A Phase Field Approach to Model Laser Power Control in Spot Laser Welding

Spot laser welding is largely used in industrial manufacturing, especially in the case of small penetration depth. Unfortunately, welded joins are often polluted by porosities. The formation of porosities depends on complex thermo-hydraulic phenomena. To understand and control these mechanisms, the COMSOL Multiphysics software is used to model both the interaction and cooling stages of an isolated impact made with a Nd:YAG pulsed laser. The model is based on the Phase Field method in order to apprehend the evolution of the liquid-gas interface shape. The numerical results are compared to experimental characterizations for different operating conditions. At last, the benefic effect of the laser power control (pulse shaping) is demonstrated.