ELECTROFORMED CONDUCTOR FOR TELEPHONE DROP WIRE 1101 



crease in current density meant a rate of deposition double that which 

 had been predicted. 



On this pilot machine the operating limits of the various plating and 

 cleaning solutions were established. Methods of control, materials of 

 construction and design features were evaluated. A field trial lot of 

 200,000 linear feet of drop wire and numerous samples of wire were 

 processed for examination and design approval. 



Some time was spent in making the basic plant decisions, evaluating 

 pilot plant experience and carrying through the numerous special investi- 

 gations required to guide the engineering design. The detailed engineer- 

 ing and drafting were begun and firm orders placed for equipment. 



DESIGN PREMISES 



Certain design premises became apparent from experience with the 

 pilot plant. The nature of the process dictated continuous operation on 

 a three-shift, seven-day basis. To secure such operation, it was necessary 

 to duplicate certain critical facilities, use the largest practical reel size 

 for maximum wire run time and to employ great care in the design of the 

 wire handling equipment to minimize wire breaks. The second premise 

 was low maintenance. This required that the materials in contact with 

 the various chemicals could be selected only on the basis of extensive 

 corrosion tests. This involved the study of many of the grades of stainless 

 steel as well as the rarer metals and the broad field of plastics and elasto- 

 mers to select suitable materials for tank lining, machine parts, and 

 piping. 



Substantially automatic operation was set up as another design objec- 

 tive. This, of course, involved the isolation of the factors requiring con- 

 trol and selection of the most suitable means. The safeguarding from 

 waste of valuable solutions was a fourth consideration. Spare tank capa- 

 city was provided in case any of the storage tanks developed leaks and 

 had to be repaired. Facilities were required to recover electrolyte carried 

 out from plating operations by the wires themselves. Means had to be 

 provided for recharging and reconditioning the various electrolytes. Still 

 another premise was the permanency of solution: no dumping and re- 

 placing of plating solution was contemplated. And, of course, safety to 

 personnel was a must. In addition to the usual hazards from acids and 

 alkalis in a chemical plant, accidental mixture of electrolytes could give 

 rise to highly poisonous gases. This necessitated the selection of highly 

 reliable piping materials and the provision of adequate employee pro- 

 tective devices and routines. 



