No Turning Back: Pipe Welding System Kicks It Up a Notch
Using the PipeworxTM Welding System from Miller Electric, Shinn Mechanical has increased its pipe fabrication quality and productivity with flatter bead profiles, good sidewall tie-in for 30 percent less grinding, and superior weld puddle control – with no wire rejects in over a year.
Posted: June 12, 2012
Pipefitter/welders typically change processes an average of eight times per day. This adds up to a total of 40 minutes to 80 minutes of changeover time. Using a conservative overhead rate of $60 per hour, changeover costs of old welding systems quickly add up to:
• $40 to $80 per day per operator
• $200 to $400 per week
• $10,000 to $20,000 per year
By eliminating unproductive process changeover time to “all of two seconds,” coupled with faster welding speeds, Shinn Mechanical pipefitter/welders can easily achieve their daily goal of 200 weld inches (i.e., completing 20 joints on 10 in diameter pipe).
PROGRAM STORAGE
As noted earlier, this shop works to qualify many procedures for the RMD and Pro-Pulse processes. To facilitate quick changeover between these processes, Sayers uses a dual wire feeder that stores four welding programs on each side. He uses the right side to put in the root pass. “I’ve got my RMD setting, MIG settings for different applications and then I’ve also got a pulsed setting for certain applications,” he says. “I can put a bead into anything with any of those four settings. Then I just switch over to my left side gun, and that’s where my Pro-Pulse side is for my fill and my caps. I can generally, off of those four programs, run anywhere from 2 in Schedule 40 pipe up to as large a pipe as there is” just by adjusting wire feed speed.
To switch between programs, Sayers uses the trigger select function that eliminates the need to return to the feeder’s control panel to switch between passes.
ARCS DESIGNED FOR PIPE WELDING
Unlike other multi-process welding systems, PipeWorx utilizes arc characteristics that are specifically designed for pipe welding. For example, the arc characteristics, metal transfer, wet out and puddle control of Pro-Pulse and RMD produce optimum results in the joints and welding positions typical of pipe welding.
“You can get out of position a little easier and it seems to hold a puddle better,” observes Sayers. “RMD also leaves less wagon tracks in your weld in the side walls of the pipe. When you’re doing high quality work, you don’t have to grind out nearly as much of your base metal to get down to clean metal again [before] your second pass.” Sayers estimates that RMD reduces grinding time by 30 percent compared to conventional short circuit MIG.
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