I've been doing research into pulsing and PWM for various reasons. And I'm split. Most commercial literature seems to tout the advantages of DC pulsing in that it "stiffens" and narrows the arc, which increases power density giving more penetration. This lets you increase travel speed or control penetration.
However I'm sitting on several papers, plus my own research that shows pulse welding does not increase penetration, regardless of frequency from 0HZ to 5Khz. I've tended to see some benefit from increased ratio of background to peak current, but there's a practical limit and the benefit is not substantial. Some further research digs up that in tube mills welding was considered a speed limitation. Companies such as Liburdi developed "True Square wave" power sources. Ones that output current extremely close to an actual square wave.
http://www.liburdi.com/LiburdiAutomation/Pages/LT1000-HS.pdfApparently without a "true square wave" the arc would never constrict. Now I'm having a hard time cutting through what is marketing hype and what's reality. I'm also having a hard time figuring out how the output would compare from a "true square wave" system like Liburdi and a conventional inverter based industrial or robotic power supply from miller or lincoln. I'm guessing I'm going to have to find an electrical tech, and hook up an oscilliscope.
Any thoughts or experience?