: Imhoff, R.; Behler, K.; Beyer, E.; Maischner, D.

Abstract
This paper demonstrates that different possibilities for an overlap welding of zinc coated materials by lasers are developed in principle. In case of layer thicknesses above 5 Mym in the joining area weld seams which are nearly without pores can be achieved by adapted processing parameters as high line energy and a focus position at the bottom edge of the sheet. The use of additional assist gas flows or the engraving of knurlings enable to weld thick coated sheets. By means of a process monitoring from the processing side it is possible to detect the degree of full penetration and thus to control one aspect of the welding process and to ensure a constant seam quality concerning root detection and porosity.