Numerical Simulations and Analysis of Mechanisms of Paint Removal with a Pulsed Laser

To study the process of removing acrylic polyurethane paint from a 2024 aluminum alloy surface with a pulsed laser, we establish a finite-element model via COMSOL Multiphysics software. We analyze and verify experimentally effects of different parameters on the temperature and stress fields during laser exposure and discuss the mechanism of laser paint removal. At slow scanning speeds, the heat accumulation is greater, with a higher instantaneous maximum temperature and thermal stress on the paint surface. The temperature and stress increase with laser energy density. The paint is completely removed at an energy density of 9.44 J/cm2. During paint removal, energy is transferred to the metal substrate via heat conduction. The laser also directly interacts with the metal and ablation is visible on the substrate surface. Analysis of the surface morphology indicates that the mechanisms of paint removal are mainly ablation, as well as vibrational and impact effects. These results provide a reference for the selection of process parameters for paint removal with lasers, as a well as an in-depth analysis of the mechanisms.