t s a p p e a r to i n d i c a t e t h a t t h e method b e i n g d e v e l o p e d g i v e s good r e s u l t s a n d h a s p o t e n t i a l f o r f u t u r e expansion.
movement.
e
w o r k p i e c e g e o n e t r y by e l e m e n t s and n o d a l p o i n t s ,
o
n a t e r i a l p r o p e r t i e s . 1.e. f l o w s t r e s s i n f u n c t i o n o f t e m p e r a t u r e , s t r a i n r a t e and s t r a i n a s well a s t h e r m a l p r o p e r t i e s i n f u n c t i o n of t e m F P r a t u r e , bnd
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n e a t t r a n s f e r c o e f f i c i e n t in f u n c t i o n of pressure.
.
.
uie data, 1.e. d i e g e o a e t r j ' , die f r i c t i o n a t die-material interface,
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i o r g i n y load v e r s u s d i e s t r o k e .
o
i . 1 a t e r i a l f l o w i n form o f modal v e l o c i t i e s and g r i d d i s t o r t i o n , and
0
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of: Stress, s t r a i n ,
s t r a i n - r a t e and
L ? m k f e rd t U KC'.
T h u s , iT1.1 p r o g r a ~ r ;o f f e r v e r y u s e f u l i n f o r m a t i o n f o r g r e u i c t i n g p r o > e c t i e s , SOUndneSS of formed p r o d u c t s , and d i e f i l l i n g . i : f t n o S s o t h e r t h a n FEN are a l s o e x t r e n e l y u s e f u l i n p r e d i c t i n g t h e p r o c e s s v a r i a c l e s and d e s i g n l n q 6 i e s f o r a l a r g e number of o p e r a t i o n s . For e x a m p l e , t h e C m p u t e r AiGed E n g i n e e r i n q S y s t e n , d e e l o p e c a t t h e I:arsaw U n i v e r s i t : i of Technology t a k e s i n t o a c c o u n t t h e tool l o a d i n g . t h e f r a c t c r e o f t h e f o r n e d r , a t e r i a l
457
i n che c e s l o n o u t s l u e t b e d e f o r n a t i o n zone and t h e d u c t i l e f r a c t u r e in the deformation zone lh'arciniak. A c o m p r e h e n s i v e CAD/CAV s y s t e m for practical 19E6l. d i e d e s i g n a n d m a n u f a c t u r l n g i n f o r g i n g 1s l n o p e r a tion i n Japan [ C o t o h , 19251 a n d i s p l a n n e d in Eelqium [ K r u t b , 19371. I n a d d i t i o n . a l a r g e number o f computer a i d e d n o d e l s bave been developed for the a n a l y s i s o f o t h e r n a s s i v e f o r m l n y o p e r a t i o n s , s u c h as s h a F e and r i n g r o l l i n g . e x t r u s l o n . and i r o n i n g . 6,
PROCESS SIE!ULATIOll FOP SHEET NETAL FOPI.!It:C
S i m u l a t i o n of s h e e t f o r m i n g p r o c e s s e s h a s b e e n t h e s u b j e c t o f a l a r y e number of s t u d i e s t h r o u g h o u t t h e worli. >lost o f t h e models d e v e l o p e d so f a r d e a l w i t h a x i s y m m e t r i c and p l a n s t r a l n d e f o r m a t i o n c o n d i t i o n s . Conpurer prograns f o r slinulation brake bending, roll bending, and punch S t r e t c h i n g rubber tormlng. nave been s u c c e s s f u l l y developed [Hagpal e t a l . , i 5 8 2 , Uh a n d K o b a y a s l l l , i9221. I n a l l t h e s e prociata o n s h e e t t h i c k n e s s , tool g e o m e t r y , grass, . a a t e r i a l f l o w s t r e s s , a n d f r i c t i o n a r e u s e d to p r e t i i c t , s t e p oy s t e p , t h e i n s t a n t a n e o u s s h e e t g e o m e t r y , tile s t r a i n s i n t h e s h e e t , a n d t h e l o a c ' versus stroke A s a n e x a m p l e , t h e r e s u l t s €or b r a k e b e n d i n g curve. are i l l u s t r a t e d i n f i g u r e 10. In t h i s figure, the h c e s s r a n a n d t h e b e n t s h e e t a r e shown s c h e m a t i c a l l y f o r v a r i o u s s t r o k e p o s i t i o n s during t h e bending operation. i?ecently, t h i s w o r k h a s b e e n e x p a n d e d to s i m u l a t e t h e d e e p drawing o f round c u p s o f v a r y i n g cross s e c t i o n s [ V e m u r i e t a l . , 1 9 2 6 1 . c o m p u t e r code, c a l l e d SHEETS, was r e c e n t l y a p p l i e d t o s i m u l a t e p l a n s t r a i n and a x i s y m m e t r i c s h e e t form-
; i
ing
under production c o n d i t i o n s [Lee and Forth. T h e s c h e m a t i c o u t l i n e o f t h e m o d u l e s of t h i s is s e e n i n F i g u r e 11. T h i s i n t e g r a t e d code :rogram is c a p a b l e o f p r o v i d i n g a n i n s t a n t a n e o u s g r a p h i c r e p r e s e n t a t i o n of t h e degree o f s u c c e s s or f a i l u r e i n t h e formability of sheet n e t a l p a r t s at the design s t a g e . Key e l e m e n t s o f t h e a n a l y s i s p r o g r a m s c o n s i s t o f c o n s t i t u t i v e e q u a t i o n s , forming l i m i t diagrams, and f i n i t e element a n a l y s i s programs.
i9131.
The forming of axisymnetric s h e e t metal p a r t s can also ue 6 n a l y z a c ; u s i n g a p r o g r a m , c a l i e d AXIFORH [Gerdren, l9341. T h i s p r o g r a m is u a s e d o n l a r g e d e f o r x a c i o n and l a r g e - s t r a l n t h e o r y of p l a s t i c i t y . It includes combinations of s t r e t c h i n g , bending and d r a w i n g modes o f d e f o m a t i o n . thickness variations, s t r a i n h a r d e n i n g and m u l t i p l e stages o f forming, capabilities f o r predlCting residual stresses, o r i g i n a l blanK s i z e and f o r m i n g l o a d . Computer a i d e d d e s i g n and s i m u l a t i o n f o r forming o f non-symmetric s h e e t netal parts have also been attemGted with consideraole success. In one s t u d y . c h 7 p u t e r l z e d s l i p l i n e f i e l d m e t h o d h a s b e e n u s e d to a n a l y z e t h e stresses, p r e d i c t t h e m a t e r i a l f l o w , a n d estimate t h e i n i t i a l b l a n k g e o m e t r y [ G l o e c k l and L a n y e , 13831. More r e c e n t l y , a f i n i t e e l e m e n t p r o c e U u r e h a s Deen d e v e l o p e d f o r m o d e l i n g t h e d r a w i n g p r o c e s s f o r s q u a r e c u b s b a s e d o n f i n i t e s t r a i n formul a t i o n a n d m e m b r a n e t h e o r y [ K o b a y a s h i , 19851. The s h e e t m a t e r i a l was a s s u m e d to b e a n i s o t r o p i c a n d s t r a i n h a r d e n i n g w h i l e Coulomb f r i c t i o n was c o n s i d e r e d a t tool-material i n t e r f a c e . S i m u l a t i o n s were conducted f o r various blank shapes with i d e n t i c a l Good c o r r e l a t i o n s were s u r f a c e a r e a s , Figure 12. found between p r e d i c t e d and measured v a l u e s o f punch l o a d s and o f deformed f l a n g e g e o m e t r i e s . e L ! u l a t i o n o f more c o m p l e x a n d t r u l y 3D s h e e t f o r m i n g o p e r a t i o n s are b e i n g a t t e m p t e d b y n e a r l y a l l a u t o m o t i v e companies around t h e world. Companies such as GM. F o r d , C h r y s l e r , T o y o t a a n d O t h e r s a r e d e v e l o p i n g , o n o n e h a n c . C o m p u t e r I n t e g r a t e d M a n u f a c t u r i n g (CIM) a n d , o n t h e o t h e r h a n d , FEM-based p r o g r a m s f o r t h e simulation o f complex s h e e t forming o p e r a t i o n s [ C r e s t i n a n d Kci,:aters, 1 3 8 6 , Gang a n d T a n g , 1 9 8 5 1 . ; c h i l e c h e CI:.: s y s t e m s are p r o v e n to b e f u n c t i o n a l a n d & r a c t l c a l , t h e 3D s i m u l a t i o n m e t h o d s s t i l l u s e s u p e r conijuters a n d are s t i l l n o t q u i t e i J r a c t i c a l , e x c e p t tor a f e w r e l a t i v e l y s i m F l e cases. 7.
DIE MANUfACl'URING
AND MAINTENANCE
Various die manufacturing techniques, e.g., c a s t i n g , Cold a n d h o t h o o b i n y , c o p y m i l l i n g , CNC n a c h i n i n y , a n d E W l by u s i n g co;y m i l l e d or QJC m a c h i n e d electrOdeSr dre well-Known. I n e a c h s p e c i f i c applicat i o n , d e p e n d i n g upon t h e specific c o n d i t i o n s and t h e t e c h n o l o g y a v a i l a b l e , o n e or more of t h e s e t e c h n i q u e s a r e selected. I n t h e a u t o n o t i v e i n d u s t r y , t h e emphasis i n nanufact u r i n q Of s h e e t f o r m i n g d i e s is o n i n t r o d u c i n g a C m p u t e r I n t e g r a t e d System. Briefly, i n such a
s y s t e m t n e p a r t d e s i g n is e i t h e r u i g i t i z e d from a c l a y m o a e l or o b t a i n e d f r o m a 3D CAD model. After adaing the appropriate peripherial geometric features for b l a n k h o l d i n g a n d c o n t r o l o f t h e m a t e r i a l f l o w , t h e d i e is c a s t u s u a l l y v i a t h e l o s t - € o a m t e c h n i q u e . FOC t h i s purpose, t h e s t y r o f o a i n p a t t e r n s a r e CNC , n a c h i n e d u s i n g t h e g e o m e t r i c d a t a f r o m t h e same p a r t d a t a base. T h e c a s t d i e c a v i t y is CNC m a c h i n e d to final tolerances. The machining marks a r e u s u a l l y r e m o v e d b y hand g r l n d i n g a n d p l i s h i n g . T h e t r e n d is t o u s e f i v e - a x i s m a c h i n i n g w h i c h a ) is more e f f i c ient, s i n c e f l a t - e n d m i l l s with l a r g e metal removal c a p a b i l i t y c a n be u s e d , a n d b ) p r o v i d e s a b e t t e r s u r f a c e f i n i s h and r e d u c e s t h e need for surface f i n i s h i n g and p o l i s h i n g IKonig and K o l l i n g , 19861. T h i s l a t t e r o p e r a t i o n is q u i t e l a b o r i n t e n s i v e . Therefore, a u t o m a t i c d i e p o l i s h i n g machines have is beinq r e c e n t l y been introduced. Research c o n d u c t e d f o r d e v e l o p i n g more e f f i c i e n t a n d p r a c t i c a l d i e p o l i s h i n g t e c h n i q u e s [Nakagawa, 19861
.
Dies f o r massive forming without f l a s h , i.e., f o r c o l d a n d warm f o r g i n g , a r e u s u a l l y a x i s y m m e t r i c or n e a r l y so. T h e y a r e u s u a l l y m a c h i n e d b y CNC t u r n i n g non-sysmmetric feaw i t h p o s s i b l e a d d i t i o n a l EDM o f tures. T h e s e u i e s are h i g h l y stressed; t h e r e f o r e , r i n g s 1s t h e d e s i g n of t h e d i e s and t h e s h r i n k - f i t .nost c r i t i c a l from t h e p o i n t o f v i e w o f r e s i s t a n c e t o nechanical tatique. The g r i n d i n g , f i n i s h i n g , and s t r e s s r e l i e f o p e r a t i o n s are c r i t i c a l s t e p s i n manut a c t u r i n g such dies.
I n nanufacturing of dies f o r forging with f l a s h , t h e I n some c a s e s , t r e n d is t o u s e EDM [ K r u t h , 1 9 8 6 1 . e s p e c i a l l y i n m a k i n g l a r g e d i e s , ECM or QK m a c h i n i n g Here t h e may be u s e d a s a r o u g h m a c h i n i n g s t e p . t r e n d is to u s e CAD/CAM s y s t e m s f o r g e n e r a t i n g t h e NC the t a p e i m a g e a n d to m e a s u r e t h e d i m e n s i o n s o f i n a c h i n e d d i e c a v i t y v i a a CMM, u s i n g t h e Same g e o a e t r i c d a t a b a s e for a l l : d e s i q n , CNC m a c h i n i n g ; a n d d i m e n s i o n a l i n s p e c t i o n [ E n g e l i , 19861. I n CNC m a c h i n i n g , t h e t r e n d is to make e x i s t i n g s o f t more u s e r - f r i e n d l y a n d e a s i e r t o l e a r n [i:elbourn. 19841. As in other engineering software packages, a m i g r a t i o n of NC machininq software towards micro c o m p u t e r s a n d e n g i n e e r i n g w o r k s t a t i o n s is o b s e r v e d . I n t e r e s t i n g s o f t w a r e d e v e l o p m e n t s are c a r r i e d o u t to a p p l y s o l i d m o d e l i n g to s i m u l a t i o n a n d v i s u a l i z a t i o n of t h e d i e m a c h i n g o p e r a t i o n [Walsham and Knight, 19851. O b s e r v i n g t h e tool a n d t h e d i e s u r f a c e b e f o r e and a f t e r m a c h i n i n g i n s h a d e d p h o t o the generated l i k e form m a k e s t h e v e r i f i c a t i o n o f c u t t e r paths q u i t e easy.
ware s y s t e m s
T h e u n d e r s t a n d i n g o f d i e f r a c t u r e a n d w e a r is t h e s u b j e c t o f s e v e r a l new i n v e s t i g a t i o n s [ R e i S S , 19861. E x t e n s i v e s t u d i e s o n t h e u s e of s u r f a c e c o a t i n g s a n d t r e a t m e n t s to i n c r e a s e a b r a s i v e d i e wear a r e b e i n q [Meist a n d W e s t h e i d e , conducted around t h e world It appears that 1 9 8 6 , Konig and T r e p p e , 19861. f u n d a m e n t a l k n o w l e d g e o n t h e r e l a t i o n s h i p s of d i e s u r f a c e stresses, t e m p e r a t u r e s , a n d r e l a t i v e m a t e r i a l v e l o c i t i e s are n e c e s s a r y i n Order to f u l l y u n d e r s t a n d t h e p h e n o m e n o n o f d i e wear a n d to p r e d i c t when d i e s h a v e to be m a i n t a i n e d a n d / o r e x c h a n g e d f o r p r e v e n t i v e maintenance purposes. ACKNOKLEDGENENTS T h i s paper h a s b e e n p r e p a r e d w i t h i n p u t f r o m a n u m b e r o f CIRP c o l l e a g u e s a n d o t h e r e x p e r t s . The a u t h o r would l i k e to a r a t e f u l l v acknowledae t h i s a s s i s t a n c e as f o l l o w s : K.
E.
w.
B r a m l e y , CAD of F o r g i n g D i e s Doege, A n a l y s i s o f F o r g i n g a n d R o l l i n g P r o c e s s e s A. K n i g h t , CAD/CAM, S o l i d M o d e l i n g a n d F o r g i n g
Dies K o e n i g , T e c h n o l o g y o f D i e M a c h i n i n g , CAD o f F o r g i n g Dies, S u r f a c e T r e a t m e n t a n d D i e Wear H . Kudo, CAD of D i e s for M a s s i v e F o r m i n g , CAM o f S h e e t Metal Dies b y J a p a n e s e A u t o m o b i l e Manufacturers J . P . K u r t h , CAD/CAM o f F o r g i n g and I n j e c t i o n M o l d i n g Dies K . L a n g e . C l a s s i f i c a t i o n o f Dies. D i e Wear i n C o l d Forging, Analysis of Deformation 2 . M a r c i n i a k , CAD of M a s s i v e a n d S h e e t f o r m i n g processes m I. Nakagawa, V a r i o u s D i e Making and P o l i s h i n g Techniques J . R e i s s n e r , CAD/CAM i n S h e e t Metal F o r m i n g D. B. t i e l b o u r n , CAD/CAM o f Dies a n d A p p l i c a t i o n s i n Foundry
w.
I. a n d C e q e l . Y., Jar.. 1 9 0 2 , D e s i g n a n d Yanu f a c t u r i ng ( CPW/CAf.' ) o f iiot Forging D i e s . J. Applied Y e t a l u o r k i n y , 2, :io. 2 , b. 77. A l t a n , T., und B i i l h a r d t , D. F . , G C t . 1923. A p F l i c a t i o n of CAD/CAM i n E x t r u s i o n A Management G v e r v i e w . L i g h t ?,eta1 Acje, , 24. A l t a n , 'J., C:i. 6. I . a n d Gegel, i i . , :,!eta1 Forming, i 9 3 3 , X e t a l ForminJ: F u n d a m e n t a l s and A+;iications, m e r i c a n S o c i e t y c;€ :,letals, e e t a i s P a r K , cii. A l t a n , T. a n d G h , S. I . , 1 9 8 4 , CA3/CAbi o f T o o l i n y , E q u i p n e n t and P r o c e s s for P l a t i c i i o r i t i n y , P r o c e e d i n g s of t h e 1st I n t e r n a t i o n a l C o n f e r e n c e o n t h e T e c h n o l o g y of P l a s t i c i t y , T o k y o , p. 5 3 1 . C a c i a n i , P. a n d K n i j i h t , i:. A . , 1 9 D 5 , C o c p u t e r A i d e d Cold Forqing P r o c e s s Design: Determination of # a c h i n e S e t t i n g C o n d i t i o n s . A n n a l s of CIRP, V o l . 3 4 , !!o. 1, 245. D r a m l e y , A . f!., C o m p u t e r A i d e d F o r g i n g D e s i g n , p a p e r s u b m i t t e d to CIP? A s s e m b l y . A u g u s c , 1 9 E 7 , t o o e ; ; u o l i c h e c i i n CIR? A n n a l s . roec, C. 2 . a n d J o v a n e , R . , 1 9 2 4 , C o n p u t e r P.ided C e s i g n in Metal F o r m i n g S y s t e m s , A n n a l s of C I R P . L'Ol. 3 3 , IJO. 2 , r,. 4 3 3 . C r e s t i n , J. P . a n d ' C K a t e r s , J. F. ( e d i t o r s ) , 1 9 2 5 S o f t w a r e f o r Dicrete h!anufacturing. P r o c e e d i n q s o f t h e 6 t h I n t e r n a t i o n a l IFIP/IFAC c o n f e r e n c e . PirOLhPiAP 35, P a r i s , ~ u b l i s h e d by :;OCth i l o l l a n d . P n g e l i , it., 192C, COKLI3- e i n e i n t e g r i e r t e CAD/CAM L o s u n g , T e c n n i s c h e R u n a s c h a u , Vol. 2 0 . p. 1 5 6 . E s h e l , c:., J a r a s h , i.!. and J o h n s o n , L., 1 9 0 6 . R u i e E a s e d # o d e l i n g f o r P l a n n i n g A x i s y . m e t r 1 c Deep o r a u i n g , J. I,.ech, L l o r k i n y T e c h n o l o g y , 1 4 , p . 1 . F l o k e r , E . C. a n u H a l l ~ u l s t ,J . , J u l y 1 9 8 6 , F o r g i n g DY Conktiter pays Oft, iimerican b:achinist and Automa tec M a n u f a c t u r i n g C e r d e e n , J.C., ;.:a? 198.4, D e v e l o p n e n t of a C o m p u t e r P r o g r a m - AXIFG.?:.: f o r t h e A n a l y s i s o f F o r m i n g oE A x i s p e t r i c S h e e t .*!eta1 P a r t s , P r o c e e d i n g s of LIAXRC X I I , I . i i c h i g a n T e c h . u n i v e r s i t y , i l o u g h t o n , ?:I, , p. 2 4 3 . C h o b r i a l , i.!. I . , Osman, F. ii., a n d B r a m l e y , A. : I . , 1 9 8 5 , F o r g i n g F l a s h C e s i g n U s i n g WET, P r o c e e d i n g s o f NAMRC-XIIX, P e r k e l e y , C a l i f o r n i a , , p. 151. G l o e c k l , t i . a n d L a n g e , K., # a y 1 9 3 3 , C m p u t e r A i d e d E e s i g n o f t 7 l a n k s for Deep Drawn I r r e g u l a r S h a p e d C o m p o n e n t s , P r o c e e d i n g s o f tIAI.!RC X I , p. 2 4 3 . Goklar. :,I. I . , D e d n , T. A. a n d K n i g h t , h . A . , S e p t e i a b e r 1 9 0 1 , C m p u t e r Aided S e q u e n c e D e s i g n f o r liOt U>Sht F O c S i n y S , T r o c e e d i n g s O f t h e 22nd SITDR C o n f e r e n c e , x a n c h e s t e r , i ~ l a c m l l l a n , L o n d o n , p. 4 5 7 . C o t c n , i?., May, 1 9 8 5 , CAD/CA:< f o r Drop F o r g i n g , J . J a p a n S o c i e t y for T e c h n o l o g y o f P l a s t i c i t y , V. 2 6 ,
f:.ltan,
7 . , 13.S. C c m p ti t e r A i d e d
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