FLEXIBLE REPEATER MANUFACTURE 125 



central conductor to form the seal. After the specified temperature-time 

 cycle, the retort was removed from the furnace, allowed to partially 

 cool and then placed into an annealing oven. 



Vertical furnaces and retorts were used for brazing, decarburizing, 

 oxidizing and glassing. By varying the type of gases flowing into the 

 retorts, atmospheres which are reducing, oxidizing, or neutral were ob- 

 tained. To provide maximum uniformity of process, separate retorts 

 and holding fixtures were provided for operations involving hydrogen 

 and for air-nitrogen operations, so that a retort or a fixture used for 

 hydrogen treatments was never used for oxidizing or glassing. 



PILOT AND REGULAR PRODUCTION 



We called our first efforts Practice Parts and Training; the next we 

 called Pilot Production. Next, certain items identified as Trial Laying 

 Repeaters and Oscillators were manufactured for use in "proving in" 

 the ship laying gear. To prove in manufacturing facilities, a few un- 

 equipped housings were made without the usual electrical components 

 normally in a repeater. Similarly, each of the apparatus components 

 and parts required exploratory and pilot effort before regular production 

 could be undertaken. 



As might be expected, the manufacturing yield of components meeting 

 all requirements was very low during the early stages of the undertaking. 

 However, substantial improvement was brought about as experience 

 was gained. Comments on some of the production problems, highlights, 

 and yield results, follow. 



Paper Capacitors were manufactured only after painstaking qualifying 

 trials and tests had been performed on each individual roll of paper. 

 Cycling and life testing, procurement of acceptable ceramic parts and 

 gold-plated tape and cans, selection and matching of rolls of paper for 

 winding characteristics, and similar problems, all had to be completely 

 resolved to a point of refinement previously unattempted for telephone 

 apparatus. 



Composite percentage yield for all operations on paper capacitors is 

 shown in Fig. 5. Yield is shown as the ratio of finished units of acceptable 

 quality to the number of units started in manufacture. 



Mica Capacitors were made from only the most meticulously selected 

 laminations, as mentioned earlier. Even the best mica is particularly 

 susceptible to damage in processing. In spite of experience and knowl- 

 edge of this, the multiple handling of the laminations contributed an 

 unusually high material shrinkage as each separate lamination needed 

 to be cleaned, then handled individually many times through the proc- 



