The APL Resistance Welder

In order to improve the reliability of welds used in satellite construction, a new welding machine has been developed. This welding machine consists of a set of storage batteries to supply current, a bank of transistor switches to regulate the magnitude and duration of the current, and a commercial welding head. The new welder produces the following pulse characteristics: 1) a pulse whose current and duration can be independently controlled to a high degree of accuracy, 2) a pulse whose current remains very close to its predetermined value regardless of changes in resistance in the weld being made, 3) a pulse which is constant for identical settings from day-to-day and from machine-to-machine.