Numerical Simulation of Ultra-Short Pulse Laser Ablation Based on Comsol

In ultra-short pulse laser machining and micro/surface processing, accurate simulation of laser ablation is important for understanding laser-target interaction and improving ablation performance, but remains challenging. In the present work, a modified two-temperature model (TTM) incorporated with instant material removal procedure is proposed. A two-dimensional axisymmetric TTM is established using COMSOL Multiphysics software, and material removal process is described using the deformation geometry module. Using TTM, the non-equilibrium characteristics of ultra-short pulse laser ablation is captured. Based on energy conservation, the gird deforms at a velocity related to the ablation rate of the target material, giving a reasonable prediction of instant target surface profile. Using this modified method, we simulate several cases of ultrashort pulse laser ablation of Ti6Al4V and stainless steel. Simulation results verify that taking into account properly the instant material removal improves numerical prediction of ablation depth significantly. It is also demonstrated that this method is applicable to different materials and under both single- and multi-pulse ablation scenarios.