Development and experimental analysis of laser-assisted plasma ARC welding

A new welding heat source consisting of a plasma arc and a coaxially superimposed low-power laser beam was developed. For this purpose, a single-mode fiber laser beam was guided through the hollow tungsten electrode of a commercial plasma welding torch. The capabilities of the corresponding welding process were experimentally analyzed for bead-on-plate welding trials on steels and aluminum alloys. Besides the evaluation of the resultant seam geometries also the behavior of the arc under the action of the additional laser beam was studied by means of arc voltage measurements and high-speed camera observations. The results of this study demonstrate so far beneficial improvements of the combined process in comparison to the single welding techniques. First, the melting efficiency can be significantly increased for particular parameter constellations. Secondly, the additional laser beam is very capable of stabilizing the arc attachment under conditions of low arc currents and/or high welding speeds. The experimental results also provided some new insights into possible physical reasons of the observed laser-arc interactions.A new welding heat source consisting of a plasma arc and a coaxially superimposed low-power laser beam was developed. For this purpose, a single-mode fiber laser beam was guided through the hollow tungsten electrode of a commercial plasma welding torch. The capabilities of the corresponding welding process were experimentally analyzed for bead-on-plate welding trials on steels and aluminum alloys. Besides the evaluation of the resultant seam geometries also the behavior of the arc under the action of the additional laser beam was studied by means of arc voltage measurements and high-speed camera observations. The results of this study demonstrate so far beneficial improvements of the combined process in comparison to the single welding techniques. First, the melting efficiency can be significantly increased for particular parameter constellations. Secondly, the additional laser beam is very capable of stabilizing the arc attachment under conditions of low arc currents and/or high welding speeds. The exper...