Going to work
Implementing multiple-gun processes, fabricators can retrofit two or more
guns to an existing rocker-arm or press-welding machine or purchase a
new machine designed to accept several weld guns. Retrofitting is costly:
to keep distance from transformer to electrodes short, it may entail removal
of the entire front of the machine, leaving only the transformer intact. The
machine manufacturer then redesigns the machine to hold the guns close
to the transformer for series or indirect welding. Purchase of a machine
designed for multi-gun welding may allow the user to add more guns easily
and economically.
Multiple-gun welding machines come with one or more transformers, some
with dual secondary output. Each transformer powers two or four weld
guns. The transformers can fire the weld guns simultaneously if enough
power is available, or in cascading sequence to smooth out power demand.
Cascading also gives good weld-quality control, since operators can set
time and current individually for each weld sequence.