Welding Journal - May 2012

Laser-enhanced gas metal arc welding (GMAW) is an innovative process recently proposed and developed at the University of Kentucky (Refs. 1–3), shown in Fig. 1. It adds a relatively low-power laser to conventional GMAW, and the objective is to provide an auxiliary force to help detach the droplet at a desired diameter with a desired welding current. In laserenhanced GMAW, the droplet size is a critical parameter that determines the process stability and produces a desired appearance and quality of welds. Relatively large droplet sizes will lead to ripples in the welds and decrease the directionality of the welds. In laser-enhanced GMAW, laser recoil pressure force is the additional detaching force compared to conventional GMAW. However, it is hard to directly calculating this force value precisely as many physical coefficients are unknown. For the recoil pressure acting on a substrate during intense laser evaporation, Ref. 4 gave the following:1/2