An innovative method to detach droplets at given arc variables is proposed

A novel modification to conventional GMAW is introduced by applying a low-power laser to droplets to generate an auxiliary detaching force. The electromagnetic force needed to detach droplets, thus the current that determines this force, is reduced. The undesired dependence of the metal transfer on the current is decoupled such that the current may be freely chosen to control the weld penetration and weld pool without restrictions as in conventional GMAW due to the need for metal transfer. The resultant process is referred to as laser-enhanced gas metal arc welding. To prove the feasibility of this idea, a constant-power laser was applied to droplets from a 0.8-mm-diameter steel wire in GMAW. A number of experimental conditions that typically would result in short-circuiting transfer in conventional continuous waveform GMAW were designed to conduct laser-enhanced GMAW experiments. It was found that the metal transfer changed from short circuiting to spray in all these experimental conditions as can be seen from high-speed video images. The principles and fundamentals were analyzed to better understand the results and the process.