THE L3 SYSTEM — QUALITY CONTROL IN MANUFACTURE 1005 



2. Useful techniques for improving manufacturing processes and for 

 indicating the need of replacement or repair of worn tools and machines 

 in the factory. 



3. A device for promptly focusing attention on deviations due to 

 changes in raw material or components. 



All of these items are useful to both the design and manufacturing 

 engineer in evaluating the relationship between the product design and 

 the manufacturing and testing facilities. 



The relatively small number of L3 amplifiers produced to date and the 

 introduction of product design changes and modifications in manufactur- 

 ing methods, which are inevitable during the early production period of 

 a complex product of this nature, make it impossible to form final con- 

 clusions relative to the correlation between the distributions of related 

 characteristics of the components and the final amplifier. Experience 

 indicates, however, that these methods are of considerable assistance to 

 the factory during the introduction of new designs of products of this 

 nature and should, in addition, become a permanent and useful part of 

 the production of products having such critical requirements. 



5.0 References 



1 . H . F . Dodge , B . J . Kinsburg and M . K . Kruger , The L3 Coaxial System — Qual- 



ity Control Requirements, see pp. 943 to 968 of this issue. 



2. W. A. Shewhart, Economic Control of Quality of Manufactured Product, D. 



Van Nostrand Co., Inc., New York, N. Y. (1931). 



3. ASA War Standards Zl.l — 1941, Guide for Quality Control; Z1.2— 1941, 



Control Chart Method for Analyzing Data; and Z1.3 — 1942, Control Chart 

 Method for Controlling Quality During Production. American Standards 

 Association, New York, N. Y. 



4. H. T. Wilhelm, Impedance Bridges for the Megacycle Range, Bell Sys. Tech. Jr. 



31, pp. 999 to 1012, Sept., 1952. 



5. G. T. Ford and E. J. Walsh, The Development of Electron Tubes for a New 



Coaxial Transmission System, Bell Sys. Tech. J., 30, 1103 to 1128, Oct., 1951. 



6. E. J. Walsh, Fine-Wire type Vacuum Tube Grid, Bell Lab. Record, 28, pp. 



165-167, April, 1950. 



7. Dorian Shainin, Quality Control Methods — Their Use in Design — Part III, 



Machine Design, Sept., 1952. 



