Economic Quality Control of Manufactured Product

I. What is the Problem of Controlf H A T is t h e problem involved in t h e control of q u a l i t y of m a n u f a c t u r e d p r o d u c t ? T o a n s w e r this q u e s t i o n , let u s p u t o u r selves in t h e position of a m a n u f a c t u r e r t u r n i n g o u t millions of t h e s a m e kind of thing e v e r y y e a r . W h e t h e r it be lead pencils, chewing g u m , b a r s of soap, telephones or a u t o m o b i l e s , t h e problem is m u c h t h e s a m e . He s e t s up a s t a n d a r d for t h e q u a l i t y of his p r o d u c t a n d then tries to m a k e all pieces of p r o d u c t c o n f o r m with t h i s s t a n d a r d . Here his troubles begin. F o r him s t a n d a r d q u a l i t y is a b u l l s - e y e , b u t like a m a r k s m a n s h o o t i n g at such a t a r g e t , he o f t e n misses. As is t h e case in e v e r y t h i n g we do, u n k n o w n or c h a n c e c a u s e s exert their influence. T h e p r o b l e m then is: how m u c h m a y t h e q u a l i t y of a p r o d u c t v a r y a n d yet b e controlled? I n o t h e r words, how m u c h v a r i a t i o n should w e leave to c h a n c c ? To m a k e a thing t h e w a y we w a n t to m a k e it is one p o p u l a r c o n c e p tion of control. We h a v e been t r y i n g to do this for a good m a n y y e a r s a n d we see t h e fruition of this effort in t h e m a r v e l o u s industrial d e v e l o p m e n t a r o u n d us. We h a v e a c c e p t e d t h e idea of a p p l y i n g scientific principles b u t now a c h a n g e is coming a b o u t in t h e principles t h e m selves which necessitates a new c o n c e p t of c o n t r o l .