Laser welding. The laser welding of plastics is developing increasingly into a genuine alternative to conventional technologies. In particular, perfect surface quality, flexible guiding of the weld and minimal introduction of thermal and mechanical energy are combining to open up more and more new design possibilities. An important aspect is the laser-friendly design of the parts being welded. This includes good optical scattering and absorption properties of the plastics, as well as suitable gap specifications and appropriate geometries for optimum application of the contact pressure.