CABLE DESIGN AND MANUFACTURE 197 



4 Panning and testing of core 



5 Jointing of core 



6 Application of return tapes, teredo tape, fabric tape, jute bedding and 



binding string 



7 Application of armor wire and outer jute layers 



8 Storage in tanks, testing 



9 Splicing in repeaters, testing 



The only important difference in the sequence of the manufacturing 

 operations at the two plants was the use of separate operations for steps 

 6 and 7 at Submarine Cables and the combination of these operations 

 in one machine at Simplex. 



Other minor differences in process methods related to raw materials. 

 For example, the American supplier purchased polyethylene already 

 compounded with butyl rubber and antioxidant in granule form, ready 

 for use. The British supplier purchased polyethylene, butyl rubber and 

 antioxidant separately, and performed the compounding in the cable 

 factory. 



STRANDING OF CENTRAL CONDUCTOR 



The central conductor was stranded on a machine which included a 

 revolving carriage with suitable arbors for the three surround tapes. It 

 was equipped with brakes designed to assure equal pay-off tension among 

 the tapes and with detectors to automatically stop the strander in case 

 of a tape break. Each tape was guided through contoured forming rolls 

 to shape the tape to the center wire. 



The joints between successive reels of wire and tape used in fabrication 

 of the central conductor were butt brazed. The brazes w^ere staggered to 

 avoid more than one braze in a given cross-section of the conductor. The 

 quality of the brazes in these components was controlled by a qualifica- 

 tion technique described below in the section on core jointing. 



The strand was drawn through several forming dies to size the finished 

 diameter of the central conductor accurately. No lubrication was used 

 because the removal of the resultant residues, which could contaminate 

 the polyethylene insulation, was difficult. The taper in the central con- 

 ductor diameter due to the die wear w^as controlled by appropriate re- 

 placement of tungsten carbide dies, where used, or by the use of a 

 diamond die where the rate of die wear is less than 1 or 2 micro-inches 

 per mile. 



The stranding area in both plants was enclosed and pressurized to 

 guard against dirt and dust settling on the central conductor. A high 

 standard of cleanliness was maintained for parts of the machine which 

 touched the conductor or its components. Undue wear of the guide faces 



