Finite Element Method (FEM) Based Simulation of Continuous Laser Ablation: Surface Temperature and Depth Profile Evolution

Abstract

Laser ablation has been widely used for material removal on different types of substrates. Accurate feature profile fabrication with minimum damage to the surrounding material requires precise control of the laser and material parameters. One approach to achieve this is by establishing a simulation model to help process control and optimization. However, laser ablation is a complex process that is difficult to model. In this paper, numerical simulation models have been established to identify the temperature at the ablation surface and the ablation depth profile evolution over time. The ablation has been modeled using the heat transfer in solids module in COMSOL Multiphysics with the manual material definition of high-density polyethylene (HDPE). The laser beam is modeled as a continuous heat source by utilizing a ramp function. Information for establishing a pulsed laser system has been provided. Results are provided for the surface temperature and depth profile evolution for various time steps. Results of the simulation of laser ablation of HDPE sample using a 50W laser using both the models were presented. The next step of our work is to validate the simulation results by comparing it against experimental data. This will render these models to have the potential to be able to predict the ablation crater profile with higher accuracy. This model will pave the way for a better understanding of the ablation threshold conditions and identifying the ablation initiation in any material, given the material properties are known.