Hi.
I work as a welding/machine tool engineer & have made a tig seam welding plc controller for airbus which works fine, now. I had to deal with hf problems so I reverse engineered Hitachi suppression units, as the arduino only seemed to crash when plugged into the welding set or positioner. I then went on to cross wire a small inductor transformer so that it cancelled out the interference waveform in its coil. This even works directly connected to the torch so I can measure voltage.. It was a complete pain but I hope that helps as I was ripping hair out myself.. I am having problems with building a cold wire feeder programming wise as using millis is driving me mad but can't use delay due to the reaction time when adjusting the retract & speed etc.. If you have Any pointers would be great, also any problems you have with suppression etc I can help no peoblem.
Paul.