L 2*. 3 '

W37

OUTLOOK FOR NUMERICAL CONTROL 

OF MACHINE TOOLS

28 ’65

A Study of a

Key Technological Development

in Metalworking Industries

Bulletin No. 1437

U N ITE D S T A T E S D E P A R TM E N T OF LADOR 

W . W illard W irtz, S ecretary

B U R E A U OF L A B O R S T A T I S T I C S 

Ew an C lague, C o m m iss io n e r

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OTHER BLS PUBLICATIONS ON AUTOMATION AND PRODUCTIVITY

M an p ow er P lanning to A dapt to New T e ch n o lo g y A t an E le c t r ic and G as U t ilit y --A C ase Study 

(R ep ort N o. 293, 1965).

T ech n iq u es u se d to fa cilita te m an p ow er a d ju stm en ts. C o v e r s th ree te ch n o lo g ic a l in n ovation s a ffe ctin g 

m o r e than 1 ,9 0 0 w o r k e r s .

C a se S tu dies o f D is p la c e d W o rk e r s (B u lletin 1408, 1964), 94 pp. , 50 c e n ts .

E x p e r ie n c e s o f w o r k e r s a fte r la y o ff. C o v e r s o v e r 3, 000 w o r k e r s fr o m fiv e plants in d ifferen t 

in d u s tr ie s.

T e c h n o lo g ic a l T re n d s in 36 M a jo r A m e r ic a n I n d u s tr ie s , 1964, 105 pp. Out o f p rin t, a v a ila b le in lib r a r ie s .

R e v ie w o f sig n ifica n t te c h n o lo g ic a l d e v e lo p m e n ts, w ith c h a r ts on e m p loy m en t, p rod u ction ,a n d 

p ro d u c tiv ity . P r e p a r e d fo r the P r e s id e n t's A d v is o r y C om m ittee on L a b o r-M a n a g e m e n t P o lic y .

Im p lic a tio n s o f A u tom a tion and O ther T e c h n o lo g ic a l D e v e lo p m e n ts: A S e le c te d A nn otated B ib lio g ra p h y 

(B u lletin 1 3 1 9 -1 . 1963), 90 pp. , 50 c e n ts . S upplem en t to b u lle tin 1319, 1962, 136 pp. , 65 ce n ts.

D e s c r ib e s o v e r 300 b ook s, a r t ic le s , r e p o r t s , sp e e c h e s , c o n fe r e n c e p r o c e e d in g s , and oth er r e a d ily 

a v a ila b le m a te r ia ls p u b lish ed p r im a r ily betw een 1961 and 1963.

In d u stria l R e tra in in g P r o g r a m s fo r T e c h n o lo g ic a l C hange (B u lletin 1368, 1963), 34 pp. Out o f p rin t, a v a ila b le 

in lib r a r ie s .

A study o f the p e rfo rm a n ce o f o ld e r w o r k e r s b a sed on fo u r c a s e stu d ies o f in d u stria l p lan ts.

Im p a ct o f O ffice A u tom a tion in the In tern al R evenu e S e r v ic e (B u lle tin 1364, 1963), 74 pp. Out o f p rin t, 

a v a ila b le in lib r a r ie s .

A c a s e study h igh ligh tin g m a n p ow er planning and em p loy m en t im p a c ts d u rin g a m a jo r c o n v e r s io n to 

o ffic e au tom ation in the F e d e r a l G ov ern m en t.

Im p a ct o f T e c h n o lo g ic a l C hange and A u tom a tion in the P u lp and P a p e r In d u stry (B u lletin 1347, 1962), 92 pp. , 

50 c e n ts .

G e n e ra l in d u stry su rv e y and th ree c a s e stu d ies h igh ligh tin g im p lic a tio n s o f te ch n o lo g ic a l chan ge fo r 

p ro d u ctiv ity , em p loy m en t, and in d u stria l r e la tio n s .

T e c h n o lo g ic a l C hange and P ro d u c tiv ity in the B itu m in ou s C oa l In d u stry , 19 20-6 0 (B u lletin 1305, 1961),

136 p p . , o5 c e n ts .

T re n d s in te ch n o lo g y and p ro d u ctiv ity and im p lic a tio n s fo r e m p loy m en t, u n em p loy m en t, w a g e s, p r ic e s , 

and p r o fits .

A d ju stm en ts to the In trod u ction o f O ffic e A u tom a tion (B u lletin 1276, I9 6 0 ), 86 pp. , 50 ce n ts.

A study o f som e im p lic a tio n s o f the in s ta lla tio n o f e le c tr o n ic data p r o c e s s in g in 20 o ffic e s in p riv a te 

in d u stry , w ith s p e c ia l r e fe r e n c e to o ld e r w o r k e r s .

S tu dies o f A u tom a tic T e ch n o lo g y (F r e e ).

A s e r ie s o f c a s e stu d ies o f plants in trod u cin g a u tom ation . D e s c r ib e s ch a n g es and im p lic a tio n s fo r 

p ro d u ctiv ity , em p loy m en t, occu p a tio n a l re q u ir e m e n ts, and in d u s tria l r e la tio n s .

A C a se Study o f a C om p an y M an u factu rin g E le c tr o n ic E q u ip m en t.

A C a se Study o f a L a r g e M e ch a n iz e d B a k ery (R e p o r t 109).

A C a se Study o f a M o d e r n iz e d P e tr o le u m R e fin e ry (R e p o r t 120).

A C a se Study o f an A u tom a tic A ir lin e R e s e r v a tio n S y stem (R e p o r t 137).

S a les p u b lica tio n s m a y be p u rch a se d fr o m the S up erin ten d en t o f D ocu m en ts, W ash in gton , D. C. 20402, 

o r fr o m r e g io n a l o ff ic e s o f the B u rea u o f L a b o r S ta tistics at the a d d r e s s e s show n b e lo w . F r e e p u b lica tion s 

a r e a v a ila b le , as lon g as the su pp ly la s t s , fr o m the B u rea u o f L a b o r S ta tis tic s , U .S . D ep artm en t o f L a b o r ,

W ashin gton , D .C . 20212.

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B oston , M a s s . 02110

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219 South D e a rb o rn S treet 

C h ica g o , 111. 60603

M id d le A tla n tic R eg ion 

341 N inth A venu e 

N ew Y o rk , N . Y . 10001

S outhern R eg ion

1371 P e a c h tre e S treet, N E .

Suite 540

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E a st C en tra l R e g io n 

1365 O n ta rio S treet 

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B ox 36017

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OUTLOOK FOR NUM ERICAL CONTROL 

OF MACHINE TOOLS

A Study of a

Key Technological Development

in Metalworking Industries

Bulletin No. 1437

March 1965

UNITED STATES DEPARTMENT OF LABOR

W. Willard Wirtz, Secretary

BUREAU OF LABOR STATISTICS

Ewan Clague, Commissioner

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Washington, D.C., 20402 - Price 40 cents

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Preface

Under the Manpower Development and Training Act of 1962, the

Secretary of Labor is required to establish techniques and methods for

detecting in advance the potential manpower impact of automation, technological progress, and other changes in the structure of production. This

type of early warning system could be of great assistance to management and

union leaders, educators, government officials, economists, and others in

planning policies to cushion the impact of change.

This bulletin deals with the outlook for and implications of a key

technical innovation in the metalworking industries, still in a very early

stage of application. Widespread adoption of numerical control of machine

tools could have significant effect on productivity, occupational requirements,

training programs, employment and industrial relations.

The study was based on information obtained through review of

trade and technical publications, attendance at conferences and seminars,

and discussions with producers and users of numerical control and with

union officials. The Bureau of Labor Statistics is grateful to the many individuals in various companies, unions, trade associations, educational institutions, research establishments,and government agencies who furnished

valuable information and reviewed and commented on the draft of this report.

Special acknowledgment for providing photographs is due to Cincinnati

Milling and Grinding Machines, Inc. , Giddings and Lewis Machine Tool Co. ,

Kearney and Trecker, Pratt and Whitney, and Westinghouse Electric Corp.

The bulletin was prepared by John Macut in the Bureau1 s Division

of Technological Studies under the supervision of Edgar Weinberg, Chief,

and under the general direction of Leon Greenberg, Assistant Commissioner

for Productivity and Technological Developments.

m

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Federal Reserve Bank of St. Louis
Contents

Summary and highlights----------------------------------------------------------------------- 1

Automatic control by coded tape instructions -------------------------------- 1

Extent of use still lim ited--------------------------------------------------------------- 2

Metalworking industries affected---------------------------------------------------- 2

Favorable prospects for rapid diffusion----------------------------------------- 2

Reduced unit labor requirements---------------------------------------------------- 2

Important operating advantages ------------------------------------------------------ 3

Changes in occupational pattern --------------- ------------------------------------ 3

Numerical control generates new training needs -------------------------- 3

Need for changes in training programs------------------------------------------- 5

Significance of numerical control to metalworking industries------ 5

Possible employment changes in some machining occupations---- 5

Employment impact depends on economic growth-------------------------- 6

Labor-management adjustments may be needed---------------------------- 6

Chapter L Introduction --------------------------------------------------------------------- 7

Evolution of machine tools -------------------------------------------------------------- 7

Present trend toward automation---------------------------------------------------- 8

Chapter 2. Numerical control in machine-tool technology------------- 9

Relation to conventional machine tools ----------------------------------------- 9

Development of numerical control--------------------------------------------------- 9

Two types of numerical control------------------------------------------------------ 10

Future directions of numerical control ----------------------------------------- 12

Chapter 3. Status of numerical control applications ----------------------- 15

Number shipped-------------------------------------------------------------------------------- 15

Types of numerical control u s e d ---------------------------------------------------- 16

Applications in metalworking industries --------------------------------------- 17

Chapter 4. Outlook for numerical control --------------------------------------- 21

Supply of equipment ------------------------------------------------------------------------- 21

Potential demand ---------------------------------------------------------------------------- 21

Market for numerical control---------------------------------------------------------- 22

Government programs --------------------------------------------------------------------- 25

Price and demand---------------------------------------------------------------------------- 26

Chapter 5. Impact on labor requirements per unit of output ---------- 29

Reduction in unit labor requirements --------------------------------------------- 29

Operating economies------------------------------------------------------------------------- 31

Saving in capital requirements ------------------------------------------------------ 31

Chapter 6. Changes in occupational requirements -------------------------- 33

Greater importance of planning and programing -------------------------- 33

Part programer ------------------------------------------------------------------------------ 36

Changes in content of machine tool operator jobs ------------------------- 37

Changes in maintenance jobs--------------------------------- 38

Changes in tooling jobs ------------------------------------------------------------------- 40

Changes in drafting and designer jobs ------------------------------------------- 40

Fage

v

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Contents— Continued

C h apter 7. T rain in g fo r n u m e ric a l c o n t r o l--------------------------------- 41

C om pany train in g fo r n u m e ric a l c o n t r o l----------------------------------- 41

Im p lic atio n s fo r v o catio n al education -------------------------------------- 42

A p p ren ticesh ip train in g p ro g ra m -------------------------------------------- 42

A dult edu cation fo r re tra in in g m a c h in ists ------------------------------- 43

P r o fe s s io n a l se m in a r s e s s i o n s ------------------------------------------------ 43

C h apter 8. Im p licatio n s fo r e m p lo y m e n t------------------------------------ 47

L a b o r d isp la c e m e n t and e x p a n s io n ------------------------------------------- 47

Im p licatio n s fo r equipm ent p r o d u c e r s-------------------------------------- 48

E m ploym en t in the m etalw ork in g in d u stry group ---------------------- 48

E m ploym en t ch an ges in sp e c ific m achin ing o c c u p a t io n s------------ 50

C h apter 9. L a b o r-m a n a g e m e n t a d ju s t m e n t s------------------------------- 53

M ethod of determ in in g sk ill le v e l and w age r a t e s ---------------------- 53

M ethods of ad ju stin g to d isp la c e m e n t -------------------------------------- 54

A ppen dix. S e le c te d b ib lio grap h y on outlook fo r n u m e ric a l

con tro l of m ach in e t o o l s ---------------------------------------------------------- 57

T a b le s:

1. D o m e stic sh ip m en ts of n u m e ric a lly co n tro lled m achin e

to o ls, se le c te d y e a r s , 1954-63 -------------------------------------- 15

2. N um ber of n u m e ric a lly co n tro lled m ach in e to o ls shipped

and on o r d e r , by ty pe, 1954-63 ------------------------------------ 17

3. D istrib u tio n of m a n u fa c tu r e r s1 sh ip m en ts of n u m e ric a lly

co n tro lle d m ach in e to o ls, by m a jo r in d u stry g ro u p , by

type of c o n tro l, 1954-63 ------------------------------------------------ 18

4. P e rc e n t of fo u r c a te g o r ie s of m e ta l-c u ttin g m ach in e to o ls

at le a s t 10 y e a r s old, 1963 --------------------------------------------- 22

5. D istrib u tio n of fou r c a te g o r ie s of m e ta l-c u ttin g m ach in e

to o ls at le a s t 10 y e a r s old, by in d u stry , 1963 ----------------- 23

6. C a p ital spending p lan s of m etalw o rk in g m an u factu rin g

c o m p a n ie s, 1964-67 ------------------------------------------------------ 24

7. Spending fo r au tom ated m ach in ery by m etalw o rk in g

in d u str ie s, se le c te d y e a r s --------------------------------------------- 25

8. V alue of sh ip m en ts and a v e ra g e unit v a lu e s of n u m e ric a l

co n tro lled m ach in e to o ls, by ty p e, 1954-63 --------------------- 26

9. R ep o rted la b o r and other c o st sa v in g s of n u m e ric a lly

co n tro lled v e r s u s conventional m ach in in g ---------------------- 30

10. O p eratio n al flow under conventional and n u m e ric a l m ach in e

tool c o n t r o l ------------------------------------------------------------------ 34

11. T h ree c o m p a rativ e c a se stu d ie s of m an -h o u r r e q u ir e ­

m e n ts: conventional and n u m e ric a lly co n tro lled

m ach in in g ------------------------------------------------------------------- 35

P age

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Contents— Continued

T a b le s - - Continued

12. D e sc rip tio n of d u ties and know ledge and a b ility re q u ire d in

P ag e

n u m e ric a l con trol p o sitio n s at one a ir c r a f t p a r ts

p r o d u c e r---------------------------------------------------------------------- 39

13. Content of train in g c o u r se s on n u m e ric a l con trol open at

a Uo S. G overn m en t m etalw o rk in g i n s t a l l a t i o n ----------------- 44

14. A v e ra g e w eekly h o u rs and o v ertim e h o u rs of p rod u ction

w o rk e rs in m etalw ork in g in d u str ie s, 1964 ---------------------- 49

Vll

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OUTLOOK FOR NUMERICAL CONTROL OF MACHINE TOOLS

Su m m ary and H igh ligh ts

N u m e ric a l con trol (N /C ) of m ach in e to o ls is a re la tiv e ly new te c h ­

nique of ad van ced au to m atic m ach in in g which opens p o s s ib ilit ie s fo r a fa s t e r 

ra te of grow th in p ro d u ctiv ity w ithin the im p o rtan t m etalw o rk in g se c to r of 

the econom y. N u m e ric a l con trol is p a r tic u la r ly su ita b le fo r the m an u factu re 

of a v a rie ty of d ifferen t m e ta l p a r ts in sm a ll v o lu m e--th e job shop type of 

prod u ction which c o m p r ise s a la r g e p a rt of the m etalw o rk in g in d u stry . The 

tech n iq u es and equipm ent now u se d g e n e ra lly in th is type of p rod u ction lag 

c o n sid e ra b ly behind the high d e g re e of m ech an izatio n in m a s s prod u ction of 

sta n d a rd iz e d m e ta l p a r t s .

Although u se of n u m e ric a lly co n tro lled m ach in e to o ls is s till 

lim ite d , the p r o sp e c ts fo r ra p id d iffu sio n o v er the next few y e a r s a r e highly 

fa v o ra b le .

The sa m e o p e ratio n s n e c e s s a r y to conventional m ach in in g a r e 

re q u ire d fo r n u m e ric a l co n tro l, but d ifferen t ta s k s and sk ill re q u ire m e n ts 

a r e c r e a te d , e sp e c ia lly fo r the o ccu p ation s of plan n in g, m ach in e o p e ra to r, 

and m ain ten an ce. It c r e a te s a new occu pation of " p a r t ” p r o g r a m e d Since 

the p ro c e d u re s and o p eratio n of n u m e ric a l con tro l a r e new to the m achin ing 

w ork fo r c e , w o rk e rs m u st be tra in e d to u tilize th is tech n ique.

A s long a s the econom y is expanding, the in trod u ction of n u m e ric a l 

con trol m ay not r e su lt in ex ten siv e la b o r d isp la c e m e n t, but la b o r - m a n a g e ­

m ent a d ju stm e n ts to p ro vid e fo r o rd e rly ch an geover w ill be re q u ire d .

A utom atic C on trol by Coded T ape In stru ctio n s

P re v io u s ch an ges in m ach in e-tool techn ology involved la r g e ly 

im p ro v em en ts in p o w er, sp e e d , and sp e c ia liz a tio n . N u m e ric a l con trol 

p e rm its au to m atic o p eratio n of m ach in e to o ls by such m e an s a s a sy ste m of 

e le c tro n ic d e v ic e s (con trol un its) and ch an geable ta p e s. The co n tro l unit 

in te rp re ts coded tape in stru c tio n s (p re p a re d in ad van ce by the p ro g ra m e r) 

and can d ire c t the m ach in e tool a u to m a tic a lly through the p ro g ra m e d sequen ce 

of m ach in in g o p e ratio n s (d rillin g , m illin g , b o rin g, tu rn in g, e tc. ) w hile 

co n tro llin g m ach in in g sp e e d s and fe e d s, d ista n c e and d ire c tio n of m ovem ent 

of the tool o r w o rk p iece, flow of coolan t, and even the se le c tio n of the p ro p e r 

p r e s e t cutting tool fo r each o p eratio n . In o p eratin g m o st conventional 

m ach in e to o ls u se d in the sm a ll lot m an u factu re of m e ta l p a r t s , such m ach in e 

setup and con tro l condition s a r e la r g e ly d eterm in ed and m an u ally a r ra n g e d 

by the o p e ra to r. In ad d ition , ex p en siv e fix tu r e s , ji g s , and te m p la te s to hold 

the w ork in p la c e and to guide the cutting tool a r e n eeded.

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E xten t of U se S till L im ite d

N u m e ric a l con trol is still in an e a r ly sta g e of developm en t and 

c o m m e rc ia l u se but the grow th ra te h as in c r e a se d in recen t y e a r s . A to tal 

of 3 ,3 6 5 un its w ere sh ipped by p ro d u c e rs to d o m e stic u s e r s betw een the 

beginning of 1954 and the end of 1963; but 64 p e rc e n t of th e se w ere sh ipped 

in 1962 and 1963, and 611 (including a sm a ll n um ber fo r export) m o re w ere 

on o rd e r at the end of 1963.

M etalw orkin g In d u strie s A ffected

About 55 p e rc e n t of a ll n u m e ric a lly co n tro lled m ach in e to o ls w ere 

sh ipped to s ix m a jo r in d u strie s en gaged in sm a ll batch m etalw o rk in g p ro d u c ­

tion : a ir c r a f t , m etalw o rk in g m ach in e ry , s p e c ia l in d u stria l m ach in e ry , 

g e n e ra l in d u stria l m ach in e ry , m ach in e shop, and co n stru ctio n equipm en t. 

E v e ry m a jo r m etalw ork in g in d u stry , h ow ev er, h a s at le a s t one n u m e ric a lly 

co n tro lled too l. The m o to r v e h ic le s and p a r ts in d u stry , a r e adopting in ­

c r e a sin g ly th is technique of m ach in in g to re p la c e the c o stly and tim e - 

con sum in g m eth od s of produ cin g the la r g e am ount of to o ls, d ie s , and fix tu re s 

n eeded in o p eratin g th e ir h ighly sp e c ia liz e d p ro d u ctio n m a c h in e s.

F a v o ra b le P r o s p e c ts fo r R apid D iffu sion

N u m e ric a l con trol is lik e ly to be adopted in c r e a sin g ly o v er the next 

few y e a r s . The p ro p o rtio n of m ach in e to o ls, 10 y e a r s old and o v e r, which 

m ay be fu lly d e p re c ia te d and hence e co n o m ica lly re p la c e a b le by n u m e ric a lly 

co n tro lled u n its is high throughout m etalw o rk in g. Som e in d u stry e x p e rts 

fo r e s e e 12, 000 in sta lla tio n s of n u m e ric a l con tro l by 1967. E ven th is o p tim is tic e stim a te , h ow ever, le a v e s N /C m ach in e to o ls in a lim ite d sta g e of 

u se -- a b o u t 1 p e rc e n t of a ll m ach in e to o ls p re se n tly in sta lle d . D iffu sion is 

being sp eed ed by in c r e a se d fa m ilia r ity with the u se of n u m e ric a l con tro l and 

g r e a t e r know ledge of its econ om ic a d v a n ta g e s, in c r e a s e d o u tlay s fo r plan t 

and equipm en t (p a rtic u la r ly autom ated ) plan ned by m etalw o rk in g in d u str ie s, 

ta x p r o v isio n s fa v o ra b le to new in v estm en t, and the F e d e r a l G ov ern m en t’ s 

en co u ragem en t of the u se of n u m e ric a l co n tro l in d efen se w ork. The high 

p r ic e of n u m e ric a l con trol re la tiv e to conventional equipm en t is an o b sta c le 

to it s ra p id adoption even though c a p ita l re q u ire m e n ts p e r unit of output a r e 

p ro b a b ly sig n ific a n tly lo w er fo r n u m e ric a l co n tro l. A few sim p lifie d , l e s s 

ex p en siv e m o d e ls of s e v e r a l ty p e s of N /C m ach in e s h ave b ecom e a v a ila b le 

re c e n tly , and a s a la r g e r v a rie ty of m o d e ls a r e m a rk e te d th is m ay in c r e a s e .

R edu ced Unit L a b o r R eq u irem en ts

N u m e ric a l con tro l m a k e s p o ssib le su b sta n tia l red u ction in unit 

la b o r re q u ire m e n ts re la tiv e to conventional m ach in e to o ls. The am ount 

depen ds on the co m p lex ity of the d e sig n of the p a r t, n um ber of p a r t s p r o ­

d u ced , n um ber and type of o p e ra tio n s, type of m ach in e tool (s) fo rm e r ly 

u se d , e tc . Som e e x a m p le s d isc lo se d unit la b o r sa v in g s of 25 to 80 p e rce n t 

o v e r conventional m eth o d s. Such sa v in g s r e su lt fro m m any fa c to r s- - o n e

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n u m e ric a lly co n tro lled tool can re p la c e s e v e r a l conventional to o ls and th eir 

o p e r a to r s, toolin g and setup tim e is red u ced b e c a u se tap e c o n tro ls v irtu a lly 

re p la c e the u se of jig s and fix tu r e s , m ach in in g tim e is sh orten ed sin ce the 

o p e rato r no lo n g e r h as to in te rru p t the w ork cy cle to r e a d ju st the m ach in e 

or to rech eck the b lu ep rin t in fo rm atio n , and tim e to r e p a ir r e je c t s and 

in sp e ct p a r ts is g re a tly red u ced b e c a u se of the g r e a te r c o n siste n c y of a c c u ­

ra c y in rep ro d u ctio n of p a r t s . Although m ain ten an ce, plan n in g, and p r o ­

gram in g (which is not in c u rre d in conventional m ach in ing) re su lt in in c r e a se d 

m a n -h o u rs, they a r e u su a lly m o re than o ffse t by la b o r sa v in g s in the oth er 

o p e ra tio n s.

Im portan t O peratin g A d v an tages

C o st sa v in g s on c e rta in o p e ra tio n s, though u su a lly d ifficu lt to 

d e te rm in e , a r e freq u en tly cited by u s e r s and p ro d u c e rs to ju stify n u m e ric a l 

co n tro l. Shortening of le a d tim e in p rod u ction is p a r tic u la r ly ad v a n tag e o u s, 

fo r e x a m p le , in a e r o sp a c e w ork, b e c a u se it a ffo rd s o p p o rtu n ities to in c o r ­

p o ra te la s t m inute d e sig n ch an ges in a fa s t changing fie ld . B e c a u se of the 

g r e a te r a c c u r a c y and fle x ib ility of n u m e ric a l co n tro l, p a r ts fo rm e r ly u n eco ­

nom ic o r tech n ic ally im p r a c tic a l to prod u ce a r e often fe a s ib le . F e w e r to o ls 

m ean l e s s flo o r sp a c e n eed ed, and sa v in g s in sto r a g e sp a c e can be c o n s id e r ­

ab le sin ce sig n ific a n tly few er jig s and fix tu re s a r e n eeded.

C han ges in O ccu pation al P a tte rn

Although o ccu p ation s n e c e s s a r y under conventional m a c h in in g -- 

p a rt d e s ig n e r s , m ethod p la n n e rs, tooling m en , and m ach in e-tool o p e r a t o r s - - 

a r e s till re q u ire d under n u m e ric a l co n tro l, th e ir fu n ctio n s, re la tiv e le v e l of 

sk ill re q u ir e m e n ts, and d ecisio n m ak in g r e sp o n sib ilitie s ch an ge. M ain tenance b e c o m e s m o re im p o rtan t in te r m s of sk ill re q u ire m e n ts and r e s p o n s ib ility . N u m e ric a l con tro l r e q u ir e s ad d ition al know ledge of se rv o m e c h a n ism s, 

e le c tr o n ic s, and n u m e ric a l co n tro l s y s te m s - - a n d r e sp o n sib ility fo r m uch 

m o re highly p ric e d equipm en t. M uch of the w ork in developin g con tro l d ata 

and in stru c tio n s by m ach in e -to o l o p e r a to r s and toolin g m en under conventional 

tech n iq u es is t r a n s fe r r e d to the planning sta g e and to p ro g ra m in g . The 

o p e ra to r of a conventional m ach in e m u st se t up the m ach in e, including in d e x ­

ing of tab le o r w o rk p iece; se le c tin g the cutting sp e e d and feed ; and ad ju stin g 

the m ach in e se ttin g s to ach iev e p a r t sp e c ific a tio n s. U nder n u m e ric a l co n tro l, 

th ese d u ties a r e a u to m a tic a lly c a r r ie d out by coded tape in stru c tio n s. The 

w ork of an o p e ra to r of a n u m e ric a lly co n tro lled m ach in e tool ten d s to b ecom e 

m on itorin g o r w atching but with added r e sp o n sib ility fo r m uch m o re c o stly 

equipm en t.

N u m e ric a l C on trol G e n e ra te s New T rain in g N eeds

The t a s k s and s k ills a s s o c ia t e d with n u m e ric a l co n tro l re q u ire 

developm ent of new train in g e ffo r ts , p a r tic u la r ly fo r jo b s in m ach in e o p e r a ­

tion , p ro g ra m in g , and m ain ten an ce. It is e stim a te d that m o re than 50, 000 

p e rso n s w ill have had to be tra in e d betw een the end of 1963 and 1967.

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Some Major Steps In Numerical Control Machining

Operator Starts Automatic Operation of a 

Numerically Controlled Drilling and Milling 

Machine

Combining Control Tape and Machine 

/

Design and Drawing of Part

Programing and Preparation of 

Control Tape

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C onventional m ach in ing w o rk e rs re q u ire sp e c ific re tra in in g , but 

a r e g e n e ra lly re a d ily tr a n sfe r a b le to re la te d jo b s under n u m e ric a l co n tro l. 

T rain in g p r o g r a m s a lr e a d y underw ay u su a lly p ro vid e fo rm a l c la s s r o o m 

in stru ctio n at com pany exp en se and o n -th e-jo b train in g fo r p ro g ra m in g and 

m ain ten an ce; o n -th e-jo b train in g alone is g e n e ra lly c o n sid e re d su fficien t fo r 

o p e r a to r s. The length of c la s s r o o m train in g fo r p r o g r a m e r s with a sk ille d 

know ledge of m ach in in g, and fo r m ain ten an ce m en with conventional m a in te ­

nance s k ills and som e know ledge of e le c tro n ic s is u su a lly l e s s than 5 w eek s. 

The o n -th e-jo b train in g fo r th ese two jo b s m ay v a ry fro m 3 w eeks to 6 m on th s. 

A m ach in e-to o l o p e ra to r u su a lly le a r n s to o p e rate a n u m e ric a lly co n tro lled 

tool in a few w eek s.

N eed fo r C han ges in T rain in g P r o g r a m s

While p ro d u c e rs and u s e r s of equipm ent a r e c u rre n tly the p rin c ip a l 

so u r c e s of train in g , in stru c tio n in n u m e ric a l con tro l could be in c o rp o ra te d 

into the c u rric u lu m s of v o catio n al sc h o o ls, ap p re n tic e sh ip p r o g r a m s , te c h ­

n ical in stitu te s, and oth er in stitu tio n s fro m which m ach in in g w o rk e rs le a r n 

th e ir s k ills . E x a m p le s of train in g p r o g r a m s a lr e a d y p ro v id ed by a g o v e rn ­

m ent in sta lla tio n , a State b o a rd of ed u cation , and a p r o fe ssio n a l so c ie ty 

point up the v a rie ty of p o ssib le a p p ro a c h e s.

S ign ifican ce of N u m e ric a l C gn trol to M etalw orkin g In d u strie s

Since th re e -fo u rth s of a ll m etalw ork in g p ro d u ctio n is e stim a te d by 

in d u stry e x p e rts to c o n sist of lo ts n um bering l e s s than 50 p ie c e s , the e m p lo y ­

m ent and oth er econ om ic im p a c ts of n u m e ric a l con tro l could be quite s ig n ifican t. M etalw orkin g in d u strie s - -o rd n an ce, fa b ric a te d m e ta l p ro d u c ts, 

m ac h in e ry , e le c t r ic a l m ach in e ry , tra n sp o rta tio n equipm en t, in stru m e n ts 

and re la te d prod u ct p ro d u c e rs - -em p loy ed 6. 6 m illio n p e r so n s in 1964, 

accoun tin g fo r c lo se to tw o -fifth s of to tal m an u factu rin g em ploym ent in the 

United S ta te s. The w o rk e rs m o st d ire c tly a ffe c te d by the in trodu ction of 

n u m e ric a l con tro l w ill be 1. 1 m illio n m ach in in g w o rk e rs (in a ll s e c to r s of 

m an u factu rin g and n on m anufacturin g) who, in e a r ly 1963, w ere em ployed a s 

a ll-ro u n d m a c h in ists, m ach in e-tool o p e r a to r s , tool and die m a k e r s , in s tr u ­

m ent m a k e r s , and setup and layout m en.

P o s s ib le E m ploym en t C h an ges in Som e M achining O ccu pation s

Grow th in em ploym ent in each m ach in in g o ccu p ation could be slow ed 

by w id e sp re a d u se of n u m e ric a l co n tro l. The extent of the im p act would 

depend on how fa s t in d u stry ad op ts th is new techn ology; and so m e occu p ation s 

a r e lik e ly to be a ffe c te d m o re than o th e rs. E m ploym en t of m ach in e-to o l 

o p e r a to r s is p a r tic u la r ly se n sitiv e to change and lik e ly to be c u rta ile d . 

M ach in ists and in stru m en t m a k e r s- - m a n y of whom w ork in r e p a ir sh ops and 

r e s e a r c h and developm en t la b o r a to r ie s- - w h e r e n u m e ric a l con trol is not 

lik e ly to be u se d e x te n siv e ly --m a y not e x p e rie n c e any se r io u s cu rtailm en t 

in em ploym en t. H ighly sk ille d c ra ftsm e n , such a s to o lm a k e rs and setup 

m en , a r e lik e ly to be a ffe c te d a d v e r se ly sin ce few er ji g s , fix tu r e s , and

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m ach in e se tu p s w ill be re q u ire d . The net e ffe c t on the em ploym ent of the 

v a rio u s occu p ation s w ill depend on a n um ber of fa c t o r s including the fu tu re 

le v e ls of m etalw o rk in g output, the changing unit la b o r re q u ire m e n ts m ade 

p o ssib le by n u m e ric a l co n tro l, and the extent to which d isem p lo y ed w o rk e rs 

can be u tiliz e d in other occu p ation s in the in d u stry . F o r e x a m p le , d eclin e 

in the le v e l of em ploym ent of sk ille d m ach in e-to o l o p e r a to r s and to o lm a k e rs 

could be p a r tia lly o ffse t by the dem and fo r p r o g r a m e r s .

E m p loym en t Im p act D epends on E con om ic Growth

R edu ced la b o r re q u ire m e n ts p e r unit of output m ade p o ssib le by 

n u m e ric a l con trol could r e su lt in d e c r e a se d em ploym en t if the output of 

m etalw o rk in g p lan ts and in d u strie s is d eclin in g, co n stan t, o r in c r e a sin g 

r e la tiv e ly slow ly . In p lan ts and in d u strie s w here output is expanding, 

n u m e ric a l con trol could slow the grow th of em ploym en t. The im p act of 

n u m e ric a l con trol m ay fa ll m o re h eav ily on m a rg in a l p lan ts which do not 

in trod u ce n u m e ric a lly co n tro lled m ach in e to o ls and m ay be unable to c o m ­

pete with the m o re au to m ated m etalw o rk in g p la n ts. E m ploym en t am ong 

p ro d u c e rs of e le c tro n ic co n tro l sy ste m s m ay expand b e c a u se of s a le s in ­

c r e a s e s induced by the e m e rg e n c e of n u m e ric a l co n tro l. B e c a u se of the 

p ro b ab le d e c re a sin g dem and fo r conventional m ach in e to o ls, the net r e su lt 

of the e m e rg e n c e of n u m e ric a l con tro l on fu tu re em ploym ent in the m ach in e 

tool in d u stry is d iffic u lt to d e te rm in e .

L a b o r-M a n a g e m e n t A d ju stm en ts M ay be N eeded

C h an ges in m an u factu rin g p r a c tic e s stem m in g fro m w idening in tro ­

duction of n u m e ric a lly co n tro lled m ach in e to o ls m ay p o se a v a rie ty of 

q u e stio n s fo r co lle c tiv e b a rg a in in g , notably d eterm in atio n of w age le v e ls and 

w age c r it e r ia fo r new jo b s , n e c e s s a r y re v isio n s in in cen tive p la n s, j u r i s ­

d ictio n al p r o b le m s, and m e an s and sta n d a rd s of se le c tio n of p e rso n n e l fo r 

new jo b s . A s the d iffu sio n of n u m e ric a l co n tro l a ffe c ts w id er a r e a s of 

em ploy m en t, unions and m an agem en t m ay find it n e c e s s a r y to give g r e a te r 

atten tion to m e a s u r e s fo r ad van ce n otice and p re p a ra tio n ; fo r avoidin g 

la y o ffs; fo r e a sin g the bu rden of d isp la c e m e n t; and fo r fa c ilita tin g new 

em ploym en t.

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Chapter 1. Introduction

M etalw orkin g in d u strie s em ployed 6 .6 m illio n p e rso n s in 1964 o r 

about 38 p e rc e n t of to tal em ploym ent in m an u factu rin g in the U nited S ta te s. 

O ver 70, 000 p lan ts in th e se in d u strie s p ro d u ced the co n su m e r and p r o ­

d u cer d u rab le goods that c h a r a c te r iz e a highly in d u stria liz e d econom y.

The b a s is of m etalw o rk in g techn ology is o v er 2. 1 m illio n m ach in e 

to o ls. B e c a u se they a r e b a s ic in the rep ro d u ction of th e m se lv e s and the 

produ ction of a ll oth er m a c h in e ry --fro m te x tile lo o m s to tu rb in e s--m a c h in e 

to o ls a r e d e sc rib e d a s " m a s te r to o ls " of the econom y.

In th is study, the te rm "m etalw o rk in g in d u s tr ie s " is u se d to 

c a te g o riz e th o se in d u strie s w here m etalcu ttin g o p e ratio n s a r e b a s ic to the 

p rodu ction techn ology of the p r im a r y end p ro d u c ts. E s s e n tia lly , the te rm 

in clu d es the follow ing six m a jo r Stan d ard In d u strial C la ssific a tio n in d u st r ie s : O rdnance and a c c e s s o r ie s (SIC 19); fa b ric a te d m e ta l p ro d u cts

(SIC 34); m ach in e ry , excep t e le c t r ic a l (SIC 35); e le c t r ic a l m ach in ery 

(SIC 36); tra n sp o rta tio n equipm ent (SIC 37); and in stru m e n ts and re la te d 

p ro d u cts (SIC 38). A few oth er in d u str ie s, such a s p r im a r y m e ta ls 

(SIC 33), w here m etalcu ttin g o p eratio n s a r e p r e se n t but a r e not p r im a r y 

to o v e r a ll ac tiv ity a r e included in so m e of the d ata and a n a ly se s.

Evolution of M achine T o o ls

The evolution of m ach in e to o ls b egan in the f i r s t d ay s of the In dust r ia l R evolution. The "A m e ric a n S y ste m of In terch an geab le P a r t s M an u factu r e "- - th e p rin c ip le of a ll m a s s p ro d u c tio n --w a s u sh e re d in by such d ev elo p ­

m en ts a s E li W hitney’s ji g s , fix tu r e s, and m illin g m ach in e by which 

o p eratin g and co n tro l functions w ere tr a n s fe r r e d fro m the sk ille d handicra ftm e n to the m ach in e tool and sig n ific a n t im p ro v em en ts in p r e c isio n of 

o p eration w ere ach eiv ed . The "A m e ric a n S y ste m , " soon adopted by in d u stry 

u n iv e rsa lly , m a k e s it p o s sib le to p ro d u ce a sp e c ific p a r t of a m ach in e, in 

la r g e n u m b e rs, each p a r t so p r e c is e ly lik e the oth er that any one p a r t can 

be fr e e ly u se d in a sse m b ly of the fin a l p ro d u ct. F ir s t u se d in m akin g m u sk e ts 

and r e v o lv e r s , the m ethod w as extended in the f i r s t h alf of the 19th C entury 

to the m akin g of c lo c k s, fa rm m ach in ery , sew ing m a c h in e s, and oth er d u rab le 

go o d s.

The la tte r h alf of the 19th C entury saw the in trodu ction of a wide 

ran ge of s p e c ia l to o ls. A v a rie ty of to o ls w ere d esig n e d to p e rfo rm one o r 

m o re of the fiv e b a s ic a r t s of m e ta lc u ttin g -- d rillin g , tu rn in g, m illin g , g rin d ­

ing, and plan in g. The in trodu ction of h y d rau lic, pn eu m atic and e le c tr ic co n ­

tr o ls led to g r e a t e r d e g re e of au to m atic o p eratio n . A key ad van ce w as the 

u se of in d ivid u al e le c tr ic m o to rs in p la c e of the b e lt, sh aft, and ste a m en g in es. 

S p e e d s, fe e d s, h o rse p o w e r, and a u x ilia ry equipm ent such a s c a rb id e tipped 

cutting to o ls w ere con tin ually im p ro v ed .

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L a r g e ly b e c a u se of such cu m u lative d ev elo p m en ts, m ach in e tool 

p ro d u ctiv ity h as in c r e a se d ste a d ily . F o r ex am p le, stu d ie s conducted by 

A m e ric a n M ach in ist found m ach in e to o ls of 1958 d e sig n to be, on the 

a v e r a g e , 54 p e rce n t m o re p ro d u ctiv e (output p e r m ach in e hour) than th o se 

d e sig n ed 10 y e a r s e a r lie r . And 1950 m o d e ls w ere found to show a 40- 

p e rc e n t im p ro v em en t o v er th o se p ro d u ced in 1940.

P r e se n t T ren d T ow ard A utom ation

The w ord "au to m atio n ” w as coined in 1946 to d e sc r ib e highly 

au to m atic p rod u ction tech n iq u es f i r s t in trod u ced in the m a s s prod u ction of 

au tom ob ile p a r t s . T h is developm en t c o n sists e sse n tia lly of the in teg ratio n 

of m ach in e to o ls with one an oth er by co n v ey o rs to en able the au to m atic 

p r o c e s s in g and handling of a w ork p iece in, betw een, and out of the m a ­

ch in es. Such t r a n s fe r lin e s, which a r e u se d to p e rfo rm s c o r e s of d iffe re n t 

m ach in in g o p e ratio n s on a p a r t with a m in im u m of hum an a s s is t a n c e , have 

been in trod u ced into m any m etalw ork in g p lan ts p rod u cin g on a m a s s p r o ­

duction b a s is .

Im p ro v em en ts in m ach in e -to o l techn ology c le a r ly have fa r - r e a c h in g 

im p lic a tio n s, not only b e c a u se of the la r g e n um b er of w o rk e rs w hose e m ­

ploym en t m ay be d ire c tly a ffe c te d , but a lso b e c a u se of the stim u lu s to 

m ech an izatio n that could com e even tu ally fro m c o st sa v in g s in p rod u cin g 

in d u stria l m a ch in e ry . C h eap er m ach in ery could u ltim ate ly c r e a te o p p o rtu n ities fo r a f a s t e r p a c e of tech n o lo g ical change and fo r g r e a t e r p ro d u c ­

tiv ity in m an y s e c t o r s of the econom y.

N u m e ric a l co n tro l r e p r e se n ts the la te st m a jo r d evelopm en t in 

m ak in g m ach in in g m o re au to m a tic. U sed p r im a r ily fo r au to m a tic a lly 

prod u cin g p a r t s in sm a ll q u a n titie s, th is innovation d raw s on ad v an ces 

in e le c tro n ic s that have d eveloped out of p o stw a r r e s e a r c h and d e v e lo p ­

m en t. The n atu re of this innovation, the extent of p r e se n t and p r o sp e c ts 

fo r fu tu re u sa g e , and so m e of its p ro b a b le im p lic a tio n s fo r p ro d u ctiv ity , 

o ccu p atio n s, train in g , em ploym ent and in d u stria l re la tio n s a r e co v ere d in 

su b seq u en t c h a p te rs of th is study.

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Chapter 2. Numerical Control in Machine-Tool Technology

N u m e ric a l con trol of m ach in e tools is a technique of au to m atic o p e r ­

ation by m ean s of n u m e ric a l in stru ctio n s e x p r e sse d in code. T h ese in s t r u c ­

tions o r p ro g ra m a r e p re p a r e d in ad van ce. R eco rd ed on punched c a r d s , m a g ­

n etic o r p a p e r ta p e s, th e se coded in stru ctio n s can con trol the seq u en ce of 

m ach in in g o p e ra tio n s; m ach in e p o sitio n s; sp e e d , d ista n c e and d irectio n of 

m ovem en t of the tool or w ork p iece; flow of coolan t; and even the se le c tio n of 

the p ro p e r p r e s e t cutting tool fo r each o p eration . The tap es a r e p lace d on 

a co n tro l u n it--a sy ste m of e le ctro n ic in te rp re tin g d e v ic e s. When the contol unit is ac tiv ita te d , it can d riv e the m ach in e tool through the p ro g ra m e d 

o p e ratio n s and m ovem en ts without any hum an in terven tion . The m ach in e 

o p e r a to r 1 s ro le is lim ited la r g e ly to sta rtin g , stoppin g, loading and unloading, 

and o b se rv in g the tool. The o p e ra to r can change in stru c tio n s e a s ily a fte r each 

job by re p la c in g the ro ll of tape on the con trol unit with an oth er, containing a 

d iffe re n t p ro g ra m .

R elatio n to C onventional M achine T ools

N u m e ric a l con tro l can be b e st u n d erstood by c o m p a riso n with the two 

conventional ty pes of con tro l g e n e ra lly u sed in the o p eratio n of m ach in e to o ls.

In g e n e ra l p u rp o se m ach in e to o ls--th e m o st com m on ty p e --in stru c tio n s about 

d ire ctio n , sp eed , and d ista n c e the tool m u st tr a v e l in cutting a p a r tic u la r p a rt 

a r e e sta b lish e d m an u ally by an o p e ra to r who r e a r r a n g e s v a rio u s elem en ts 

su ch as c a m s, b a r s , and sequ en cin g and cy cle tim e r s ac co rd in g to the n eed s of 

a p a r tic u la r job . The m ach in e o p e ra to r co n su lts b lu ep rin ts and oth er d ata to 

get h is in stru c tio n s. In the secon d ty p e--th e sp e c ia liz e d m ach in e to o l- - in str u c - 

tions about seq u en cin g, p o sitio n in g, and tool tr a v e l a r e built into the m ach in e 

through m e c h a n ic a l- e le c tr ic a l d e v ic e s but th e se a r e r e s tr ic te d to a fixed se t 

of o p e ratio n s fo r m a s s prod u ction of p a r ts of one sp e c ific d esig n . T his type 

of co n tro l is found in types of sp e c ia liz e d au to m atic m ach in e too ls u sed fo r 

m ak in g long runs of the sa m e item . T his secon d type of con trol a ls o r e s u lts 

in a high d e g re e of au to m atic op eration .

Both conventional sy ste m s re q u ire a c o n sid e ra b le tim e (co m p ared to 

n u m e ric a l co n tro l, a s w ill be shown la te r) fo r settin g up the co n tro ls and 

m ak in g exp en siv e tooling su ch a s te m p la te s, jig s * and fix tu re s to guide the 

cutting tool in its o p eratio n . In addition , o p eratio n of conventional m ach in e 

too ls does not ach iev e the high d e g re e of coordin ation and p r e c isio n in h eren t 

in n u m e ric a l co n tro l.

D evelopm en t of N u m e ric a l C on trol

R e se a r c h and developm en t on n u m e ric a l co n tro l--w h ich got u n d e rw ay a fte r 1 9 4 7 --w as a c c e le r a te d by the need of the a ir c r a f t in d u stry fo r new 

m ach in in g tech n iq u es that could p ro d u ce the m any in tric a te ly d esig n ed p a r ts 

of h ig h -sp eed p lan e s ch e ap e r, fa s t e r , and m o re a c c u ra te ly than w as p o ssib le 

with conventional tech n iq u es. A d van ces in com m un ication en gin eerin g, s e r v o ­

m e c h a n ism s and e le c tr o n ic s, p e rfe c te d during W orld W ar II fo r d ire c tin g

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a n tia ir c r a ft fir e , p ro vid ed the b a s is fo r m ak in g n u m e ric a l con trol te ch n ic ally 

p r a c tic a b le .

E a r ly d ev elop m en tal w ork on this innovation w as c a r r ie d fo rw ard 

through jo in t r e s e a r c h e ffo rts of u n iv e r sitie s, the A ir F o rc e ,a n d a ir c r a ft in ­

d u stry . An in itia l study w as conducted in 1948 by a sm a ll a irp la n e p a r ts m a n u ­

fa c tu r e r under a co n tra ct for the U .S . A ir F o r c e . L a te r the M a ssa c h u se tts 

In stitu te of T ech n ology un dertook an exten siv e A ir F o r c e sp o n so re d p r o je c t 

and by the fa ll of 1952, M IT en g in eers and s c ie n tists had s u c c e s s fu lly developed 

the f ir s t n u m e ric a lly co n tro lled m illin g m ach in e, e sta b lish in g the concept of 

n u m e ric a l con tro l p r a c tic a b le fo r in d u stria l u se . R efin em en t of p rin c ip le s and 

tech n iques w as continued at M IT and begun by n u m erou s m ach in e tool b u ild e rs 

and p ro d u c e rs of e le ctro n ic co n tro l and com pu ter equipm ent. In 1955, the 

f ir s t few c o m m e rc ia l m o d els of n u m e ric a lly co n tro lled m ach in e too ls w ere 

d isp la y e d at the N ation al M achine T ool Show and p la c e d into fa c to r ie s fo r o p e r a ­

tio n al u se . B y 1957, n u m e ric a lly co n tro lled m ach in e too ls w ere in sta lle d and 

u sed in prod u ction in v a rio u s A ir F o r c e co n tra c to r p lan ts lo cated a c r o s s the 

country, p ro vid in g an im p o rtan t im p etu s to in d u stria l ap p licatio n .

Sin ce th eir c o m m e rc ia l in troduction , r e s e a r c h and developm en t have 

advan ced n u m e ric a l co n tro l sig n ific a n tly . R e lia b ility of co n tro l com ponents 

h as been in c r e a se d , s p e c ia l sy ste m s fo r a v a rie ty of sp e c ific m ach in e a p p licatio n s have been d e v ise d , and a wide ran ge of com petin g sy ste m s featu rin g 

v ary in g com b in ation s of e le c tro n ic , e le c t r ic a l, h y d rau lic, o p tic a l, p n eu m atic, 

and m e c h a n ic a l co n tro l d e v ic e s have been m ad e a v a ila b le to ch oose fro m . At 

the p r e se n t tim e, m o re than 40 d ifferen t n u m e ric a l cp n tro l sy ste m s a r e 

a v a ila b le .

Two T y pes of N u m e ric a l C on trol

N u m e ric a l co n tro l sy ste m s a r e c la s s ifie d un der two b a s ic fun ction al 

types - -p o sitio n in g and continuous path. P o sitio n in g sy ste m s a r e u sed to contol m ach in e too ls such a s the d r ill and jig b o r e r which p e rfo rm o p e ratio n s only 

at sp e c ifie d poin ts on a w ork p iece. In d rillin g , fo r ex am p le, the d r ill sp in d le 

is p o sitio n ed at a sin g le sp e c ific point; the p ro p e r d r ill s iz e , sp eed and feed 

se le c te d ; the d r ill advan ced to cut a hole to the p ro p e r depth; w ithdraw n when 

co m p leted ; and rep o sitio n ed to cut at the n ext point of w ork. C om pilation of 

the re q u ire d in stru c tio n s fo r o p eratio n of a p o sitio n in g sy s te m - - p r o g r a m in g - - 

can a lm o st alw ay s be e a s ily p e rfo rm e d by a p r o g r a m e r with only the aid of a 

m an u al d e sk c a lc u la to r.

The continuous path sy ste m is u se d to con tro l such m ach in e too ls a s 

the lath e and m illin g m ach in e. Such too ls rem o v e m e ta l con tin uously o v er 

the s u r fa c e of a w ork p iece a s in m illin g a p r o p e lle r b lad e. The p ro b lem is to 

co n tro l con tin uously a cutting tool which re q u ir e s freq u en t ch an ges in m o v e ­

m ent along two o r m o re m ach in e a x e s sim u lta n e o u sly and is in con stan t con ­

ta c t with the w o rk p iece.

The continuous path sy ste m is m o re co m p lex and r e q u ir e s a fa r 

g r e a te r input of d e taile d in stru c tio n a l in fo rm atio n than a p o sitio n in g sy ste m . 

A lthough d ire c t p ro g ra m in g with a d e sk c a lc u la to r is a lso p o ssib le fo r

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While operator monitors, a tape automatically

controls a:

DRILLING MACHINE

ENGINE LATHE

MILLING MACHINE

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continuous path s y s t e m s , it would be too tim e con sum in g fo r p r a c tic a l u se of 

the sy ste m . T h e re fo re , the u se of an e le c tro n ic com p u ter h as b ecom e p r a c ­

tic a lly in d isp e n sib le a s a com puting tool fo r the p r o g r a m e r p re p a rin g in s t r u c ­

tion s fo r m ach in e to o ls co n tro lled by a continuous path sy ste m .

F u tu re D ire ctio n s of N u m e ric a l C on trol

The sig n ific a n c e of n u m e ric a l co n tro l lie s in the p o ssib ility of its 

b ecom in g a m a jo r m ean s of m ak in g m o re au to m atic the prod u ction of ite m s 

that a r e m an u factu red in sm a ll b atch es ra th e r than on a m a ss-p ro d u c tio n b a s is . 

Sin ce in d u stry e x p e rts e stim a te that about th re e -fo u rth s of a ll m etalw o rk in g 

prod u ction c o n sists of ite m s m an u factu red in q u an tities of le s s than 50 p ie c e s , 

the econ om ic im p act of n u m e ric a lly co n tro lled m ach in in g could be quite s ig n ifican t. Such jobbin g prod u ction is com m on to a ll s iz e s of fir m s - - fr o m sm a ll 

m ach in e sh ops em ploying only a few p e r so n s to the la r g e p lan ts em ploying 

thousan ds of w o r k e rs. M o re o v e r, even th ose fir m s which p ro d u ce p r im a r ily 

on a m a ss-p ro d u c tio n b a s is a lso have n u m erou s d ep artm e n ts engaged in 

job bin g p rod u ction .

C u rren t r e s e a r c h and developm en t a r e d ire c te d to ad van cin g n u m e ric a l 

con tro l to the m o st au to m atic, u n iv e rsa l, and fle x ib le type p o s sib le . The fu ­

tu re m ay se e , fo r ex am p le, m o re equipm ent fe atu rin g nad ap tiv e c o n tro l” - - a 

con tro l refin em en t that com b in es au to m atic m ach in in g with con stan t m on ito rin g 

of the r e s u lt s . T h is concept p e rm its a con tin uously au to m atic ad ju stm en t of 

the m ach in e and p ro g ra m e d fe e d s, sp e e d s o r oth er in stru c tio n s to co m p en sate 

fo r such u n co n tro llab le fa c to r s a s v ib ra tio n s, cu ttin g-to o l w e ar, and te m p e r a ­

tu re ch an ges.

A nother in c r e a sin g ly im p o rtan t developm en t is nthe m ach in in g ce n te r, ,! 

a ls o c a lle d m u ltio p eratio n m ach in e, cap ab le of p e rfo rm in g a num ber of o p e r a ­

tion s in m ach in in g a whole p a r t under n u m e ric a l co n tro l. A n um ber of m a ­

chining c e n te rs a r e a lr e a d y on the m a rk e t and in o p eratio n . Such m ach in es 

a r e exp ected to b eco m e a v a ila b le in v a rio u s s iz e s and c a p a b ilitie s. Som e 

m ach in in g c e n te rs can be com plete m ach in e sh op s in th e m se lv e s.

F u rth e r im p o rtan t ad v a n c e s, through the u se of the co m p u ter, a r e 

a lso being m ad e tow ard sim p le r , f a s t e r , and m o re au to m atic p re p a ra tio n of 

the m ach in e in stru c tio n s and con trol tap e s that com m an d the m ach in e. C o m ­

p u ter a s s is t e d p ro g ra m in g c o n sists e sse n tia lly of a sp e c ia lly d e v ise d sy m b o lic 

lan gu age cap ab le of tra n sm ittin g a b r ie f, sim p le d e sc rip tio n o f the m ach in in g 

o p e ratio n s and sh ap e of the w ork p iece to a co m p u ter. In turn, the com pu ter 

c a lc u la te s and t r a n s la te s th e se b r ie f d ire c tio n s into the d e taile d m ach in e in ­

stru c tio n s and coded lan gu age of the co n tro l tap e. C o m p u terized p ro g ra m in g 

h as b ecom e e s s e n tia l in the a p p licatio n s of the continuous path type of n u m e ric a l con tro l w here m an u al p ro g ra m in g p ro v e s too slow , tim e consum ing^and 

u n econ om ic. Its u se , h ow ever, h as been extended to the le s s co m p lex 

p o sitio n in g type of n u m e ric a l con trol.

The cu rre n t ad van ced sta te of au to m atic p ro g ra m in g h as been due 

in la r g e m e a su r e to the continuing e ffo rts of the u s e r s and p ro d u c e rs of the 

n u m e ric a lly co n tro lled m ach in e tool and co m p u ter. A t the p r e se n t tim e,

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n u m erou s sy ste m s a r e a v a ila b le , including the w ell advan ced and w idely u sed 

A u to m atically P ro g ra m m e d T ool S y ste m (A P T ), la r g e ly developed by the 

A e ro sp a c e In d u strie s A sso c ia tio n on the b a s is of e a r lie r w ork sta rte d at M IT 

under co n tra ct to the U. S. A ir F o r c e .

The p o s sib ility of extending the p rin c ip le of n u m e ric a l con trol to oth er 

types of prod u ction m ach in e ry is a lso being te ste d . O p eratio n s m o st freq u en tly 

m ention ed a s a lr e a d y bein g su c c e s s fu lly adapted to th is type of co n tro l include 

d ra ftin g, a sse m b ly in g , riv etin g, w elding, in sp e ctin g , te stin g , tube fo rm in g, 

m oldin g, w ire w rappin g, and ste e l ro llin g . In th ese ap p lic a tio n s, tap e s o r 

c a r d s , on which n u m e ric a l d ata about the d im e n sio n s, seq u en ce and tim in g of 

o p eratio n s a r e re c o rd e d , a r e u sed to con trol p rod u ction equipm ent. N u m e ric a l 

co n tro l thus h as fa r - r e a c h in g im p licatio n s fo r oth er o p eratio n s in m etalw o rk in g 

and fo r oth er in d u strie s.

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Chapter 3. Status of Numerical Control Applications

N um erically controlled machine tools are used at present only to a 

limited extent. They are being accepted increasingly, however, a s a p r a c ­

tical method in m etalw orking in dustries.

Number Shipped

Although the number of num erically controlled tools is still r e la ­

tively s m a l l - - l e s s than 1 p ercen t of the total num ber of m achine too ls 

installed--the number in creased m arkedly in recent y e ars. Approxim ately 

64 percent of the total was shipped in 1962 and 1963. The number of all 

types, shipped to dom estic u se rs between January 1954 (the first year of 

com m ercial prototype usage) to Decem ber 31, 1963, totalled 3,365. (See 

table 1.) An additional 611 units w ere reported on o rd er, including a sm all 

number for export. These figures were reported to the Department of Com ­

m e rc e by m etalw orking equipment p ro d u cers. A total of 60 com panies r e ­

ported shipments of num erically controlled equipment in 1963.

In the A m erican M achinist 1962 survey of a national inventory of 

m ach in e to o ls, about 4. 5 percen t of a ll co m p a n ies respondin g re p o rte d h a v ­

ing n u m e ric a l con trol, c o m p a re d to 1. 5 p ercen t in a s m a ll study m ad e in 

I960.

T ab le 1. D o m e stic Shipm ents of N u m e ric a lly C on trolled 

Machine T ools, Selected Y ears 1954-63

Period Number Percent 

of total

Total, 1954-63_______ 3, 365 100. 0

1954-58 _____________________ 181 5. 4

1959__________________________ 178 5. 3

I960................................. ................. 366 10. 9

1961__________________________ 496 14. 7

1962________ ______ __________ 997 29. 6

1963.............................. ......... ......... 1, 147 34. 1

Source: U .S. Department of C om m erce, Bureau 

of the Census and B u sin ess and Defense Serv ices A dm in istration.

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Types of N um erical Control Used

Drilling m achines lead the list of specific types of num erically 

controlled machine tools shipped, accounting for 47 percent of the total 

(table 2). They a lso co m p rise about half of those on o rd er.

The next m ost numerous type is the boring m achine, with about 

18 p ercen t of the to tal. The m illin g m ach in e, the f i r s t to be ad ap ted to 

num erical control, constitutes the third m ost important type com prising 

15 p e rce n t. L a th e s accoun ted for about 11 p ercen t of the totah

About 9 p ercen t of a ll n u m e ric a lly co n tro lled to o ls re p o rte d by the 

Department of C om m erce’s survey of shipments are in the m iscellaneous 

category, including grinding and polishing m achines, punching and shearing 

m achines, and certain types of m etal-form ing tools such as p r e sse s, 

fo rges, and bending m achines.

Some types of m etalworking operations are considered le ss suitable 

for application of num erical control because of certain technical difficulties. 

Abrading or grinding, where surface dim ensions m ust be m easured, are in 

this category. A lso, certain sim ple m etalcutting tools such a s saw s and 

polishing and threading m achines are le ss adaptable to num erical control.

The Com m erce Department survey categorized num erically controlled machine tools under three headings: point to point positioning (as 

d e scrib e d above), accounting for over 66 percent; continuous path type, 

c o m p risin g about 12 p ercen t; and the dial or plu gb o ard type; accounting for 

about 20 percent. The latter type c o n sists of m ach in es equipped with n u m eric a l p r o g r a m control s y s t e m s in which ’’p o sitio n in g ” or ’’continuous path ” 

are autom atically commanded by num erical p rogram s fed into the system s 

by m eans of dials, plugs, or sw itches, or by playback of prerecorded 

operations p ro gram s.

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Table 2. Number of N um erically Controlled Machine 

T ools Shipped and on O rder, by Type, 1954-63

Number of m achines

Type Shipped (1954 to 

D ecem ber 31, 1963)

On o rd e r

(D ecem b er 31, 1963)

T otal _ . _ 13, 583 1611

By type of machine:

Drilling m achines 1,690 271

Boring m ach in e s _______________ 636 126

Milling m achin es _______________ 540 78

L a th e s . .. _ . _ _ 402 91

Grinding, polishing, and

other . _ 315 45

By type of num erical control:

Point to point positioning 2,478 374

Continuous path _. ... _ 441 132

D ial or plu gb o ard type r ..... _ 664 105

1 Includes export sh ip m en ts. Inform ation not a v a ila b le on sh ipm ents 

by type of N /C to dom estic u se rs only.

S o u r c e : U .S . D epartm ent of C o m m e r c e , B u r e a u of the C en su s and 

B u sin ess and Defense Serv ices Adm inistration.

Applications in Metalworking Industries

N um erical control appears to be adaptable to operations in a wide 

range of m etalw orking in d u stries. About 55 percent of the n u m erical con ­

trolled tools shipped went to six industries: a ircraft, m etalworking m achinery, general industrial m achinery, special industrial m achinery, machine 

shops, and construction equipment. But at least one tool was shipped to 

every m a jo r m etalw orking industry. (See table 3. )

N um erical control is particularly adaptable to the aircraft and 

m achinery industries and these industries will probably rem ain the m ost 

important u se rs. Plants in these industries typically m anufacture sm all 

batches of a wide variety of p arts, and tooling tim e constitutes a high 

proportion of the total cost of production.

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T a b le 3. D istrib u tio n of M a n u fa c tu r e r s ' Sh ip m en ts of N u m e ric a lly C o n tro lle d M ach in e T o o ls , by M a jo r

In d u stry G ro u p , by T y pe of C o n tro l, 19 5 4 -6 3

S h ip m en ts

D e s c r ip tio n

T o ta l 

n u m b e r, 

1954-63

N u m b er w ith 

p oin t -to -p o in t 

p o sitio n in g 

c o n tr o ls

N u m b er w ith 

co n tin u ou s 

path 

c o n tro ls

N um b er with 

d ia l o r p lu g b o a rd 

type o r 

p r e r e c o r d e d 

m o tio n p r o g r a m

c o n tro ls

T o t a l-------------------------------------------------------- 3 ,5 8 3 2 ,4 7 8 441 664

O rd n an ce an d a c c e s s o r i e s ------------------------------ 135 75 43 17

P r im a r y m e ta l in d u s t r ie s , t o t a l--------------------- 29 0 C) (*)

F a b r ic a t e d m e ta l p r o d u c ts , t o t a l ------------------- 273 191 35 47

M e ta l c a n s ; c u tle ry , hand to o ls , and

h a r d w a r e ------------------------------------------------

H eatin g a p p a r a t u s , s t r u c t u r a l m e ta l

127 ("

(

p r o d u c ts , s c r e w m a ch in e p r o d u c ts , m e ta l (

sta m p in g s ----------------------------------------------

F a b r ic a t e d w ire p r o d u c ts , not e ls e w h e r e

103 ( 191 

(

35 47

c l a s s i f i e d , fa b r ic a t e d m e ta l p r o d u c ts , 

not e ls e w h e r e c l a s s i f i e d -------------------------- 43

(

(_

M a c h in e ry , e x c e p t e l e c t r ic a l, to ta l -------------- 1 ,5 4 3 1 ,1 8 9 93 261

E n g in e s and t u r b i n e s---------------------------------- 94 (" >1

F a r m m a c h in e ry and e q u ip m e n t----------------- 52 | 586 C o n stru c tio n and lik e e q u ip m e n t----------------- 171

M e ta lw o rk in g m a c h in e r y ----------------------------- 490

S p e c ia l in d u str y m a c h i n e r y ------------------------ 221 r > 93 261

G e n e ra l in d u s tr ia l m a c h i n e r y --------------------- 248 ( 419

O ffice m a c h in e s , not e ls e w h e r e c l a s s i f i e d - - 63 ( .

S e r v ic e in d u stry m a c h i n e s-------------------------- 26 | 184 M ach in e s h o p s-------------------------------------------- 178 J

E l e c t r i c a l m a c h in e ry , t o t a l ---------------------------- 335 293 16 26

E le c t r ic d istr ib u tio n p r o d u c t s --------------------- 29 ( '

E le c t r ic in d u s tr ia l a p p a r a tu s (

---------------------

H o u se h o ld a p p lia n c e s ; e le c t r ic lig h tin g and

82

(

w irin g d e v ic e s --------------------------------------- 39 | 293 16 26 R a d io , T V , r e c e iv in g eq u ip m en t ---------------- 12

C o m m u n ic a tio n e q u i p m e n t --------------------------

E le c t r o n ic co m p o n e n ts; e le c t r ic a l p r o d u c ts ,

113 (

(

not e ls e w h e r e c l a s s i f i e d -------------------------- 60 (.

T r a n s p o r a tio n e q u ip m e n t, to ta l --------------------- 859 485 222 152

M o to r v e h ic le s and e q u ip m e n t--------------------- 194 C

A ir c r a f t an d p a r t s --------------------------------------

S h ip s and b o a ts -------------------------------------------

629

19 | 485 222 152

R a ilr o a d e q u i p m e n t ------------------------------------ 17 (_

In str u m e n ts and r e la te d p r o d u c ts , t o t a l --------- 68 55 0 (M

S c ie n tific i n s t r u m e n t s --------------------------------- 31 C

M e c h a n ic a l m e a s u r in g d e v i c e s -------------------

O p tic a l, s u r g ic a l, and m e d ic a l in stru m e n ts;

24

1 55 t1) 0

p h o to g ra p h ic e q u ip m en t; and w a t c h e s------- 13 (.

A ll o th e r, in c lu d in g e x p o r t s --------------------------- 341 C) C) 0

W ithheld to a v o id d is c lo s in g f ig u r e s of in d iv id u al c o m p a n ie s.

S o u r c e : U. S. D e p a rtm e n t of C o m m e rc e , B u r e a u of the C e n su s and B u s in e s s and D e fe n se S e r v ic e s 

A d m in is tra tio n .

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A ircraft industry experts estim ate that num erical control could be 

applied to 20 to 40 percent of all m achining. Making a ir fr a m e s for jet a i r ­

craft req u ires such a technique of machining p arts to m eet the demand of 

high strength to weight and close tolerances. E xperts in this industry 

anticipate a fourfold in crease by 1972 in the number of num erical controlled 

machine tools in use.

A m ajor firm producing electrical and nonelectrical m achinery 

re p o rts that about 50 percent of its m achining operation s a re suitable for 

num erical control applications. This includes machining in job lot production shops, tool and die shops, and repair-replacem en t and parts shops. At 

the p re se n t tim e , this fir m h as ad apted only about 2 p ercen t of its m achining 

to n um erical control. It expects to achieve conversion of all machining 

su itab le for n u m e ric a l control within the next 10 to 20 y e a r s , with an e s t i ­

m ated tenfold in crease in the number of num erically controlled machine 

tools in use.

N um erical control is also being introduced in the m otor vehicles 

and p arts industry, which are the m ajor p u rch asers of machine tools and 

lead ers in development and use of automation m achinery for m a ss p ro ­

duction. An important use is in the fabrication of tooling, including dies, 

needed in op eratin g the in d u stry 1 s highly s p e c ia liz e d m a c h in e s.

Not only is num erical control being adopted by additional firm s and 

industries but once its advantages have been determ ined, some firm s extend 

its applications to a variety of operations. One company producing printing 

m ach in e ry , fo r ex a m p le, u s e s m o r e than 30 different ty pes of n u m e ric a lly 

controlled machine tools. A m ajor multiproduct firm whose various job lot 

m ach in ery producing plants w ere using approxim ately 50 units in 1961, 

reported having about 280 m achines tools with num erical control in the fall 

of 1964.

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Chapter 4. Outlook for Numerical Control

P ro spect for a substantial in crease in sales of num erical controlled 

machine tools in the im m ediate future appears to be favorab le--reflectin g 

the generally favorable bu sin ess outlook in the metalworking sector of the 

economy. Some industry experts expect sales of num erical control to incre a se rapidly over the next few y ears and speculate that by 1967, they 

m ay co m p rise 30 to 50 p ercen t of all m achine tools sold. The p o ssib ility 

of 12, 000 n um erical controlled units by 1967 is also fo reseen . Sev eral 

economic factors m ay affect the outlook.

Supply of Equipment

A variety of num erical control equipment for industry's diverse 

needs is becoming available as the m achine-tool industry gives increasing 

attention to the production and m arketing of this type of machine tool. At 

the 1955 National Machine Tool Show, only seven com panies exhibited such 

equipm ent. In 1964, o ver 50 co m p an ies w ere sellin g n u m e ric a lly controlled 

tools. Among these were the largest m achine-tool producers.

Since m anufacture of num erical control devices involves application of specialized skill and knowledge of modern electronics, m achine-tool 

builders have generally limited them selves to the construction and a s s e m ­

bling of the machine tools them selves, purchasing control system s from 

40 producers or m ore of electronic control equipment. Only about 

12 m ach in e -to o l b u ild e r s a r e cu rre n tly engaged in production of controls 

for their own u se.

Dom estic and world competition m ay induce U .S. producers to 

participate in the m anufacture and m arketing of num erical controlled 

tools to a g re a te r extent than hitherto. Jap an e se and G erm an m achinetool producers have already begun to offer such tools for sale in U .S. 

and foreign m ark ets, but so far only a few units have been sold in the 

United States. Generally, foreign machine-tool producers are behind the 

U .S. in experience and background in num erical control.

Potential Demand

The potential demand for new machine tools, including num erical 

control is a sse rte d by many experts in the field to be high because of 

the high average age of machine tools in use. The m ost recent A m erican 

M ach in ist inventory of m ach in e tools (1963), shows that m o r e than 1. 3 m i l ­

lion units, or 64 percent of the machine tools installed in metalworking 

e sta b lish m e n ts (as c o m p a re d with 60 p e rc e n t in 1958), a r e at l e a s t 10 y e a r s 

old and therefore many are presum ably fully or substantially depreciated and 

subject to replacem ent. Of this number, m ore than 782, 500 fall into the four 

categories of machine tools--drillin g, lathes, m illing, and boring m ach in es-- 

which, at present, are being m ost frequently adapted to num erical control 

(table 4).

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Table 4. Percent of Four Categories of Metal-Cutting Machine

Tools At Feast 10 Years Old, 1963

Category

Total

numb e r

(units)

Tools at least

10 years old

Number Percent

of total

All metal-cutting machine

tools _____________________ 2,137,497 1,364,792 64

Total four categories ____________ 1, 210, 291 782,514 65

Drilling machines ------------------ 446,618 281,524 63

Lathes ________________________ 447, 179 301,037 67

Milling machines ------------------- 236,346 148,546 63

Boring machines ------------------- 80, 148 51,407 64

Source: American Machinist, June 10, 1963.

The potential market for numerical control, on this basis, is not

confined to a few industries but is widely distributed throughout all of

metalworking. In 18 of the Z9 metalworking industries, the number of

overaged machine tools equals or exceeds the national average of 65 percent. Included in the 18 are the construction and mining machinery,

general industrial equipment, farm machinery, and special machinery

industries - -all of which produce primarily in small and medium sized

quantities for which numerical control is considered most adaptable

(table 5).

It is important to keep in mind, however, some limitations in

equating precisely the average age of machinery and the extent of obsolescence. A single unit of a new, more efficient model, for example,

may be equivalent in capacity to a number of older machine tools, some

of which do not lose their economic usefulness and are retained on the

inventory. Furthermore, other old units may be removed from first line

production, but retained for production of spare parts or reserve capacity.

Also, it is not uncommon for companies to rebuild rather than replace an old

machine tool with the current manufactured model. The average age of machine tools may, therefore, rise over time but this does not necessarily

imply that the extent of obsolescence is rising to the same extent.

Market for Numerical Control

Widespread adoption of numerical control depends also on overall

investment plans, either for modernization or expansion; the outlook for

sales, profits, aand taxes; and willingness of firms to scrap obsolete equipment with which they are familiar and which still can be used economically.

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Table 5. Distribution of Four C ategories of Metal-Cutting Machine Tools 

At L e a s t 10 Y e a r s Old, by In dustry, 1963

Industry

M ac h in e t o o l s , 

all ages 1

M achine to o ls, 10 

and over

years

Number

Percent

of

total 2

Number

Percent

of

total2

Percent 

or industry 

total

All metalworking

in d u strie s------------------- 1, 2 1 0 ,2 9 1 100 782,514 100 65

Fabricated m etal p ro d u c ts------ 212,203 18 140,929 18 66

C u t le ry , hand t o o l s , e t c .---- 23,745 2 15,857 2 67

Heating apparatu s--------------- 12,598 1 10,160 1 81

Fabricated structural

m etal products----------------- 41,929 4 27,735 4 66

Screw -m achine products----- 65,569 5 4 3 ,6 9 7 6 67

Metal stam pin gs----------------- 20,621 2 12,908 2 63

M iscellaneous fabricated

m etal products----------------- 33,308 3 21,657 3 65

Other fabricated m etal

p ro d u c ts-------------------------- 14,433 1 8, 915 1 62

Machinery, except electrical— 483,048 40 3 23,408 41 67

E n g in e s and t u r b i n e s ----------- 24,243 2 19,978 3 82

F arm m achinery and equipm e n t -------------------------------- 23,161 2 17,300 2 75

Construction, mining, and

m aterial handling equipm e n t -------------------------------- 45,341 4 34,139 4 75

Metalworking m achinery ----- 107,452 9 66,597 9 62

Special industry machinery— 61,409 5 44,196 6 72

G eneral industrial equipm e n t -------------------------------- 76, 905 6 53,505 7 70

Office, computing and

accounting m achinery ------- 19,649 2 11,787 2 60

Service industry machinery- 19,597 2 14,189 2 72

M iscellaneous machinery,

except e le c tric a l-------------- 105,291 9 61,717 8 59

E lectrical m achinery and

equipm ent---------------------------- 144,902 12 77,424 10 53

E l e c t r i c a l e q u ip m e n t----------- 7 3 ,0 8 5 6 43,357 6 59

Household ap p lian c es--------- 12,815 1 10,628 1 83

Communication and electronic equipm ent-------------- 59,002 5 23,449 3 40

Transportation equipm ent------- 190,560 16 127,154 16 67

Complete m otor vehicles----- 10, 320 1 8, 000 1 78

Automotive p a r ts ---------------- 66, 009 6 46,824 6 71

Complete a irc ra ft--------------- 21, 154 2 13,772 2 65

A ircraft engine and p a r ts---- 84, 754 7 51,352 7 61

Ships and railroad equipment — 8, 323 1 7, 206 1 87

P recision instrum ents and

m e c h a n ism s------------------------- 68,745 6 39,308 5 57

Ordnance and a c c e ss o rie s------- 16, 590 1 11,276 1 68

Furniture and fixtures

(m etal only)-------------------------- 9, 125 1 5, 417 1 59

P rim ary m etal in d u strie s------- 60,521 5 42,807 6 71

M iscellaneous manufacturing

industries ---------------------------- 24,597 2 14,791 2 60

1 The fo ur c a t e g o r i e s of m a c h in e to o ls a r e : d r ill in g m a c h i n e s , la t h e s ,

milling m achines, and boring m achines.

z B e cau se of rounding, columns m ay not add to totals.

Source: American Machinist, June 10, 1963.

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Actual sales of machine tools, a durable good for which purchases

intended for modernization of plant capacity are postponable, fluctuate widely

with business conditions and the outlook in metalworking industries. Since

the postwar peak level of 1952 and 1953 (during the Korean crisis), shipments

of metalcutting machine tools have fluctuated widely. In 1956, shipments

(industrial types with unit values $ 1, 000 or more) were at a peacetime

peak of $834 million. By 1958, the level had fallen by 49 percent, to

$422 million. By 1963, value of shipments had risen to $622 million,

47 percent above the 1958 low but still below the 1956 level. Preliminary

reports for 1964 indicate a 28-percent increase over 1963. Reasons

given for the depressed state of machine-tool sales until recently include

the large unused metalworking capacity, increasing use of plastics, and

the substitution of other types of metalworking processes for metalcutting.

Machine-tool sales are expected to continue to increase over the

next few years. A Department of Commerce estimate indicates a substantial increase in shipments in 1965 over 1964. According to the 1964

McGraw-Hill report on industry’s capital spending plans, metalworking

industries planned significant increases in expenditures for plants and

equipment. Expenditures were to rise by about 22 percent, from $4. 7

billion in 1963 to $5.7 billion in 1964. All metalworking industries except aerospace planned increases. (See table 6. ) Preliminary plans for

the 1965-67 period indicate a continued high level of investment in these

industries. The major part of planned spending is for replacement and

modernization of machinery and equipment.

Table 6. Capital Spending Plans of Metalworking

Manufacturing Companies, 1964-67

(Billions of dollars)

Metalworking

industries

Actual,

1963

Planned Preliminary

plans, 1965-67

1964

Percent

change

from

1963

Annual

average

amount

Percent

change

from

1963

Total _____________ 4. 70 5.71 + 21.5 5. 64 + 20. 0

Machinery --------------------- 1. 24 1.40 12. 9 1. 30 4. 8

Electrical machinery---- . 69 .71 2. 9 . 76 10. 1

Autos, trucks, and parts— 1. 06 1.61 52. 9 1.66 59. 6

Aerospace --------------------- . 39 . 38 - 2. 6 . 35 - 7.7

Other transportation

equipment _____________ . 14 . 18 28. 6 . 15 7. 1

Fabricated metals ---------- .90 1. 11 23. 3 1. 15 27. 8

Instruments ------------------- . 28 . 32 14. 3 . 27 - 3.6

Source: 17th Annual Survey of Business Plans for New Plants and

Equipment, 1964-67. McGraw-Hill Co. , Department of Economics.

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Information is not available on specific plans for purchasing numerically controlled machine tools. The McGraw-Hill reports, however,

cover expenditures for all automated machinery--defined as the "use of

advanced mechanical equipment, especially in combination with selfregulating controls and/or high-speed computers in manufacturing, accounting, distribution, and all other operations.” For metalworking industries, this definition would cover numerically controlled machine tools,

among other types of automated machinery.

Table 7 shows an increase in the proportion of spending for automated machinery from 1959 to 1963 in each metalworking industry. Since

the total amount of capital spending by these industries has been increased

markedly, the increase in the amount for automated equipment (some part

of which is presumed to be N/C) becomes even more significant.

Table 7. Spending for Automated Machinery^1 by

Metalworking Industries, Selected Years

Industry

Percent of total

capital spending

1959 1963 Expected,

1964-67

Machinery ----------------------------------- 9 18 17

Electrical machinery ------------------ 18 36 38

Autos, trucks, and parts ------------ 18 23 28

Other transportation equipment—

Fabricated metals and

4 14 12

instruments ____________________ 6 15 15

1 For the purpose of this survey, automation was defined as nthe

use of advanced mechanical equipment, especially in combination with

high-speed computers and other self-regulating controls in manufacturing, accounting, distribution, and all other operations. n

Source: 17th Annual Survey of Business Plans for New Plants

and Equipment, 1964-67. McGraw-Hill Co., Department of Economics.

Government Programs

Recent Government tax and procurement programs providing special

stimuli to industrial modernization probably have an important effect on the

outlook. Two measures--7 percent income tax credit for new investment in

machinery and equipment and accelerated depreciation rules--are intended to

increase the attractiveness of investing in new equipment. These actions were

designed partially to encourage capital expenditures for modern machine tools,

including numerically controlled units.

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Furthermore, the Federal Government is continuing its purchase of

numerically controlled machine tools. The U. S. Air Force, for example, is

planning a modernization program that is expected to replace a large number

of conventional machine tools with numerically controlled units by 1971.

This and similar programs will result in placing a substantial number of

such machine tools into weapon plants, naval shipyards, air force depots,

and numerous private plants working on defense contracts.

Price and Demand

Because of the larger capital outlays needed to install numerical

controlled machine tools compared to conventional tools, many firms, particularly small ones, may be cautious in purchasing numerical control.

Table 8 shows average unit values of machine tools shipped between 1954 and

1963, ranging from $31, 200 for drilling machines to $160,800 for milling

machines, with the overall average at $77,800. The cost of controls constitute about 3 0 percent of the average total value. Prices for specific models

of numerically controlled machine tools, however, can range from under

$ 10, 000 for a drilling machine to as high as $650, 000 for a multi-axis

milling machine. And the price of the continuous path type of control of a

milling machine can be many times that of a positioning type of control of

a drilling machine.

Table 8. Value of Shipments and Average Unit Values of

Numerical Controlled Machine Tools, by Type, 1954-63

Type of

tool

Number

Total ^

(in thou

of dol]

ralue

isands

.ars)

Average unit values

(in thousands of dollars)

Machine

tools and

controls

Controls

only

Machine

tools and

controls

Controls only

Amount

Percent

of

total

All types__ 13,583 278,917 83, 900 77. 8 23.4 30. 1

Drilling ________ 1,690 52,648 20,031 31. 2 11.9 38. 1

Boring _________ 636 65,549 20,350 103. 1 32. 0 31. 0

Milling ________ 540 86,839 30, 192 160. 8 55. 9 34. 8

Lathes _________ 402 22,483 8, 387 55. 9 20. 9 37.4

1 Include domestic and export shipments.

Source: U. S. Department of Commerce, Bureau of the Census

and Business and Defense Services Administration.

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A more rapid diffusion of numerical control is expected as high

development costs cease to influence prices; as economies of larger scale

production of numerical control equipment permit reductions in their manufacturing costs and prices; and as a larger variety of more simplified, less

expensive machine-control models become available. Recently a few simplified models of several types of N/C machines have become available at

lower prices, and as a larger variety of models are marketed this may

increase.

One factor governing the demand for numerical control is the

minimum rate of return that industry requires for investment in new

equipment. According to a 1964 McGraw-Hill survey, about half of the

companies in metalworking industries answering reports indicated that

they needed a minimum return (before taxes) of 20 percent or more for

replacement and modernization expenditures. The proportion specifying

20 percent or more ranged from 45 percent of the companies in the automobile industry to 62 percent of the companies in aircraft and other

transport equipment. Under these conditions, it may be calculated that

an expenditure of $77,800 (the average value of numerical controlled

machine tools), would need to yield annual savings over a 5-year period

at least equivalent to 2 to 3 man-years of employment (estimated at

$6,400 per man-year). This calculation does not take into account costs

incurred in establishing programing, maintenance, and other indirect activities. Although expressed in terms of laborsavings, the return can

also be realized through savings from other sources.

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Chapter 5. Impact on Labor Requirements Per Unit of Output

Among the possible economic implications of numerical control are

reductions in labor requirements per unit of output, in operating economies,

and in savings in capital investment per unit of output.

Reduction in Unit Labor Requirements

A review of published reports on the experience of users of numerically controlled machine tools shows substantial reductions in unit labor requirements in machining operations. Examples from various industries of

reported applications and some description of the savings achieved, ranging

from 25 to 80 percent are shown in table 9. Aerospace and other metalworking firms report large savings in the machining of complex parts where contours require the continuous path type of control. Significant laborsavings

are also reported by firms using the positioning type of numerical control

to produce parts of relatively simple design in small quantities.

The amount of savings in any particular case depends upon such

factors as specific design of parts, quantity of parts produced, ingenuity of

management and types of machine tools formerly used. Estimates of

savings, therefore, vary over a wide range. Although complete measurement of all the advantages of numerically controlled over conventional machine

tools is not possible, the available data from a large number of cases indicate that average savings in labor requirements per piece were substantial.

Laborsavings come from various sources. Tooling and setup time

is significantly reduced because of the substitution of the tape controls for

conventional jigs and fixtures. Numerically controlled machining is more

continuous since the machine-tool operator does not have to check and recheck against blueprints. Tool operation, moreover, is more uniform

since the operator need not slow up as the work approaches completion.

Since numerical control results in more accurate machining, less work has

to be redonec While equipment maintenance reportedly required more labor

time, the increase was rarely sufficient to offset reported operating

laborsavings.

Laborsavings in machining operations as a result of numerical control are not necessarily reflected in commensurately reduced unit labor requirements for the metalworking plant as a whole. Numerical control does

not affect the entire machining operation, but is usually limited to boring,

drilling, etc. Finishing, grinding, etc. , are usually not done by numerical

control. Moreover, machining is only one of many operations in such plants.

A Bureau of Labor Statistics study of the electronics industry shows that

machining occupations comprised about 20 percent of the total production

worker employment in the defense sector in 1962. Materials handling,

assembling, inspection, finishing, and shipping absorb a major part of the

employment and labor time in electronics and other metalworking plants.

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Table 9. R eported Labor and Other Cost Savings of N u m erically C ontrolled V ersu s Conventional M achining

Industry Machining operations and type of 

num erically controlled machine tool

Reductions in 

labor requirem ents Other resulting economies

A ir c r a f t----------------------- Eleven separate machining op erations including m illing, boring, drilling, 

tapping, and spotfacing on each of 35 

partso Multipurpose (m ill, drill, bore, 

etc. ) machine.

Reduced number of 

m achine-tool operators 

from 5 to 1.

Replaced 5 conventional machine tools. 

Reduced number of jig s and fixtures from 5 

to 1. Total cost per part reduced about 10 

percent.

A ir c r a f t----------------------- Two num erically controlled turret 

d rills for aircraft engine parts such as 

carb u reto rs, fuel pumps, and fuel 

regu lators.

50 percent reduction in labor co sts.

Cut scrap lo sse s by 13 percent.

Lowered overall tooling cost by about 40 

percent. Downtime for design changes 

reduced to tim e needed to program and 

splice tape instead of lengthy period fo rm erly needed to rebuild or build fix tu res.

E le ctrical equipm ent------- Milling and grinding of 3 dimensional steam turbine buckets on num erically controlled profiling machine.

Saved 78 m an-hours 

in machining tim e per 

piece.

Reduced lead time from 144 hours to 

24 hours or 83 percent.

E le ctrical equipm ent------- Drilling 109 holes in a printed 

circuit board.

43 percent reduction in direct labor cost.

Saved 82 percent in tooling co sts. 

Elim inated hand-feed drilling of hole 

patterns.

Machine t o o l----------------- Num erically controlled versus 

tra c e r lathe to face, turn, and bore lot 

of 12 p arts.

Setup and machining 

labor costs reduced by 

57 percent per part.

Tooling cost, including program ing 

cost, reduced by 55 percent.

Auto p a r t s-------------------- Drilling over 100 different p atterns of holes in suspension brackets.

57 percent saving in 

cost per unit.

Elim inated use of fixtures and hole 

pattern plates; and storage, maintenance 

and setup of sam e.

Machine t o o l----------------- D rilling, m illing, facing, tapping, 

and spotfacing of motor base on 

num erically controlled multipurpose 

machine in lot size of 15.

Reduced number of 

m achine-tool operators 

from 6 to 1. Total m a ­

chining time reduced by 

65 percent, from 1.86 to 

0.65 hours per part.

Replaced 6 conventional m achines. 

Cost of tooling reduced from $2, 350 to 

$835.

Special m a c h in e ry ---------- Boring, drilling, and tapping of 

328 holes in each of 9 p arts on num erically controlled boring m achines.

Machining time 

reduced to 1/4 of form er 

tim e.

Total cost reduced from $389 to $90 

for 9 p arts, with tolerances held to 0. 001 

inch.

Sources: V arious trade publications.

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Numerical control reportedly resulted in laborsavings in such operations

as assembling and inspection because of greater consistency of quality

and reproduction, but such savings are not necessarily commensurate with

those in machining.

The implications of numerical control for productivity advances in

metalworking industries as a group are difficult to determine. Speed of

adoption by individual firms and growth in proportion of production to which

numerical control is applied will affect industrywide trends. (Because of

the diversity of production, numerous changes in product design and related

factors, it is difficult to construct valid indexes of output per man-hour for

metalworking industries. )

Operating Economies

Certain operating advantages of numerical control, for which statistical data are difficult to compile, are almost always cited by users and

producers to justify its use. Scrap and inventories of jigs and fixtures are

reduced, resulting in cost and space savings. Because they can produce

small quantities--quickly and economically-- some users report that they

are able to reduce inventory of spare parts. Another important advantage is

the possibility of producing cheaply and quickly intricately designed shapes

to very close tolerances. Numerical control thus allows much greater freedom in design of parts and products formerly too costly to manufacture are

now practicable. Experts in the aerospace industry claim that some parts

used in space equipment are impossible to make without numerical control.

Finally, the shortening of leadtime in production is particularly advantageous, for example in aerospace work, because it affords opportunities to

incorporate last minute design changes in a fast changing field.

Savings in Capital Requirements

Although outlay for a numerically controlled machine tool is generally higher than for conventional tooling, capital expenditure per unit of

capacity is probably lower. Lower unit capital requirements result from

greater utilization of productive capacities, reduced idle time for equipment

in making changeover to different parts, and reduced need for plant space.

However, since capital savings are realized only if the equipment is fully

utilized, ability to plan a continuous flow of small job lot production becomes

essential. Hence, a higher degree of managerial efficiency and improved

plant organization, as much as engineering efficiency, become important in

realizing the potential savings in capital requirements per unit of output.

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Machine tool operator monitoring 

a numerically controlled milling 

machine performing under the 

automatic control of coded tape 

instructions.

Machine tool operator loading 

a part on a numerically 

controlled machine tool capable 

of automatically selecting proper 

cutting tool and performing a 

continuous series of milling, 

drilling, boring and related 

operations.

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Chapter 6. Changes in Occupational Requirements

Because numerical control is a new field where procedures in

most of the operations still are being developed, occupations, job titles,

and duties do not yet follow a well-defined pattern. Some broad tendencies, however, can be outlined. Implications for occupational requirements can be discussed under three types of changes reported by u sers--

changes in relative importance of the various metalworking operations,

creation of a new occupation, and changes in content of old jobs.

Greater Importance of Planning and Programing

The use of numerically controlled machine tools, in general, still

requires the operations found under conventional machining--part design,

methods planning, tooling, setup, and machine-tool operation. But these

operations are performed somewhat differently and are changed in their

relative level of importance as control activities in the machining process.

Table 10 presents the types of operations required and describes, in general

terms, the flow of work.

Tooling, setup, and machine-tool operation are substantially less

important as critical production decisionmaking activities under numerical

control. Virtually all of the functions of developing control data and instructions of these operations are now transferred to the planning stage and programing. Maintenance usually becomes more important not only because of

the more complex equipment but also because to be economical and to result

in adequate return on the higher capital investment, a numerically controlled

machine tool should run the maximum possible hours without breakdown.

Numerical control still requires the same function of design engineering but permits more freedom in the design of the shape and dimensional

tolerances of parts. Some programing systems require conversion of conventional blueprint dimensions into cartesian coordinates; others are used

with conventional drawings without any dimensional modifications. But in

the future, the time consuming task of conventional drawing (blueprint) may

be eliminated, since precise visual representation of the part to be manufactured is not necessary. For positioning control systems only a sketch

containing dimensions in cartesian coordinates could be substituted. For

control systems used in conjunction with computers, various computer oriented techniques of design are actively being worked on to greatly simplify

the transmittal of design information.

Table 11 presents examples from published case studies illustrating some of these changes in terms of comparative man-hour requirements.

Although planning and programing result in increased man-hours, they are

usually more than offset by the reduction of man-hours in the other operations, particularly tooling, setup, and machine-tool operation.

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T a b le 10. O peration al F low Under C on ventional and N u m erica l M achine T o o l C on trol

O peration Conventional N u m erical control

D esign and draw ing of 

p a rt.

P rese n tatio n of engineering data in form of 

draw ing of p art with dim ensions e x p re sse d in conventional blueprint form .

C onversion of engineering blueprin t data in 

fo rm of sketch of p art with dim en sion s e x p re sse d in 

rectan gu lar coordinate fo rm .

Planning of m eth od s. Selection and gen eral d e scrip tio n of m ach in ­

ing op eration s and tooling. P rep ara tio n of 

ge n e ra l setup in stru ction s.

Selection of p a rts or portion of p a rts fo r n u m eric a l control m achining and gen eral d e sc rip tio n s of 

m achining op eration s and tooling.

T o o lin g ----------------------- D esign and fab rication of jig s and fix tu r e s---- D esign and fab ricatio n of jig s and fix tu re s.

P r o g ra m in g ----------------- P ro gram in g is not done under conventional 

co n trol.

P rep ara tio n of m an u scrip t and control ta p e s.

U se of com puter a s aid fo r continuous tape control. 

P rep ara tio n of sp ecific setup in stru c tio n s. (D eterm ining and coding detailed m an ufacturing ste p s and 

in stru ctio n s which d e sc rib e in sequence exact cutting 

o p eratio n s, m achine m otions and functions such a s 

fe e d s, sp e e d s, and direction and d istan ce of table 

t r a v e l.)

M achining m achine-tool 

setup.

Planning and setting up c o rre c t sequence of 

m achining operation s according to blueprin ts or 

other gen eral in stru ction s. Selection and m anual 

adju stm en t of sp ee d s, fe e d s, d irection and d i s ­

tance of table tra v e l and other m achine co n tro ls. 

Mounting tooling.

Mounting tooling and control tape sp ec ified by 

setup in stru ctio n s.

M achine-tool o p e r a tio n -- Loading w orkpiece into m achine. Tending 

and adjustin g m achine during w ork c y c le e Unloading w orkpiece.

Loading w orkpiece into m achin e. Tending and 

ob serv in g the m achine during w ork cy cle. UrTloading 

w orkpiece.

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Table 11. Three Comparative Case Studies of Man-Hour Requirem ents: Conventional

and Num erically Controlled Machining

Case Study 1. Multiple operation of drilling, reaming, and tapping, 914 p arts.

Operation

Conventional

methods

Num erical

control

Percentage 

difference 

in m an-hours, 

num erical 

control vs. 

conventional

Manhours Percent Manhours Percent

T otal ---------------------------------------------------------- 3, 424 100. 0 818 100. 0 -76. 1

Planning ______________________________________________ (na) (na) (na) (na) (na)

Tooling ______________________________________________ 485 14. 2 83 10. 1 -82. 9

Design ____________________________________________ 149 4. 4 15 1. 8 -89. 9

Fabrication ----------------------------------------------------- 336 9.8 68 8. 3 -79.8

Program ing (control data and tape preparation) ________ 0 0 16 2. 0 -

Machining (machine-tool setup and operation) __________ 2,939 85. 8 735 89.9 i

o

Source: U. S. Army, Ordnance Weapons Command, Ordnance Corps Study of Num erically Controlled 

Machine Tools (Joliet, 111. , H eadquarters Ordnance Weapons Command, I960), p. 32.

Case Study 2. Skin m illing, 4 p arts.

Operation

Conventional

methods

Num erical

control

Percentage 

difference 

in m an-hours, 

num erical 

control vs. 

conventional

Manhours Percent Manhours Percent

Total ___________________________________________ 6, 848 100. 0 3, 249 100. 0 — 5 2 o 6

Planning ------------------------------------------------------------- 320 4. 7 960 29.5 200. 0

Tooling ------------------------------------------------------------- 5, 952 86. 9 1,896 58. 3 -68. 1

Design _____________________________________________ 912 13. 3 216 6. 6 -76. 3

Fabrication _______________________________________ 5, 040 73. 6 1,680 51. 7 -66. 7

Program ing (control data and tape preparation) ---------- 0 0 321 9.9 -

Machining (machine-tool setup and operation) ------------- 576 8.4 72 2. 2 -87. 5

Source: Tilton, P eter D. , Retrofit Applications of Num erical Control for Machine T o ols, (Calif. ,

Stanford Research Institute, 1957), p. 61.

Case Study 3. Drilling, 40 p arts.

Operation

Conventional

methods

Num erical

control

Percentage 

difference 

in m an-hours, 

num erical 

control vs. 

conventional

Manhours Percent Manhours Percent

T otal ___________________________________________ 41.8 100. 0 20. 0 100o 0 -52. 2

Tooling _______________________________________________ 27. 1 64.8 12. 7 63. 5 -53. 1

Design _____________________________________________ 2. 7 6.4 2.7 13. 5 0

Fabrication ----------------------------------------------------- 24.4 58.4 10. 0 50. 0 -59. 0

Program ing (control data and tape preparation) ---------- 0 0 1. 2 6. 0 -

Machining (machine-tool setup and operation) ------------- 14.7 35. 2 6. 1 30. 5 -58. 5

Source: Friden Flexow riter for Num erical Control (Rochester, N. Y. , Friden, Inc. , 1961), p. 22.

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Part Programer

Part programers determine the detailed manufacturing steps and

instructions which are coded on the controlling tape and command the machine tool to perform automatically and in sequence such operations as

position of work table, change of speeds and feeds and even change of tools.

In effect, many decision, judgment and setup functions required of a highly

skilled, conventional machine-tool operator are shifted to the part programer's job. Since the coded tape instructions are substituted to perform

many of the major functions of jigs, fixtures, and templates--i. e. , locating, guiding, and measuring--programing takes over some duties of tooling

men. Many of the basic knowledge requirements for part programing are,

therefore, similar to these highly skilled conventional machining occupations:

knowledge of cutting feeds and speeds; functions and use of cutting tools and

fixtures; general shop and machining procedures; a thorough understanding

of the various machine tools; and the ability to interpret engineering data,

sketches, and blueprints.

In addition, programers need certain new skills: a thorough

knowledge of the capabilities of numerical control systems and procedures

and methods of programing, including new techniques and languages.

Skilled machinists and tooling men, who have an ability to solve problems

Control tape with punched instructions that automatically command 

a machine tool through the operations of machining the metal blank 

into a finished part.

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by a systematic approach are generally reported to be able to acquire competency in these skills readily. Some companies prefer to employ engineers

as programers, particularly for the more complex contouring control

systems. However, they usually work in collaboration with a skilled exmachinist or tooling man.

Specific requirements for programers may vary with the complexity of the control system. For example, it usually requires less machining

background and skill to program a drilling machine with a positioning control than a continuous path controlled milling machine. On the other hand,

with the continuous path type, computers are almost always used to assist

the part programer in the time consuming, complex and numerous mathematical calculations involved. Initially, a knowledge of college mathematics

was thought necessary. Today, a high school level mathematical background--

arithmetic, extraction of square roots, algebra, geometry, and trigonometry

is reported sufficient for programing both types.

In some large companies, several programers at different levels

of responsibility may work as a team on one problem. A senior programer

may have overall responsibility and may direct junior programers. Junior

programers may be assigned to convert the senior programer1 s completed

manuscript of instructions into the special programing language or code.

For positioning systems, this coded data is almost always converted onto

tape by typist using an electric typewriter equipped with a special keyboard.

Although computers are used in programing and tape preparation

for a continuous path type machine, numerical control does not necessarily

result in creating new electronic computing system jobs. For those users

of numerical control who have computers, the workload imposed upon existing computer operating personnel is only a small fraction of their total work

time and duties. Some companies, however, create the position of full-time

computer programer for numerically controlled machine tools; he specializes

in preparing the necessary computer instructions to process the data prepared

by the part programer.

Changes in Content of Machine-Tool Operator Jobs

Numerical control tends to change, to some degree, the content

and skill requirements of machine-tool operator jobs. The machine operator

working a conventional machine tool is required to setup a machine including

indexing of table or workpiece; select the cutting speed and feed; and keep

adjusting the machine settings to achieve part specifications. Under numerical control, these duties are automatically carried out by coded tape instructions. The operator of the numerically controlled machine tool is responsible

for tending or watching a highly automatic, costly piece of equipment as it

goes through a sequence of operations. He loads the control tape, fastens the

part in the fixture, and verifies finished part dimensions. When finished part

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dimensions do not conform to specifications, or an operating malfunction

occurs, the operator of a numerical control machine is usually required to

notify the supervisor or programer rather than make the necessary adjustments himself.

Some companies assert that setup and control functions of numerically controlled machine operations are transferred largely to the part programer or built into the machines; therefore, less emphasis is placed on the

need for highly skilled machine-tool operators. Nevertheless, the operator

of a numerically controlled machine still must have many of the basic skills

common to an operator under conventional machining. These include, among

others, a knowledge of general shop and machining procedures; the ability to

read blueprints and other engineering instructions; use micrometers and

other measuring instruments of the trade; and have a knowledge of shop

mathematics (fractions, decimals, etc.). (See table 12 describing jobs and

requirements.) In addition, some companies prefer that the operator be

acquainted with programing techniques. Since the machine-tool operator

must learn about and be responsible for the operation of much more expensive equipment, some companies prefer to use highly skilled and experienced

machine-tool operators on numerically controlled tools.

Changes in Maintenance Jobs

For machine maintenance, the electrical, mechanical and hydraulic

skills of the maintenance workers servicing conventional equipment are still

required. The added responsibility and task of handling electronic systems

and servomechanisms emphasizes the need for a knowledge of electronics,

which is generally a new skill for maintenance personnel.

Maintenance functions at some companies are separated into two

categories of jobs--maintenance for the machine tool itself and electronic

maintenance for the control system. At other companies, one maintenance

job category may include servicing both the machine tool and the control

system.

A variety of patterns of maintenance are found. Some firms, particularly small ones with only a few machine installations, find it more economical to have their maintenance men trained to do all the servicing on the

numerically controlled units. Because of traditional differences in maintenance job classifications, sometimes supported by union jurisdictions, some

companies separate the maintenance responsibility for the machine tool from

that of the control system. Other companies report that the basic knowledge

and skill requirements for maintenance of the control system differ quite

markedly from that for maintenance of the machine tool itself and can best be

accomplished by separate maintenance men.

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Table 12. D escriptions of Duties and Knowledge and Ability Required in N um erical Control Positions at One A ircraft Parts Producer1

Job title Description of duties Knowledge and ability

required

Operator: num erically

controlled m illing

m achine, " A " .

Sets up and operates num erically controlled m illing machine where operation

sequences, tooling, speeds, and feeds are established by a program on tape or

cards. Mounts holding fixture to work table; positions and fastens part into fix ­

ture, and mounts cutter. Loads machine control tape and m akes required control

settings. O bserves m illing process and notifies supervision of m alfunctions.

Checks cutter accuracy periodically. Operates machine to a ssist programing p ersonnel in checking control unit for logical e rrors.

Knowledge of num erically controlled machine

operation; m athem atics,

including trigonom etry; interpretation of blueprints

and sketches; machinability

of various m etals; use of p recision m easuring instruments.

" B " ----------- Operates num erically controlled m illing machine after the setup and initial part

has been checked by higher classified em ployee. Duplicates additional parts by r e ­

peating machine cycle. O bserves m illing process and reports any malfunctioning.

A ssists m illing machine operator " A " .

Same as operator " A " ,

except that in blueprint and

sketch reading, only the ability to obtain easily identified

information is required.

N um erical control parts

program er, " A " .

Prepares numerical control machining program s for all types of machined parts

involving undefined contours and varying radii and plans the sequence of machining

operations. Advises on design of holding fixtures. Program s machining by preparing numerical control m anuscript listing the location of reference and transition

points and the commands to move cutter through its path. Calculates location of

transition points and offset from center of cutter to obtain required cut in conform ­

ance with tolerance lim its. M ay consult with machine operators during proof run of

new or revised program s.

High school education and

2 years' experience in both

num erical control programing

and m achine-shop tool planning; thorough knowledge of

m achine-shop practices, m a ­

chinability of m etals, and

cutter speeds and feed rates.

N um erical control parts

program er, " B " .

Same as parts program er " A " , except program ing is lim ited to cutting tool

movements which can be defined by straight lines, constant and/or defined radii.

Same as " A " , except

that 2 years' experience in

num erical control program ­

ing not required.

N um erical control

coordinator.

Analyzes engineering drawings to determine advisability of using tape controlled

machine tools to machine specific parts, tools, loft tem plates, etc. M akes reco m ­

mendations for changes in design to perm it utilization of num erical control p rocess.

Coordinates preplanning information with programing personnel and directs them in

preparation of numerical control manuscript in code form for translation to magnetic

tape. Directs all data processing operations; acts as company representative to

customer companies; checks all program er m anuscripts and schedules operations.

Investigates and makes recommendations on improvement of num erical control sy s ­

tem s and the acquisition of new equipment.

Two years' college training in m athem atics; 2 years'

experience as a machinist,

tool planner, or tool designer;

and 1 year's experience in

num erical control programing.

N um erical control

computer program er.

Analyzes specific problem s, devises program s to accom plish desired results,

and prepares flow chart and machine instructions for the various computer operations required. Devises test program s and makes recommendations for improving

computer techniques. Coordinates program with other personnel. Keeps informed

on new developments in automatic m achine-tool programing on electronic com puters.

Two years' college training in accounting or m athem atics and 2 years' experience in

computing or tabulating.

D escriptions included in this table are based upon information obtained from one company and are not intended to be representative of num erical control job s. Standard descriptions of jobs in num erical control activities may be found in the revised edition of the Dictionary of Occupational

T itles to be published in Spring of 1965.

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Regardless of the organizational patterns of maintenance, companies find that personnel servicing conventional machine tools can easily be

shifted to service the numerically controlled machine. With additional

training, those best adapted to service the control system are reported to

be workers with a background of electrical or electronic experience.

Changes in Tooling Jobs

Requirements for the occupations of tool designer and tool and die

maker are generally not altered although fewer and less complex jigs and

fixtures are needed. New information related to general capabilities, functions, operation, and programing techniques of various numerically controlled machine tools must be learned. The use of this additional knowledge

is necessary primarily to acquire new techniques to perform the usual tooling

functions rather than learn actual changes in functions. As numerically controlled machines replace conventional machines in the manufacture of tools,

jigs, and fixtures; many of the decisions, judgments, shop practices, and

precision machinery functions presently required of these highly skilled

craftsmen will also be transferred to the planning and programing operations

to be coded as instructions on a control tape.

Changes in Drafting and Designer Jobs

The draftsman may have to learn changes in the engineering drawing

system and how to dimension for numerical control; part designers and methods planners must acquire also a thorough knowledge of the capabilities of

numerical control systems and procedures and methods of programing.

The functions and skills of the draftsman and engineer-designer

may be altered considerably as a result of various new methods of automating design being developed in conjunction with numerical control. Clay

model data pickup and digitizing sketches via cathode ray tube input devices

are among the techniques that experts in the automobile and aerospace industries expect to be perfected over the next 5 to 10 years. These techniques

produce a computer-captured model of the shape to be manufactured which

can be converted readily into tape instructions for use on numerically controlled machine tools. When this occurs, it may affect the numbers of draftsmen required in the future. The principal duties of the engineer-designer will

be the selection of design criteria and development of mathematical techniques

for determining optimum design.

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Chapter 7. Training for Numerical Control

Training or retraining of personnel is one of the key manpower adjustments associated with introducing numerically controlled machine tools. Lacking available trained personnel in their own plant or labor market, users, as

a rule, fill positions for numerical control by retraining their own employees.

Assuming an expansion of numerical control--from 3, 3 65 installations

at the end of 1963 to 12,000 at the end of 1967 and a two-shift operation for

each installation--it is conceivable that nearly 52, 000 persons may need to be

trained--one each per shift for operation, maintenance, and programing over

the 4-year period. This would not include professional training for engineers,

managers, and administrators.

Varying degrees of training are needed to prepare employees for the

different tasks. Substantially more training is required for programing and

maintenance than for machine operation. Formal classroom instruction

followed by on-the-job training are generally provided for employees selected

for programing and maintenance. Training for the machine-tool operator and

other positions ordinarily consists of training on the job after a brief period

of familiarization (usually 1 week) and practical demonstrations of the new

equipment.

Company Training for Numerical Control

Formal classroom instruction is often developed and presented by

representatives of the manufacturers of the machine tools and control systems

at their own specially established schools. Instruction is also conducted at

the user plant by equipment producersT representatives or by employees

trained at the producers1 schools. Only a few large user companies in the

aircraft industry have found it expedient, thus far, to establish their own permanent training staff and school.

Courses for part programers emphasize the techniques of programing procedures in conjunction with programing exercises of typically manufactured parts. Courses for maintenance technicians concentrate on teaching

the electronics of the control system--the servosystems and special circuitry

that accompany numerical control.

Formal classroom instruction for programers with a knowledge of

machining and maintenance men with some knowledge of basic electronics

usually lasts less than 5 weeks. But the length of on-the-job training needed

for these and the other occupations varies widely. Some users indicate that

it may take up to 6 months to train a programer and as long as 3 months to

train a machine-tool operator. Simplification of numerical control technology,

programing techniques and design of machine and electronic components reduces the length of this training. As a result of more simplified programing

languages and techniques, for example, some experts assert that a tool designer can be trained to become a competent programer in 2 or 3 weeks of

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working on the job and that a conventional machine-tool operator can learn to

operate a numerically controlled machine tool in 2 to 5 days.

Jobs for positioning systems generally require less training than jobs

for continuous path systems. Length of training, however, also depends on

such factors as educational background and present skills of the person being

trained. In case of a person already possessing machining skills, a relatively

shorter period of retraining is required. But in the case of a young person just

entering the labor market, training for any one job--with the possible exception

of machine-tool operator--amounts to that normally required for the related

conventional machining occupation plus the specialized training in numerical

control.

Implications for Vocational Education

So far the task of training personnel for numerical control has been

undertaken chiefly by the producers and users of equipment, but this type of

training will probably be incorporated ultimately in the curriculum of institutions which give vocational instruction to machining workers. In the case of

machinists, this would mean changes in apprenticeship training courses (reported by machinists in the labor force in 1963 as the largest single type of

training program taken, and accounting for more than one-third of the machinist vocational programs they had taken); and in courses given by high schools,

vocational schools, technical institutes, and the Armed Forces.

Some case examples of various types of training programs for numerical control are presented below. They include an apprenticeship program

at a government metalworking installation; a machinist retraining program cosponsored by a union and a State department of education, and a seminar series

provided by a professional society.

Apprenticeship Training Program

An example of a comprehensive program for numerical control is

one given at a Government metalworking installation well-known for its apprenticeship school. A unique feature is its comprehensive and long-range objective to develop highly skilled, versatile personnel for numerical control. All

trainees are expected to be able to write complete and accurate program sheets

for any job, to diagnose skillfully and efficiently and aid in the repair of any

malfunctioning of a numerically controlled machine tool, and to understand the

basic theory needed to interpret modern technical literature. Eligibility requirements for entry into training include completion of a 4-year toolmaking

apprenticeship course and experience in electrical or electronics work.

The immediate goal of the course was to fill a demand for programers

and maintenance men to service the installation’s newly acquired numerical

controlled machine tools. Long-range objectives include qualifying senior

students of Toolmaker’s Apprenticeship School of this Government metal -

working installation for key technical and administrative positions and to provide future instructors.

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The course provides 320 hours of classroom work over an 8-week

period. Students are provided with text materials and work sheets to be completed in class or at home. Table 13 describes the content of the course. Dailyhomework averages 2V2 to 3 hours. Four hours are allotted for weekly examinations and 4 hours for a final examination.

Twenty-three employees entered training in two classes held during

late 1962 and mid-1963. Between 1963-67, the new material will be incorporated into the program of the Toolmaker Apprenticeship School, although no

change in the length of the present 4-year course is anticipated.

Adult Education for Retraining Machinists

A basic orientation course, sponsored by the California State Bureau

of Industrial Education and the International Association of Machinists, was

established in 1962 to train journeymen machinists in the fundamentals of

machine-control systems. Its aim is to modify and supplement the existing

knowledge and skills of journeymen machinists for competency in the installation, operation, and maintenance of numerical control. Presently being offered

in two of the largest metropolitan areas of the State, the program has been

completed by approximately 300 machinists as of mid 1963.

Particulars of the course were developed by the State Bureau of Education and the unionTs director of education. A manual was prepared especially

to provide current and pertinent instructional materials for a 12-week (a total

of 30 hours) course. The course includes discussion and study of feedback systems; types of sensors, servos, and monitors; and basic use and operation of

amplifiers. It also includes the study of the principles of machine operation,

of control systems and programing, and principles of machine maintenance.

Appropriations provided under the National Defense Education Act of

1958 aided in financing the project. All State aid, including the text, is furnished free to the schools. The only fee paid for the training by the eligible

journeyman machinist is a $ 1 -tuition fee.

Intended only as a pilot program, indications are that the course will

develop into a permanent and broader source of training. Revision of the text

and course is currently being undertaken. In addition to keeping journeymen

abreast of the latest developments, the course could provide an important

source of training for new workers entering the work force.

Professional Seminar Sessions

A professional technical association, the American Society of Tool

and Manufacturing Engineers, provides one of the principal programs for the

continuing education of professional machining personnel--engineers, foreman, technicians--in the fundamentals, problems of usage, and" current development of numerical control.

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T ab le 13. Content of T raining C ou rses on N u m erical C ontrol Open At a U .S . G overnm ent M etalw orking Installation

T itle of cour se

Length of

cou rse in

hours

Content

P rim a ry num ber s y s t e m ------------ 28 G en eral binary num ber system and binary coded d ecim al sy ste m . N um ber

sy stem s based on 8 and 16 also covered .

A lg e b ra ---------------------------------------------- 32 C oncepts of vectors and direction c o sin e s. A lg eb ra ic and graphical m ethods

for solving sim ultaneous equations. C om preh en sive d iscu ssio n of ca rtesia n , polar

sp h erical, and cylin drical coordinate sy stem s and their relation to m achine axis

m o vem en ts.

A nalytic g e o m e tr y ------------------------- 32 M ethods of lin e a r, p arab olic, and circu lar interpolation. Curve fitting m e th ­

ods based on calculus using the sim p lified and p ractical h eu ristic approach.

Switching c i r c u i t s ------------------------- 24 M ath em atical theory applied to e le c tric or electron ic d ev ice s. Explanation of

com p lex switching netw orks using m odern algeb ra.

E le c t r o n ic s --------------------------------------- 44 B a sic electron ic com ponents, including tr a n sisto r s and se rv o m e ch a n ism s.

P ra ctic a l experience with electron ic testin g d ev ice s. Techniques for reading and

analyzing electron ic sch em atic d iagram s such as those asso cia te d with control and

operation of n u m erically con trolled m a ch in es.

E l e c t r i c i t y --------------------------------------- 32 B a sic e le c tric a l com ponents. Techniques for reading and analyzing e le c tric a l

schem atic d iag ra m s.

H ydrau lics and pneum atics - - - - - 44 B a sic units of hydraulic and pneum atic circ u itry . T echniques for locating

defective p arts. Knowledge of J .I . C . sym b ols and the ab ility to read and analyze

hydraulic and pneum atic d iag ra m s, such as those for n u m erically controlled

m a c h in e s.

P ro gra m in g (m achine and

co m p u te r).

84 T rain in g in two p h ases. P hase one involves techniques for w riting p rogram s

for a va riety of n u m erically con trolled m achine to o ls. G en eral d iscu ssion of p ro ­

gram ing ru les for sp ecific m ach in es follow ed by d em on stration s of p rogram s

w ritten by students. P hase two in volves short d iscu ssio n of the role of com puters

in p rogram in g m achine to o ls, including d em onstrations of typical p ro gra m s for

n u m erical control with an evaluation relative to m anual program in g.

S o u rce : T ra in in g M a n u a ls. U .S . G overn m en t M etalw ork in g In stallation .

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Essentially, the program is an orientation, 3-day workshop seminar covering varied types of numerically controlled machine tools. The

program is designed to give engineers an introduction to programing languages and methods, machine capabilities, and management aspects of numerical control. The program is also intended to help train employees of companies just adopting numerical control and employees designated by their

company to study the feasibility of using numerical control in their plant.

The seminars are open to nonmembers of the Technical Society and

participants have included college professors and presidents of firms as well

as machine-tool design, application, electrical design, and project engineers.

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Chapter 8. Implications for Employment

In a sse ssin g the employment im plications of num erical control of 

machine tools, as in the case of any laborsaving m achinery, it is important 

to recognize the difficulty of isolating the expanding and displacing effects 

of this sp ecific technological change from those resultin g from changes in 

m arket demand, location, foreign competition, m e rg e rs, and consum er 

taste. N um erical control, m oreover, affects a wide diversity of m etalworking industries, having different trends of growth and is only one of 

many technological changes affecting p ro c e sse s, m aterials used, and p rod ­

ucts of metalworking industries. Although direct m easurem ent of the m an ­

power im pact is not possib le, som e factors affecting employment can be 

described.

Labor D isplacem ent and Expansion

The extent of labor displacem ent or expansion in metalworking industries depends greatly on the economic circum stan ces of the change and 

speed with which num erical control is introduced. When production is r e latively constant or increasing slowly, the in creased output per man-hour 

as a result of num erical control could result in a reduction in employment. 

The extent of this reduction might be le ss than otherw ise because of the 

plant’s im proved competitive position in the world m arket with fo r ­

eign producers.

Under highly competitive dom estic conditions, it is possible that 

plants with lower costs because of num erical control m ay in crease their 

employment, but at the expense of competing plants or subcontracting (such 

as independent tool and die and machine shops). They m ay thereby gain a 

larg e r sh are of the m arket with the im pact falling on the sm aller and p r e ­

sum ably le ss financially capable plants.

Since the introduction of num erical control is usually gradual— one 

machine tool at a time phased over a period of time— the sm all number of 

w orkers whose jobs are elim inated could probably be tran sferred within the 

plant or com pany to avoid layoff. How ever, if a larg e num ber of n u m erical 

control machine tools are introduced in a short period of tim e, without a 

substantial in crease in production, the ability to tran sfer displaced w orkers 

would becom e m ore difficult and possibly result in layoffs.

During periods of expanding demand, new production peaks might 

be met through use of num erical control without adding as many w orkers as 

might be required with conventional equipment and, therefore, would reduce 

employment opportunities. Where n um erical control is introduced to m an ­

ufacture new item s in demand which could not be produced econom ically 

with conventional machining m ethods, num erical employment would in crease.

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Im plications for Equipment P rodu cers

N um erical control also affects the demand for labor on the part of 

those who produce the equipm ent--m achine-tool builders and m an u factu rers 

of control system s and com puters.

M achine-Tool B uilders. N um erical control could stimulate new 

m achine-tool builders and their sales and employment could, therefore, 

in crease. Employment in the m achine-tool industry (m etal-cutting se g ­

ment) in 1963 a v e r a g e d 6 4 ,4 0 0 , about 1 p ercen t higher than in 1962. B y 

A ugust 1964, the num ber of em ployees had rise n to 71, 100. A re la tiv e ly 

high and unchanged proportion of em ploy ees--31 p ercen t--are ad m in istrative, clerical, and professional.

As demand for num erical control equipment r is e s , however, demand for some types of conventional tools m ay be displaced. Since one 

n u m erical m achine can often do the job of two or m ore conventional tools, 

total unit sales of machine tools m ay be reduced as num erical control b ecom es m ore important. In addition, some m achine-tool builders are using 

this new equipment in their own production. The net result of contracting 

and expansive facto rs on employment is therefore difficult to determ ine.

Control System P rod u cers. N um erical control also opens new 

product and service opportunities for producers of electronic industrial 

controls and therefore m ay create new employment opportunities. These 

firm s are part of the electronics industry and separate employment sta ­

tistics are not available. Control producers find an expanding m arket for 

such elem ents a s tran sducers, relays, com parators, and servom ech an ism s. 

Some of the leading control producers have established special departm ents 

devoted solely to the research , design, and fabrication of num erical control 

system s, not only for machining, but also for applications in drafting, inspection, and assem bly. In addition, integrating the hardw are produced 

into a complete system creates demand for system s engineering personnel, 

including all types of control engineers and technicians.

C om pu ter M a n u fa c t u r e r s . Since it is not g e n e ra lly c o n sid e re d 

econom ical to have a computer solely for the needs of program ing num erical 

control, the effect on employment at computer m anufacturers m ay be n egligible. Com puters are required only for program ing the m ore com plex but 

for le ss num erous continuous path system . U se rs of num erically controlled 

m achines who already have com puters have capacity to handle this added 

task . U s e r s who do not have com puters m ay use the se r v ic e s of outside 

com panies owning com puters or of the data-processin g centers of computer 

m an u factu re r s .

Employment in the Metalworking Industry Group

Em ploym ent in the m etalw orking industries a s a group av eraged

6 .6 m illion in 1964, about 38 percent of total m anufacturing em ploym ent.

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The industry groups covered included ordnance, fabricated-m etal products, 

m achinery, electrical equipment, transportation equipment, and instrum ents 

and related products— industries that use and produce num erically controlled 

tools. Em ploym en t in c r e a se d by 33 p ercen t between 1947 and 1964 com pared 

to an in c r e a s e of 11 p e rce n t for m an u factu rin g a s a whole. The gain w as l i m ­

ited v e r y la r g e ly to the f i r s t 10 y e a r s of the p eriod . Betw een 1957 and 1964, 

the total num ber of em p lo y e e s in c r e a s e d by about 117, 000 or 2 p e rc e n t; e m ­

ploym ent of production w ork ers declined by about 168, 000 or 4 percent. Of 

the six industry groups, only the transportation, industry group did not r e ­

cord an employment gain in this period.

A dm inistrative, profession al, technical, and clerical employment 

in c r e a se d by 111 p ercen t between 1947 and 1964, while production w orker 

em ploym ent in the m etalw o rk in g in d u strie s r o s e by only 14 p ercen t. A c ­

cordingly, the proportion of production w orkers to total m etalw orking e m ­

ployment had declined from about 80 percen t to 69 percen t in 1964. In that 

year, the adm inistrative, p ro fessio n al, technical, and c le ric a l em ployees 

c o m p r is e d 31 p e rc e n t of the total, ranging fro m 23 p e rc e n t in fa b r ic a te d - 

m etal products to 59 percen t in ordnance and a c c e s s o r ie s .

Production w orkers in metalworking industries averaged in 1964 a 

slightly longer workweek than factory w orkers generally (table 14). A verage 

w eekly o v ertim e hours v a r ie d , fro m 1. 8 hours in ordnance to 3. 9 h ours in 

the transportation equipment and m achinery industry groups.

Table 14. A verage Weekly Hours and O vertim e Hours of Production 

W orkers in Metalworking Industries, 1964

Industry A verage 

weekly hours

Average

weekly

overtim e hours

M a n u fa c tu r in g _____________________ 40. 5 3. 1

F a b r ic a t e d - m e ta l p r o d u c ts________ 41. 4 3. 4

M ach in ery _________________________ 41. 8 3. 9

E lectrical equipm en t_____________ 40. 3 2. 3

Transportation equipm ent________ 42. 1 3. 9

Instrum ents and related p ro d u cts. 40. 8 2. 5

Ordnance and a c c e sso r ie s ________ 41. 0 1. 8

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E stim ated rates of output growth over the 1957-76 period prepared 

by the N ational Planning A sso c ia tio n for 18 m etalw orkin g in d u strie s (3-d igit 

SIC) project a fairly high rate of expansion for many industries. (The NPA 

projections are based on the assum ption of a 4. 2 -percent growth rate in the 

g r o s s n ational product. ) Introduction of n u m e r ic a l control in m etalw orkin g 

industries over the next few y ears m ay, therefore, take place under fav o rable econom ic conditions. Of the 18 in d u s tr ie s , the p r o je c te d rate for 

4 would in c r e a s e fro m 2 to 4 p e rc e n t; 8, fro m 4 to 6 p e rc e n t; and 6, 6 p e rc e n t 

and over.

Em ployment, as analyzed by the Bureau of Labor Statistics, is also 

expected to in crease in many of these industries but not as rapidly as output 

because of productivity advances resulting from technical innovations, including num erical control. The extent of employment change which will vary 

from industry to industry is difficult to estim ate. Em ployment in electron ics, 

for exam ple, is expected to in cre ase , but at a slow er rate than in the recent 

p ast. In the aero sp ace industry, em ploym ent m ay continue to decline. Future 

employment trends in the motor vehicles and p arts industry are uncertain.

With m ore than 20 percent of total metalworking employment on defense work 

in 1963, the outlook for metalworking jobs depends to a considerable extent 

on Government policies.

Em ployment Changes in Specific Machining Occupations

W orkers m ost directly affected by the introduction of num erical control are those who set up and operate machine tools. In early 1963, about

1. 1 m illio n w o r k e r s w ere em ploy ed as all-ro u n d m a c h in ists, m ach in e-to o l 

op erators, tool and die m ak ers, instrum ent m ak ers, and setup and layout 

men. (This Bureau of Labor Statistics estim ate includes w orkers employed 

in all sectors— manufacturing and nonmanufacturing. )

Although growth in employment in each machining occupation could 

be slowed by extended use of num erical control, som e occupations m ay be 

affected m ore than others. Since one num erically controlled machine tool 

displaces sev eral conventional m achines, employment of m achine-tool o p e rators is particularly sensitive to change. In early 1963, m achine-tool o p erator employment (skilled and sem iskilled) was estim ated at about 570, 000.

The probable decline of this level of employment will be partially offset by 

the demand for skilled m achine-tool operators as part p ro g ram ers.

The im pact of num erical control on employment of m achinists and 

instrum ent m ak ers (experim ental m ach in ists) is likely to be m ore lim ited.

In e a rly 1963, m ach inist and instrum ent m ak er em ploym ent w as about 350, 000. 

Since many m achinists and instrum ent m akers are employed in metalworking 

repair shops and re se a rc h and development lab oratories where num erical control is not likely to be used extensively, the im pact of this technology on their 

employment m ay be limited.

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Tool and die m akers m ay be affected by w idespread use of num erical 

control. More than 150, 000 tool and die m akers were employed in early 1963. 

According to Departm ent of Labor estim ates, about 35, 000 w orkers will be 

needed during the 1960!s to replace experienced tool and die m ak ers who r e ­

tire or die. Additional thousands m ay be needed as a resu lt of industrial 

expansion. An adequate supply of w o rk e rs, however, are not expected to 

qualify through apprenticeship during the 10-year period, 1960-70. An 

important source for overcom ing such shortages is through the upgrading 

of m achine-tool o p erato rs and m ach in ists. One of the resu lts of the wider 

use of num erical control m ay be to reduce this prospective shortage.

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Chapter 9. Labor-Management Adjustments

P roblem s of job adjustm ent and displacem ent at plants introducing 

num erically controlled machine tools are largely m atters of collective b a r ­

gaining in the m etalw orking in dustries where about 75 percen t of em ployment is covered by union contracts. The principal unions in these industries are the United Automobile, A erospace and A gricultural Implement 

W orkers of A m erica; the International Union of E lectrical, Radio and M achine W orkers; the International A ssociation of M achinists and A erospace 

W orkers; and the United Steelw orkers of A m erica.

This chapter briefly reviews some collective bargaining ad justments to technological change generally, not specifically for num erical 

control. Only illustrative exam ples are given since data on the p re v a ­

lence of such provisions are not available. The introduction of num erical 

control reportedly has had little im pact as yet on labor-m an agem en t r e la ­

tions. N evertheless, som e brief discussion of methods of determining 

skill ratings and wage paym ents, of determining jurisdiction over new jobs, 

and of aiding in the adjustm ent of displaced w orkers is pertinent to this 

analysis of possib le im plications of num erical control.

Method of Determining Skill Level and Wage Rates

One im p o rtan t lab o r-m a n a g e m e n t p ro b le m that a r i s e s in introducing 

num erical control pertains to the determination of levels of skill and wage 

rates for the jobs asso ciated with the new technique.

Collective bargaining contracts generally specify the wage setting 

and job classification procedures governing affected jobs within the b a r ­

gaining unit. Under form al job evaluation sy stem s, new jobs would be p ro ­

cessed according to the criteria set forth in the plan. Where incentive 

plans are in force, the introduction of num erical control m ay entail efforts 

to r e v is e r a t e s . (A ccording to a BL»S study, about 21 p e rce n t of p ro d u c ­

tion w orkers in m etalw orking w ere paid on an incentive b a sis as of 1958.)

Questions m ay a rise under the recognition clause of the contract. 

While experience is still limited, it is reported that operators and m ain ­

tenance w orkers on num erically controlled m achine tools are usually regarded 

as part of the production w orker group covered by union contracts. The 

status of the p ro g ra m e r, on the other hand, h as been under dispute. F o r ex ­

am ple, in a grievance case in an automobile plant that was settled by an im ­

partial arbitrator, m anagem ent argued that work of program ing for num erical control belonged to a production engineer of the methods departm ent, a 

m anagement unit, and therefore was outside the bargaining unit. The union 

countered that many of the functions of program ing had always been part of 

the to o lm a k e r’s activ ities and belong to production w o rk ers in the bargaining 

unit. The arbitrator decided that, under the recognition clause, toolm akers 

could not be totally excluded from perform ing the program ing function since 

this would deprive them of work that they had perform ed previously by virtue 

of their classification .

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As numerical control is extended, grievances over the operation

of provisions in collective bargaining agreements for job classification,

seniority, and wage rate setting for new jobs, may arise more frequently.

Methods of Adjusting to Displacement

In some metalworking firms, labor-management agreements

attempt to cushion the impact of worker displacement by various techniques.

None of these techniques were specifically adopted to cope with the effects

of numerical control but are generally applicable in case of displacement

because of technological or related changes. They would be applicable, for

example, in the case of worker displacement resulting from a plant shutdown because of inability to compete with more highly automated plants. The

introduction of numerical control is part of the general background of technological change that is stimulating labor and management to consider

measures for job security, etc. These measures are described below under

four broad types:

Measures for Advance Notice. In some metalworking firms, labormanagement agreements provide that employees and unions be given notice

of anticipated layoffs, plant closing, and major changes, a fixed period of

time in advance of the effective date of the change. Such advance notice provides opportunity for planning programs of adjustment. The period of time

given may be from 1 month to a year. In a few metalworking plants, joint

union-management committees have been set up to study the effects of automation and recommend methods of adjustment.

Methods of Avoiding Layoff. A variety of methods are used in

achieving technological change without layoff of individual workers. The

exact extent of these practices in metalworking industries is not known.

Some employers make use of attrition to reduce the work force to

the level needed by the new equipment. No one is hired to fill vacancies left

by'death, retirements, and quits. Since numerical control is usually introduced gradually, one tool at a time, and thus affects only a few employees at

a time, the use of attrition may be a particularly effective method of avoiding

layoffs.

Early retirement provides a way of avoiding layoffs where technological change is reducing job opportunities, by encouraging older workers

to leave the work force. Younger workers who might otherwise be laid off

because of technological change can then be retained. A large proportion of

private retirement plans contain provisions for payment of benefits on retirement before 65. Recent agreements in the auto and farm equipments industries liberalized provisions for early retirement benefits.

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Labor-management agreements in some metalworking firms (notably in the automobile and farm equipment industries) provide for transfer of

workers whose jobs have been eliminated to other jobs within the plant or to

other plants within the same company. In a few cases, relocation allowances

covering the cost of moving are provided.

Methods of Easing the Burden of Unemployment. A substantial number of workers in automobile, farm equipment, aerospace, and electrical

machinery industries are covered by severance pay plans, which provide a

lump-sum benefit to workers who are permanently laid off, usually varying

with length of service. Also, in these industries, a substantial number of

employees are covered by plans providing supplementary unemployment

benefits. These payments, made out of a fund financed by employers, are

intended primarily to supplement benefits paid out by the State unemployment

insurance system.

Methods of Facilitating New Employment. Employers and unions

in metalworking industries have sometimes tried to find jobs for laid-off

employees in other companies through newspaper ads, private and public

employment offices, etc. The International Association of Machinists, for

example, located jobs in different parts of the country for several thousand

workers laid off in New York. Some metalworking unions have initiated

retraining programs for displaced worker s. As numerical control is more

widely adopted, retraining programs, along the lines described earlier, will

probably be considered more intensively.

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Appendix. Selected Bibliography on Outlook for Numerical 

Control of Machine Tools

Introduction

Ashburn, Anderson. 1'Automation--Its Development in Metalworking,"

Mechanical Engineering, November 1955, pp. 958-962.

Perkins, Roy B. Evolution of Numerical Control, Paper presented at

Thirty-First Annual Meeting of American Society of Tool and Manufacturing Engineers, Chicago, April 29-May 3, 1963, 14 pages.

Proceedings of the Michigan Machine Tool Conference, March 28-29, 1962.

Edited by Clark E. Chastam. Industrial Development Research Programs,

Institute of Science and Technology, The University of Michigan,

June 1962, Ann Arbor, Michigan.

"The Eight American Machinist Inventory of Metalworking Equipment, 1958, "

American Machinist, November 17, 1958, pp. 1-4.

National Machine Tool Builders’ Association, Machine Tools Today,

Washington, National Machine Tool Builders’ Association, 1964, pp, 1-48.

Numerical Control in Machine Tool Technology

Aerospace Industries Association of America, Inc. , Numerical Control,

Washington, Aerospace Industries of America, Inc. , 1957, pp. 8-25,

47-57.

"Apt-Manufacturing by the Numbers," Aerospace, March 1964, pp. 17-20.

Carlberg, Edward F. Trends and Future Directions of Numerical Control,

Paper presented at Thirty-First Annual Meeting of American Society of

Tool and Manufacturing Engineers, Chicago, April 29-May 3, 1963,

8 pages.

Childs, J. J. "How Air Force Requirements Blazed the Path to Numerical

Control, " Machine and Tool Blue Book, May 1961, pp. 90-93. (Also

issues of June 1961, pp. 132-134; July 1961, pp. 133-136; January 1962,

pp. 118-120; February 1962, pp. 134-135.)

Clark, Jr. , Stephen C. "Numerical Positioning, " Automation, April 1958,

pp. 60-67o

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McCleary, E. L. A Look at the Bright Future of Numerical Control, Paper

presented at Creative Manufacturing Seminars of American Society of

Tool and Manufacturing Engineers, Detroit, 1963-64, 13 pp.

Shallenberger, Frank K. "Economics of Plant Automation, n Automation in

Business and Industry, M New York, John Wiley and Sons, Inc. , 1957,

pp. 547-5750

Stocker, Jr. , William M0 "The ABC’ s of Numerical Control, " American

Machinist, August 8, I960, pp. 93-108.

Taft, Charles K. What is Numerical Control?, Paper presented at ThirtyFirst Annual Meeting of American Society of Tool and Manufacturing

Engineers, Chicago, April 29-May 3, 1963, 14 pages.

"What is N /C ’ s Place in Manufacturing?" American Machinist,

March 19, 1962, p. 106.

Status of Numerical Control Applications

Aerospace Industries Association of America, Inc. , Aerospace Technical

Forecast 1962-1972, Washington, Aerospace Industries of America, Inc.,

1962, pp. 125-126.

"Numerical Control Shows Record Growth, " American Machinist, July 22,

1963, pp. 71-76.

Taylor, Frederick. "Autos in a Flurry," Wall Street Journal, July 17,

1964, p. 1.

U.S. Department of Commerce, Bureau of the Census and Business and

Defense Services Administration, Machine Tools with Numerical and

Prerecorded Motion Program Controls: 1954 - June 30, 1962,

Washington, Bureau of the Census, 1963, pp. 1-4C

U.S. Department of Commerce, Bureau of the Census and Business and

Defense Services Administration, Machine Tools with Numerical and

Prerecorded Motion Program Controls; 1963, Washington, Bureau of

the Census, 1964, pp. 1-3.

Outlook for Numerical Control

"A Survey of Current Equipment and Systems, " Metalworking, December

1962, pp. 25-26.

Hitchcock’ s Machine and Tool Directory, 1962, Hitchcock Publications,

Wheaton, 111. , 1962 edition, 442 pages.

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Jones, H. F. ’’Automation Holds Key to Fast Style Changes, ” The Iron Age,

July 9, 1964, p. 37.

Melman, Seymour. "Machine Tools: A Backward Industry, " Challenge,

June 1962, pp. 27-31.

Metaxas, Ted. "You Can’t Afford to Overlook Numerical Control, " Mill and

Factory, August I960, pp. 79-80.

"Numerical Control: The Second Decade, " American Machinist, October 26,

1964, pp. nc 1-48.

Stocker, Jr. , William M. "How to Prove the Profit in Numerical Control, "

American Machinist, October 30, 1961, pp. 77-120.

17th Annual Survey of Business Plans for New Plants and Equipment, 1964-

1967, McGraw-Hill Company, Department of Economics, New York,

April 1964, 29 pp.

"The Ninth American Machinist Inventory of Metalworking Equipment, "

American Machinist, June 10, 1963, pp. env 1-72.

UoS. Department of Commerce, Business and Defense Services Administration. The U.S. Industrial Outlook for 1963, Washington, U.S. Government Printing Office, 1963, p. 52.

U.S. Treasury Department, Internal Revenue Service. Depreciation Guidelines and Rules, Pub. No. 6156 (7-62), Washington, U.S. Government

Printing Office, 1962, pp. 14-16.

"What’ s Holding Back Numerical Control?" Factory, April 1961, pp. 67-69.

Impact on Unit Labor Requirements

Childs, J. J. "Will Numerical Control Save You Money?" Machine and Tool

Blue Book, October 1961, pp. 132-134.

Friden Flexowriter for Numerical Control, Rochester, N. Y. , Friden Inc. ,

1961, pp. 21-25.

Hale, Frank W. Economic Aspects of Positioning Numerical Control Systems,

West Hartford, Conn. , Pratt and Whitney Co. , Inc. , April 1962, ppc 20-33.

Jollis, C. S. "The Advantages of Numerically Controlled Machine T ools,"

Computers and Automation, March 1961, pp. 15-18.

"Justifying N. C. - Design Flexibility, " Metalworking, January 1962,

pp. 21-23.

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"Justifying N. C. - Layout Eliminated, n Metalworking, September 1962,

pp. 81-82.

"Justifying N. C. - Lower Manufacturing Costs, " Metalworking, March 1962,

pp. 43-44.

Knaus, Jr. , Walter P. and Edgar, Charles T. "Figuring Where N/C Pays

Off, " American Machinist, June 8, 1964, pp. 76-77.

McAvay, William. Numerical Control for Short Run Production, Paper

presented at Thirty-First Annual Meeting of American Society of Tool

and Manufacturing Engineers, Chicago, April 29-May 3, 1963, 15 pages.

"N. C. Can Cut Machinery Costs On Short Run Production, " Metalworking,

March 1962, pp. 45-46.

"N /C : How and When to Buy It, " Steel, May 4, 1964, pp. 3-16.

Randall, Jr. , H. B. "Numerical Control Cuts Production C osts,"

Automation, July 1964, pp. 55-57.

Stanford Research Institute, Management Decisions to Automate, Report

prepared for Office of Manpower, Automation and Training, U. S. Department of Labor, Washington, D. C. , 1964, pp. 20-23.

Tilton, Peter D. Retrofit Applications of Numerical Controls for Machine

Tools, Pasadena, California, Stanford Research Institute, December

1957, pp. 51-76.

"To Evaluate N. C. Economies, Check All Its Benefits, " Metalworking,

December 1962, pp. 21-24.

U. S. Army, Ordnance Weapons Command, Ordnance Corps Study of

Numerically Controlled Machine Tools, Joliet, 111. , Headquarters

Ordnance Weapons Command, I960, pp. 14-43.

Vlahos, C. J. "N /C Makes Giants of Small Manufacturers, " Mill and

Factory, February 1964, pp. 59-62.

Occupations and Training

Bloomberg, Ray. "At Boeing Nearly Everybody Studies Numerical Control, "

Control Engineering, August 1959, pp. 38-40.

"California Classes Boost Journeyman Training," Machinist, May 31, 1962,

p. 11.

Childs, J. J. "Numerical Control and Personnel Requirements, " Machine

and Tool Blue Book, December 1961, pp. 123-126.

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Clarke, Robert E. Methods of Training Plant Personnel for Numerical

Control, Paper presented at Thirty-First Annual Meeting of American

Society of Tool and Manufacturing Engineers, Chicago, April 29-May 3,

1963, 7 pages.

Friden Flexowriter for Numerical Control, op. cit. , pp. 8-11, and 21-23.

Hale, Frank W. The Place of Numerical Control in Vocational Education,

Presented at American Vocational Association Seminar, Milwaukee,

Wisconsin, December 5, 1962, 8 pages.

Heeb, Harry B. "Programming Is Easy for Point to Point Numerical

Control, " Machinery, June 1962, pp. 92-97.

Hyman, I. Harry. "A Toolroom Foreman Talks Training, " American

Machinist, February 6, 1961, pp. 80-82.

"Job Switch for T and D M akers?" American Machinist, November 13, 1961,

p. 119.

Keebler, James C. "Planning and Programing N /C ," Automation,

September 1964, pp. 58-144.

McRainey, J. H. and Miller*, L. D. "Project 60 - Numerical Control, "

Automation, August I960, pp. 70-100.

Monroe, Harry. "Training for Maintenance," Automation, March 1962,

pp. 142-145.

"National Education Act Helps Two Ways, " Control Engineering, August I960,

pp. 77-79.

Olesten, Nils O. "Steppingstones to Numerical Control, " Automation,

June 1961, pp. 60-66.

"Organization of a Numerical Control Operation, " Mechanical Engineering,

May 1959, p. 61.

"School for Maintenance, " Mill and Factory, April 1963, pp. 82-86.

Severson, Thomas V. A User's View of Tape Machines, Paper presented at

Thirty-First Annual Meeting of American Society of Tool and Manufacturing

Engineers, Chicago, April 29-May 3, 1963, 7 pages.

Smith, H. A. "Organizing Maintenance for Numerically Controlled Machines, "

Plant Engineering, June I960, pp. 111-113.

"Tool with Skill of a Machinist, " Business Week, June 17, 1961, pp. 80-87.

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" T r a in Students E a r ly for N /C , M Irdn A g e , Ja n u a r y 24, 1963, p. 43.

"T ravelin g Sem inar A dvises Metalworking M anagement, " A m erican 

M achinist, Febru ary 19, 1962, p. 93.

U. S. A rm y , Ordnance W eapons Com m and. Ordnance C o rp s Study of Nu m e r ­

ic a lly C on trolled M achine T o o l s , Jo lie t , 111. , H e a d q u a rte rs Ordnance 

Weapons Command, I960, pp. 32-54.

"Z e ro in g In on Z ero Downtime, " F a c to ry , Septem ber 1961, pp. 112-116.

Im plications for Employment

Corplan A sso ciate s of Illinois Institute of Technology R esearch Institute. 

T e ch n o lo g ical Change - M etalw orking In d u str ie s, C h icago, 111. , Illin o is 

Institute of Technology, 1964, pp. 43-49, 53-59.

Fulton, Joseph F. "Em ploym ent Impact of Changing Defense P r o g r a m s ," 

Monthly L a b o r R e v ie w , M ay 1964, pp. 508-516.

"Jo b Switch for T and D M a k e r s ? " A m e rican M achinist, N ovem ber 13, 1961, 

p. 119.

Lynn, F r a n k . "M etalw orkin g in 1980, " A m e r ic a n M a c h in ist, D e c e m b e r 9, 

1963, pp. 81-85.

"M achining O ccu pations, " O ccupational Outlook Handbook, 1963-64 E d itio n , 

Bureau of Labor Statistics (Bulletin 1375) Washington, U. S. Government 

Printing Office, 1963, pp. 433-447.

M anpow er R epo rt of the P r e sid e n t and a R epo rt on M anpow er R e q u ir e m e n ts , 

R eso u rces, Utilization and Training by the U. S. Department of Labor, 

M arch 1963, pp. 17-20, 108-109, 163-167.

Labor-M anagem ent Adjustm ents

Bok, Derek and K o sso ris, Max D. Methods of Adjusting to Automation and 

T e ch n o lo g ical C h an ge. R ep o rt p r e p a r e d fo r the P r e s id e n t 's C om m ittee 

on Labor-M anagem ent Policy, U. S. Department of Labor, Washington,

D. C. , 33 pp.

K illin g s w orth, C h a r le s C. "In d u str ia l R e latio n s and A utom ation, " The 

Annals of the A m erican Academ y of Political and Social Science, M arch 

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