Lehrstuhl für Fertigungstechnologie, Universität Erlangen-Nürnberg

Laser transmission welding of transparent polymer parts



Datum: 12.02.2009


Author


Reporter

  • Prof. i.R. Dr.-Ing. Dr.-Ing. E.h. mult. Dr. h.c. mult. M. Geiger
  • Prof. em. Dr.-Ing. Dr. h.c. Gottfried Wilhelm Ehrenstein

Focus of this work was researching the basics for laser transmission welding of two transparent plastic parts. The central idea of the investigations is realizing temporally and locally defined energy deposition inside the parts to heat and weld them at the without use of additional absorbers. In order to calculate the temperature field and deformations caused by the laser irradiation a three dimensional thermomechanical simulation model of the process was implemented. This model was used to layout apt focussing optics for welding the transparent parts. The investigations carried out with these optics were analysed by specially adapted thermography which enables depth resolution of the thermal fields. With this access to heat distribution inside the materials direct correlation between the simulation calculations and the experiments was possible. This combined approach led to the finding that the intrinsic absorption of polymer materials suffices to weld them with the right joice of the laser system and focussing optics.