Abstract
Only a few welding processes for plastics meet the special demands of microtechnology. Laser transmission welding has distinct advantages such as low mechanical and thermal load on the joining parts. Thus the laser is a joining tool which is particularly suitable for the welding of micro plastic parts. There are several process variants, from which contour welding enables the welding of complex and even three-dimensional weld contours. In addition, it is a very flexible process that can be easily adapted to changing part geometries. High-power diode lasers feature certain advantages such as low maintenance and investment and high efficiency, which is why they have been increasingly applied in plastics processing for welding of parts of macroscopic scale. Recent research at the Institute of Plastics Processing at RWTH Aachen University shows that it is also possible to use contour welding with high-power diode lasers to weld filigree and three-dimensional micro structures. Welding experiments with different thermoplastics show, however, that there is a strong influence of some material parameters on the laser welding process, so that some plastics are more suitable than others for the contour welding in microtechnology.