In the case of welding with CO2-laser the overall efficiency will be between 2% and 5%. Using a Nd:YAG-laser the efficiency is only between 1% and 2%. Compared to that, metal arc welding has a very high efficiency and the arc welding machine has a more than 10 times lower price than a laser system. Besides several distinctions concerning process and welding results laser beam and arc metal welding are characterized by different geometries of the melt pool. In the case of arc metal welding the weld seam is defined by a lower ratio of seam depths to widths. In laser welding this ratio is quite high. These distinctions are influencing e. g. geometrical tolerance requirements, gaps bridging ability or the heat input which is necessary to solve the defined welding problem.
Both welding processes are governed by plasma phenomena. The paper describes the plasma phenomena and how it is possible to combine both processes to reach a higher efficiency. By combing arc and laser beam welding in an optimal way, on the one hand the welding speed could be increased and on the other hand the same welding depths could be reached with a reduced laser power.
In overlap welding as well as in case of gaps the combination allows to get a bigger seam width and that means a bigger gap between the workpieces could be excepted. Welding results on steel sheets in overlap and butt joints are discussed with regard to process parameter for CO2- and Nd:YAG-laser welding combined with the arc metal welding process.