Laser cleaning is a non-contact and straight forward method to remove the paint from the substrate, based on the mechanism of thermal stress. In order to understand the mechanism detailly, it is crucial to investigate the relationship between the laser fluence, interaction time and the temperature rise quantitatively. Herein, we exhibit thermal stress is the primarily mechanism in the paint removal process by nanosecond (ns) laser pulses. Based on this, a theoretical model of nanosecond laser peeling off the paint is developed successfully. It is worth mentioning that the formation of plasma, plasma shielding effect and temperature dependent absorptivity are critical factors, which is considered in this model. The model can predict the theoretical cleaning and damage thresholds based on the mechanism of thermal stress. According to the temperature distribution in this model, it could be found the optimized parameter is at the laser fluence of 1.56 J/cm². Together, it is expected that this study could provide a theoretical reference regarding to nanosecond laser cleaning the paint layers and pave the way for reducing the substrate damage in various industrial applications.

激光清洗是一种基于热应力机理的非接触式直接方法，可从基材上去除涂料。为了详细了解该机理，至关重要的是定量研究激光通量，相互作用时间和温度升高之间的关系。本文中，我们表现出的热应力是纳秒（ns）激光脉冲在涂料去除过程中的主要机理。在此基础上，成功建立了纳秒激光剥离涂料的理论模型。值得一提的是，等离子体的形成，等离子体的屏蔽作用和与温度有关的吸收率是关键因素，在此模型中已将其考虑在内。该模型可以根据热应力机理预测理论上的清洁和损坏阈值。²。总之，可以预期的是，这项研究可以为纳秒激光清洗涂料层提供理论参考，并为减少各种工业应用中的基材损坏铺平道路。