E-Mail. Ed great site, l loved your thoughts on the Panasonic HM series welders. First I was wondering is it necessary to pulse weld aluminum. Also are you familiar with the Panasonic RA series welder with digital low pulse out put? If so, I was wondering if it is necessary to always use the low pulse feature? I have a Panasonic unit with the low pulse mode, it's a lot of trouble setting the required "optimum" low pulse weld parameters. Possibly the problem is we are running our robots too fast. The bottom line with the low pulse settings, we never got close to a manual "TIG look a like welds" that the Panasonic rep said we could attain.

Another point, in regards to the Panasonic HM power source, is it the industry standard to have accruing problems with pulsed equipment? We have 4 robots using Panasonic HM power sources, and to keep up with the weld power source issues and failures we have to keep 6 HM's to keep the four robots running. I believe this costly requirement is absurd, but I keep hearing I am wrong. Any info you send my way on this subject would be greatly appreciated!!! Thanks G Baird

Ed's reply. Reference product reliability. It's been my experience that the more electronically sophisticated the pulsed MIG power source the less reliable its likely to be, there are of course exceptions however they are few. The fact that the pulsed power source manufactures have to come out with a new or revised model every six to twelve months is an indication that what they sell does not provide optimum welding results or its simply not reliable.

Today's pulsed equipment which the average electrician will find impossible to repair has established a new equipment requirement for the welding industry. If you want to keep a robot cell running for three shifts, five days a
week, " its wise to ensure you have a spare pulsed power source at your facility"

• There is an important relationship between optimum weld transfer, pulse frequency, and the required pulsed wire feed rates.
  
  I believe the "low pulsed mode" on the HM equipment may be an attempt to duplicate the cosmetic aluminum fast freeze weld patterns that are typically found on manual TIG bike frame welds.
  
  With a manual TIG, pulsed alum weld you may end up with 3 to 10 pulses per second with a manual fed wire feed rate of less than one pound per hour, (low GMAW pulsed rates require low wire feed rates, plus low peak current). In contrast and from a robot perspective, unnecessary use of the the low pulsed mode of weld transfer would be ridiculous.
  
  Why utilize any weld transfer mode that requires that the robot go slower?
  Why use any weld mode that provides less weld fusion potential for the weld?.
  Why use a low pulse, fast freeze weld mode that increases weld porosity potential?. Why travel slow and increase the weld distortion potential?
  
  A good method to control weld distortion on thin gage, robot applications is to turn up the wire feed rate and increase the robot weld travel rate. The bottom line, to justify that expensive pulsed MIG power source that is not as reliable, as traditional, lower cost CV equipment, I hope you are welding aluminum applications in the range of 0.04 to 0.100. Applications thicker than this are readily welded with traditional spray transfer with a CV power source that will costs 60% less than a pulsed machine. Also with the CV power source you should at last achieve at least 10 years trouble free use and after ten years any electrician can provide the necessary equipment repairs. Extensive pulsed equipment data available in the weld equipment and pulsed weld sections of this web site. Send your pulsed equipment issues to ecraig@weldreality.com