采用COMSOL Multiphysics建立了纳秒脉冲激光清洗2024铝合金表面丙烯酸聚氨酯漆层的有限元模型,分析了不同参数对激光清洗温度场和清洗深度的影响,并进行了实验验证。结果表明:扫描速度以搭接率的形式影响清洗效率,扫描速度越慢,清洗速率越小,当搭接率为50%时具有合适的清洗效率;随着激光能量密度增加,漆层表面和基体表面的最高温度线性升高,当激光能量密度达到25 J/cm 2时,激光辐照区域的漆层材料完全被去除,铝合金基体的烧蚀深度为50 μm;在激光能量密度为25 J/cm 2,搭接率为50%的实验参数下,基体表面沟槽峰谷高度为50.234 μm,在此参数组合下可以获得良好的符合涂装工艺要求的表面。该结果可为研究纳秒脉冲激光清洗及其工艺参数的选择提供参考。

The finite element model for an acrylic polyurethane paint layer cleaned by a nanosecond pulsed laser on a 2024 aluminum alloy surface was established using COMSOL Multiphysics. The effects of different parameters on the laser cleaning temperature field and cleaning depth were analyzed, and the findings were verified by an experimental study. The results show that the scanning speed affects the cleaning efficiency in the form of an overlapping rate, where a low scanning speed corresponds to a reduced cleaning rate. A suitable cleaning efficiency is achieved with an overlapping rate of 50%. As the laser energy density increases, the maximum surface temperatures of the paint layer and the substrate increase linearly. When the laser energy density reaches 25 J/cm ², the paint material in the laser irradiation region is completely removed and the ablation depth of the aluminum alloy substrate is 50 μm. For a laser energy density of 25 J/cm ² and an overlapping ratio of 50%, the peak-to-valley height of the substrate surface groove is 50.234 μm. Thus, a suitable surface that meets the coating process requirements can be obtained with these parameters. These results provide a reference for studying nanosecond pulse laser cleaning and for selecting appropriate process parameters.