Page 34 - MetalForming-May-2018-issue

Welding Well
Delving deeper, the application engineers noted that, beyond personal preferences, too many operators don’t know why they should push or drag the gun in a given solid-wire applica- tion, nor do they ask why gun angle is so critical. For the record:
• Pushing directs arc force away from the puddle to produce a wider and flatter bead with less penetration.
• Dragging directs arc force at the
With a shortage of skilled welders, compa- nies benefit from advanced GMAW sys- tems with preset pro- grams for welding with various processes, syn- ergic controls and smart GMAW functions.
puddle to produce deeper penetration and a narrower bead with more buildup.
• Achieving a gun angle (or angle of travel) of 5 to 15 deg. from perpendi- cular is required in most situations.
• Seeking recommendations for spe- cific applications from filler-metal manufacturers is better than seeking advice from online bulletin boards that may contain inaccuracies.
“The problem is that people practice with poor mechanics, and practicing wrong isn’t going to make you a better welder,” said Lott. “They use too much gun angle and don’t realize it increases arc instability and spatter, much less realize they’re losing penetration.”
Wanted: More Questions
In summary, operators who know the whys of GMAW have a host of con- trols besides wire-feed speed and volt- age. Unfortunately, the industry has a shortage of such operators, and welding businesses need to deliver results today. Enter preset programs and functions that automatically adjust and compen- sate for some GMAW variables. These are good things, right? Yes, but...
“Not enough people know why fac- tors such as electrical stickout and con- tact-tip-to-work distance influence arc stability, wire melt-off rate, penetration and weld-bead shape,” said Ginder. “Yes, preset programs, synergic controls and smart GMAW functions help com- pensate, enabling operators with less skill to obtain good results. But we’d be happier if more people asked: ‘Why do they help?’” MF
Author’s note: The article, Optimize Aluminum Welding Performance, in the May 2015 issue of MetalForming, discusses pulsed GMAW controls in detail and is worth reviewing: metal- formingmagazine.com/magazine/arti- cle/?/2015/5/1/Optimize_Aluminum- Welding_Performance.

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MetalForming/May 2018
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