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讨论了热应力在短脉冲激光清洗油漆过程中的作用,从一维热传导方程出发,计算了由热膨胀产生的热应力以及根据粘附力公式计算出了油漆的粘附力.通过比较热应力与粘附力大小,得到激光清洗油漆的条件,进而建立一维短脉冲激光除漆模型.根据此模型可计算出:波长为1064 nm,脉宽为10 ns的激光清除铁基底上厚度为40μm橙色漆的清洗阈值为0.5 J/cm2;不同能量密度下使得油漆脱落所需的激光作用时间;激光脉冲作用过程中铁基底的温度变化情况.实验所测得的清洗阈值为0.57 J/cm2,与理论结果接近.实验与理论都表明当能量密度过高时,铁基底的温度升高很大,超过其熔点,铁基底被损坏.并考虑了激光清洗铝基底上油漆的情况.
The effect of thermal stress on the process of short-pulse laser cleaning paint was discussed. Based on the one-dimensional heat conduction equation, the thermal stress caused by thermal expansion was calculated and the paint adhesion was calculated according to the formula of adhesion. The size of the adhesion, laser cleaning paint conditions, and then establish a one-dimensional short-pulse laser paint removal model.According to this model can be calculated: the wavelength of 1064 nm, pulse width of 10 ns laser removal iron substrate thickness of 40μm orange Lacquer cleaning threshold is 0.5 J / cm2; laser energy required to make the paint off at different energy densities; temperature change of the iron substrate during the laser pulsing process. The cleaning threshold measured in the experiment is 0.57 J / cm2, The results are close.Experiments and theories have shown that when the energy density is too high, the temperature of the iron substrate rises greatly beyond its melting point, the iron substrate is damaged, and the case of laser cleaning the aluminum substrate is considered.