1、N e w T e c h n o l o g i e s i n M a n u f a c t u r i n g T h e C h a l l e n g e o f m a n u f a c t u r i n gTh e n e e d for q u a l i fi e d m a n u fa c tu r i n g e n g i n e e r s h a s n e ve r b e e n g r e a t e r . To m e e t tod a y s ch a l le n g e s , i t i s n e ce s s a r y to g a
2、 i n a b r oa d b a ck g r ou n d i n b oth m a t e r i a l s c i e n ce s , d e s i g n , a n d m a n u fa c tu r in g p r oce s s e s . Con s id e r a b le e m p h a s i s i s a l s o b e in g p l a ce d on com p u te r s c i e n ce s a n d a u tom a t i c con t r ols .Th e m a n u fa c tu r i n g
3、 e n g i n e e r m a s t b e a b l e to v i s u a l i ze th e w h o le p r ob l e m of p r od u ct i on i n th e cor r e c t p e r s p e c t i ve fr om th e b a s i c com p on e n t m a te r i a l s a n d toolin g th r ou g h th e s te p b y s te p op e r a t i on a l p l a n n in g , fin a l a s s
4、e m b l y , i n s p e c t ion , a n d s h i p m e n t .Th e m a n u fa c tu r in g e n g in e e r i s r e s p on s i b le for th e e x p e n d i tu r e of l a r g e s u m s of m on e y for toolin g a n d m a ch i n e r y to k e e p p r od u c t i on on a com p e t i t i ve b a s i s . H e n ot on l
5、y s h ou ld b e fa m i l i a r w i th th e th e or e t i ca l a s p e c t s of fa b r i ca t i on , b u t a l s o m u s t b e a b l e to w or k ou t p r a c t i ca l “b r e a d a n d b u t te r ”p r ob l e m s of th e p r od u c t i on floor .A fe w of th e a r e a s i n w h i ch a m a n u fa c tu r
6、 in g e n g in e e r ca n b e e x p e c te d to w or k a r e in p l a n n i n g p r oce s s l a y ou t s , p l a n t l a y ou t , e q u i p m e n t s p e c i fica t ion , m a te r i a l s p e c i fica t ion , tool d e s ig n , m e th od s d e ve lop m e n t , w or k s ta n d a r d s , va lu e a n a
7、l y s i s , a n d cos t con t r o l .As th e m a n u fa c tu r i n g e n g i n e e r g a in s e x p e r i e n ce , a n d i f h e h a s a h i g h d e g r e e of cr e a t iv i ty a n d in n ova t i ve a b i li t y , h e ca n e x p e c t to b e i n volve d i n th e g e n e r a t i on of m a n u fa c tu
8、 r i n g s y s t e m con ce p t s . H e w i l l a l s o b e in volve d in th e d e ve lop m e n t of n ove l a n d s p e c i a l i ze d e q u i p m e n t , r e s e a r ch i n to th e p h e n om e n a of fa b r i ca t i n g t e ch n o log i e s , a n d m a n u fa ctu r i n g fe a s i b i l i ty s tu
9、d i e s of p r op os e d n e w p r od u c t s .N ot a l l of th e i n n ova t i on s th a t i n cr e a s e e ffi c i e n cy of m a n u fa c tu r e a r e in th e a r e a of m a ch i n e tools , i n s p e c t i on , or a u tom a te d a s s e m b l y p e r s e . In cr e a s i n ge m p h a s i s w i l l
10、 b e i n th e ch a l le n g e of th e i n d iv id u a l w or k e r . M e n on p r od u c t ionl i n e s ca n b e com e te a m s , colle c t i ve l y r e s p on s i b l e for th e e n d p r od u c t r a th e r th a n for ju s t s o m a n y r e p e t i t iou s op e r a t i on s . U n d e r th i s con
11、ce p t , i t i s th e te a m s r e s p on s i b i l i ty to h e lp d e te r m i n e th e d i s t r i b u t i on of w or k , th e occu p a t i on of m a ch i n e s , a n d th e s p e e d a n d q u a l i ty of w or k . I t i s a s s u m e d th a t th e p e r s on n e l w i l l b e g ive n b r oa d e r
12、 t r a i n i n g s o th a t th e y m i g h t h a ve th e fle x i b i l i ty a n d a l l a r ou n d s k i l l to b e a b le to s te p i n w h e r e h e lp i s n e e d e d .M od e r n m a n u fa c tu r in g p l a n n i n g a l s o in c lu d e s th e u s e of th e com p u te r to h a n d le th e va s t
13、 a m ou n t of d a ta n e e d e d to u t i l i ze r a w i n for m a t i on , s u ch a s s a l e s for e ca s t s a n d cu s tom e r or d e r s , in d e te r m in i n g w h a t i s to b e p u r ch a s e d , m a d e , s tor e d , e tc ( s h ow n i n F i g u r e 5 - 1) .Th e com p u te r , i n c lu d i
14、 n g th e m in i com p u t e r a n d p r og r a m m a b le con t r o l l e r s , w i l l h a ve i n cr e a s e d im p a ct i n th e a r e a s of p r od u c t , tool, a n d p r oce s s d e s ig n for op t im u m p r od u c t i on . Com p u te r - a i d e d d e s i g n ( CAD) a n d com p u te r - a id
15、 e d m a n u fa c tu r e ( C AM ) h a ve th e p ote n t i a l of b e i n g th e l a r g e s t s i n g le d e ve lop m e n t m a n u fa c tu r in g s i n ce th e in d u s t r i a l r e volu t i on . W h e th e r th e fu l l p ote n t i a l w i l l b e r e a l i ze d i s d e p e n d e n t on i t s a c
16、ce p ta n ce b y i n d u s t r y a n d b y colle g e s a n d u n ive r s i t i e s w h e r e fu tu r e m a n u fa c tu r i n g e n g i n e e r s a r e t r a i n e d . Th i s i s n ot to im p l y th a t con s id e r a b le l e a r n in g d oe s n ot ta k e p l a ce ou t s i d e of th e for m a l c l
17、a s s r oom . On th e con t r a r y , b e ca u s e of tod a y s flood of n e w s c i e n t i fi c a n d te ch n i ca l k n ow l e d g e , a n d th e a s ton i s h i n g p a ce of te ch n o log i ca l ch a n g e , th e e n g i n e e r r i s k s ob s o le s ce n ce u n le s s h e m a k e s s om e p l
18、a n s for s e lf- s tu d y . H ow e ve r , e ve n s h or t cou r s e s a n d colloq u i u m s m a y n ot b e s u ffi cie n t . F or m a n y a r e a s of r a p i d te ch n o log i ca l ch a n g e , a w or k cy c l e of fou r or fi ve y e a r s fo l low e d b y a y e a r on ca m p u s m a y b e a n or
19、 m a l p r a c t i ce .ComputerData banksComputer programsSalesforecastCustomerorIdn eprustProducttypesPurchasing controlOrdersManufact- uring controlAssembly worksheets Warehouse sheets Code booksCost price break-downou tp u tF i g u r e 5 - 1Th e com p u te r , w i th i t s d a ta b a n k s a n d
20、p r og r a m s , i s a n e s s e n t i a l p a r t of m a n u fa c tu r i n g p l a n n i n gA u t o m a t i o n“A u tom a t i on ”is a r e l a t i ve l y n e w w or d , coin e d in 19 3 5 b y D. S . H a r d e r , th e n vice p r e s id e n t i n ch a r g e of m a n u fa ctu r i n g for th e F or d
21、M otor C om p a n y . Th e w or d , s h or t for “a u tom a l i za t i on ”i m p l i e s d o i n g s om e th i n g a u tom a t i ca l l y or w i th ou t h u m a n a s s i s ta n ce . Th i s m a y r e fe r to a s i n g leAutomationop e r a t i on or a n e n t i r e con t i n u ou s p r oce s s .Au to
22、m a t i c con t r ol s y s te m s a r e n ot a p r od u ct of th i s g e n e r a t i on , J a m e s W a t t , a s e a r l y a s 178 8 , con ce ive d of a n a u tom a t i c s p e e d con t r o l for h i s s te a m e n g i n e i n th e for m of a fly - b a l l g ove r n or . Th e tw o fly b a l l s ,
23、a c t i n g b y ce n t r i fu g a l for ce , w ou ld e x te n d a s th e r p m of th e e n g i n e i n cr e a s e d . Th i s , i n tu r n , ca u s e d a m otion th a t r e d u ce d th e op e n in g a t th e in ta k e va lve . W i th l e s s s te a m i n ta k e , th e s p e e d r e d u ce d a n d th
24、e b a l l s m ove d c los e r to th e con t r o l s h a ft , th u s r e op e n i n g th e i n ta k e va lve .An oth e r e x a m p le of e a r l y a u tom a t i on th a t i s s t i l l com m on i n m a n y s h op s i s th e fu l l y a u tom a t i c s cr e w m a ch in e . Th e i n ve n tor , Ch r i s
25、top h e r S p e n ce r , h a d w or k e d on m a n u a l l y op e r a te d tu r r e t l a th e s . H e r e a l i ze d th a t b y a t ta ch i n g a ca m s h a ft , s t r i p ca m s , le ve r s , a n d s e g m e n t g e a r s for a c tu a t i n g th e tu r r e t , colla te , a n d cr os s s l id e , i
26、 t cou ld b e m a d e to op e r a t e a u tom a t i ca l ly . Th u s th e a u tom a t i c s cr e w m a ch i n e w a s b or n . S u r p r i s i n g ly e n ou g h , S p e n ce r d id n ot r e a l i ze th e im p or t of h i s i n ve n ti on b u t w a s con te n t to l e t th e m a ch i n e p r od u ce
27、s cr e w s a n d oth e r s im i l a r i te m s r a th e r th a n to d e ve lop th e m a ch i n e i t s e l f.Ab ou t th e s a m e t im e a s S p e n ce r s a u tom a t i c s cr e w m a ch i n e w a s b u i l t i n th e U n i te d S ta te s , th e S w i s s w e r e w or k i n g ou t s im i l a r i d
28、e a s for a n a u tom a t i c s cr e w m a ch i n e . Th e r e s e e m s to b e s om e r e lu c ta n ce to g i ve a n y on e m a n cr e d i t for th e i n ve n t i on of w h a t h a s com e to b e k n ow n a s th e S w i s s a u tom a t i c s cr e w m a ch i n e . H ow e ve r , th e con t r i b u t
29、i on s of a b r i l l i a n t y ou n g e n g in e e r n a m e d B a ch e lor ca n n ot b e i g n or e d . H i s con ce p t of m ovin g th e m a te r i a l a x i a l l y a s i t w a s b e i n g cu t p r ovid e d a m e a n s of g e n e r a t i n g a n i n fi n i te va r i e ty of s h a p e s w i th a
30、m in im u m of toolin g . Th e m a ch i n e , e n t i r e l y ca m - op e r a te d ,4Numerical Controlw a s fu l ly a u tom a t ic . On e m a n cou ld look a fte r fi ve or s i x of th e s e m a ch i n e s , p r im a r i l y to s e e th a t th e y d i d n ot r u n ou t of m a t e r i a l a n d th a
31、t th e p a r t s p r od u ce d w e r e w i th i n tole r a n ce lim i t s .N u m e r i c a l c o n t r o lA r e l a t ive l y s h or t t im e a g o m a ch i n e s w e r e op e r a te d b y cr a fts m e n w h o d e te r m in e d m a n y va r i a b le s s u ch a s s p e e d s , fe e d s , d e p th of
32、cu t , e tc . N ow m u ch of th i s w or k i s b e i n g a s s i g n e d to com p u te r s a n d m a ch i n e s th a t a r e n u m e r i ca l ly con t r olle d . Th e w or d n u m e r i ca l i s d e fin e d a s “t h e e x p r e s s i on of s om e th in g b y n u m b e r s ”. Con t r o l i s d e fin
33、e d a s “t h e e x e r c i s e of d i r e c t i n g , g u id in g , or r e s t r a in i n g p ow e r ove r s om e th i n g ”. B y com b i n i n g th e tw o d e fin i t i on s w e fin d th a t n u m e r i ca l con t r ol con s i s t s of d i r e ct in g , g u i d i n g , or r e s t r a i n i n g p ow
34、 e r ove r s om e th i n g b y th e u s e of n u m b e r s . S in ce n u m b e r s a r e m e r e l y s y m b ols a n d l e t te r s a r e u s e d a s w e l l, n u m e r i ca l con t r o l cou ld w e l l b e ca l l e d s y m b o l i c con t r o l .Nu m e r i ca l con t r o l h a s b e com e com m on
35、p l a ce i n th e w or ld of m a ch i n e tools , op e n i n g u p n e w d oor s for m or e a d va n ce d con ce p t s . Tod a y , e n t i r e p r e p la n n e d a n d p r og r a m m e d d e s i g n a n d p r od u c t i on fu n c t i on s ca n b e p r oce s s e d , s tor e d , a n d fi n a l l y e x
36、e cu te d w i th th e a i d of a com p u te r . Th e s e fu n c t i on s a r e te r m e d CN C ( com p u te r n u m e r ica l con t r o l ) , CAD ( com p u te r - a id e dd e s ig n ) , CAM ( com p u te r - a id e dm a n u fa c tu r in g ) ,a n dCIM( com p u te r - i n te g r a te d m a n u fa c tu
37、r in g ) .Nu m e r i ca l con t r o l ( NC ) i s con s id e r e d to b e m or e th a n a n im p r ove d con t r ol for m a ch i n e tools th a t p r ovid e s h i g h e r p r od u c t iv i ty . I t i s con s i d e r e d b y m a n y l e a d i n g s c ie n t i s t s to b e th e fi r s t s i g n i fi ca
38、 n t s te p in w h a t i s r e fe r r e d to a s th e s e con d i n d u s t r i a l r e volu t ion . Th e fi r s t i n d u s t r i a l r e volu t i on w a s u s h e r e d i n b y J a m e s W a t t s s te a m e n g in e . H u m a n m u s c le p ow e r w a s r e p l a ce d a n d e x te n d e d5Numeric
39、al Controli n to a l l ty p e s of i n d u s t r i a l e q u i p m e n t . Th e s e con d r e volu t i on i s a n e x te n s i on of m a n s m i n d . N C, w i th th e a id of th e com p u te r , t a k e s a s y m b o l i c in p u t a n d r e s t r u c tu r e s i t to a n ou tp u t th a t e x te n d
40、 s m a n s con ce p t s a n d th i n k i n g i n to cr e a t ive , p r od u c t i ve r e s u l ts .Th e b i r th of NC m a y b e t r a ce d to th e l a te 19 4 0 s . At th a t t im e J oh n P a r s on s a n d h i s a s s ocia te s w e r e m a n u fa c tu r i n g h e l i cop te r b l a d e s . Th e y
41、 fou n d th e s p e ci fica t i on s , con tou r s , a n d w e i g h t s of th e a i r fo i l ve r y cr i t i ca l a n d d e m a n d i n g . S t r u g g li n g w i th th e con tou r of th e r otor b l a d e , th e y d e vis e d a n i n cr e m e n t a l ly m ovin g d im e n s i on a l i n s p e c t i
42、 on s y s te m . Th e a u th or e d d im e n s i on a l d a ta w e r e fe d i n to a n e a r l y m od e l com p u te r th a t con ta i n e d th e p u r e m a th e m a t i ca l for m u l a for th e a i r foi l . Th e i n s p e c t i on d a ta w e r e com p a r e d to th e b a s i c for m u l a . Th e
43、 id e a w or k e d s o w e l l th a t M r . P a r s on s con c lu d e d th a t i f a com p u te r cou ld te l l w h a t h a d h a p p e n e d a fte r a p a r t w a s m a d e , w h y n ot u s e th e s a m e d a ta to con t r o l a m a ch i n e tool m a d e th e p a r t . A con ce p t i s fa r fr om r
44、 e a l i t y , of cou r s e . H ow e ve r , i n 19 4 9 th e U . S . Air F or ce , w h i ch r e cog n i ze d th e va lu e of th e te ch n iq u e , a w a r d e d a d e ve lop m e n t con t r a c t to th e M a s s a ch u s e t t s In s t i tu t e of Te ch n olog y a n d b y 19 5 2 th e fi r s t n u m e
45、 r i ca l l y con t r o l l e d m a ch i n e tool w a s op e r a t i on a l .Nu m b e r s , l e t te r s , a n d s y m b o l s g a th e r e d tog e th e r a n d log i ca l l y or g a n i ze d to d i r e c t a m a ch i n e tool for a s p e c i fi c ta s k a r e ca l le d a n NC p r og r a m . Th e co
46、n ce p t i s r e volu t i on a r y in th a t th e con t r o l of a m a ch i n e h a s b e e n m ove d a w a y fr om op e r a tor s k i l l a n d in tu i t i on to a n e n t i r e l y w r i t te n p r og r a m th a t ca n b e i n te r p r e te d b y th e m a ch i n e con t r o l u n i t to p e r for
47、m a l l th e r e q u i r e d m ove m e n t s th a t p r od u ce a fin i s h e d p a r t , n ot on l y h a s NC r e p l a ce d h u m a n s k i l l s a n d i n tu i t i on , b u t i t h a s m a d e i t p os s i b le to g e n e r a te com p le x m a ch in e m otion s6Numerical Controlw i th a d e g r e e of p r e c i s i on th a t i s fa r b e y on d a n y h u m a n ca p a b i
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