May 5, 2014
Q: I am having trouble making welds that are all the same length when using GMAW. How can I create tie-ins that are all in line with each other and spaced out as they should be?
A: It is understood throughout the industry that most weld defects are attributed to weld stops and starts. We automate (or change from manual to semiautomatic) to improve cycle time and quality. Most of that quality improvement comes from eliminating starts and stops. Welding starts can lead to overlap, incomplete fusion, and slag inclusion, while stops typically lead to cracks and undercut.
Some of these discontinuities may be considered acceptable, but stacking them on top of one another in a multipass weld is just flirting with disaster.
Stops and starts are a necessary evil in welding. We can minimize their negative effects, however, through techniques during manual welding and through weld data settings for semiautomatic and automated welding.
In GMAW those weld settings that can be added to many wire feeders include:
As for your welding technique:
You could probably search the Internet for an article on weld stops and starts and get plenty of horror stories. In that same search you will find oodles of “pixie dust” salesmen with quick-fix products or equipment that claim to take all those troubles away.
Stick with common sense. Equip your feeders with the settings that help improve weld starts and stops, and be sure to use good welding techniques.
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