Re: CNC Welding

I don't know how, or if it fits, but we have a person using TIG
welding with our low cost Torch Height Controller (THC) to sense the
gap voltage and adjust the head height. The THC300 sold by
www.campbelldesigns.com is based on that design. It needs to run
with MACH2 as a software controller. The MIG process may be somewhat
different. The THC uses the "Constant Current" aspect of plasma and
TIG, meaning that the welding/cutting unit tries to maintain a
constant current by adjusting it's voltage at the tip. The voltage
is directly porportional to the distance of the arc gap so can be
captured and used as a feedback to adjust the height (like terrian
following radar). We worked with Art, the author of MACH2, to
include the Z control and torch logic so the THC does not require
it's own processor and complicated sensing probes to work.

Another aspect is the head movement along the weld using MIG. By
hand, when welding with a stick or wirefeed welder, you need to move
the "pool" from side to side as you travel up the path (actually in
a "J" or "U" type stroke). If you need to duplicate that technique
in CNC you will need to have a CAM program that will put those moves
in or spend a lot of time drawing loops in your CAD file! I would
approach Les at SheetCAM (www.sheetcam.com) and see if he would
consider adding a welding "pattern" to his product. He has already
helped out a plasma shopt that want to cut holes in pipe and needed
the head to automatically adjust the Z as it cut the slope.

Tom C