Investigation on dynamic behavior of laser paint removal based on high-speed shadow imaging technology

Pulse laser is an effective tool for removing paint from aircraft and ship surfaces. The analysis of the laser paint removal process requires a synchronous observation method. In this study, based on high-speed shadow imaging technology, an online examination system for laser paint removal was established. The dynamic behaviors of laser paint removal and substrate damages caused by too high laser pulse energy density were analyzed by examining the removal process of epoxy primer on 2A12 Al alloy surface by laser with different energy densities. The results show that when the laser irradiated the sample surface, some plumes, particles and droplets were formed on the material surface. Further analysis reveals that the generation of plumes was due to the ablation of primer, while the particles were generated under thermal stress. When the laser energy density was too high, the substrate materials melted to form droplets. The plumes generated by laser ablation created an extremely high recoil pressure, under which the particles and droplets were detached from the surface of the material.