3D FINITE ELEMENT MODELLING OF CONTOUR LASER TRANSMISSION WELDING OF POLYCARBONATE

A three-dimensional finite element model was developed for the simulation of heat transfer in contour laser transmission welding of amorphous polymer - polycarbonate. By introducing mass flow in the model, a time-dependent, contour welding process was solved as a time-independent heat transfer problem (Quasi-static model). The short solution convergence times (under three minutes for a set of process and material conditions) and model output agreement with the experimental data indicate that the Quasi-static approach is convenient for use in solving heat transfer problems in laser contour welding. Combined with experimental data, the simulation results indicate that, in contour welding of PC, welding initiates when temperature at the weld interface reaches the maximum of 200 T. The simulation results also provide further insight into the effect of proportionally increasing laser scan speed and power (i.e., while maintaining constant line energy).