激光入射角度对去除2024铝合金表面油漆的影响

Effect of Laser Incident Angle on Paint Removal of 2024 Aluminum Alloy Surface

研究了激光不同入射角度对油漆去除深度、表面形貌与粗糙度的影响。通过改变激光束与样品的夹角完成不同角度的激光除漆试验,以2024铝合金为研究对象,检测分析表面油漆去除效果。相同条件下,油漆去除深度随激光入射角度的减小呈先增加后减小的趋势,当激光入射角为70°时,达到最大油漆去除深度。在激光能量密度为5 J/cm^(2)时,激光入射角70°相比于40°情况下,油漆去除深度增加160.57μm,这种差值会随着油漆厚度的增加而更加显著。同时,激光入射角度会改变样品的表面粗糙度,当激光入射角为70°时,获得最小的表面粗糙度,仅比初始表面粗糙度增大0.438~0.812μm。改变激光入射角可以降低烟羽在激光传输方向的长度与烟羽粒子浓度,减小激光能量损失。当激光能量密度为0.5~2 J/cm^(2)时,除漆机理主要是烧蚀效应,当激光能量密度大于2 J/cm^(2)时,则是烧蚀效应与热膨胀效应共同发挥作用。

In this paper,the effects of different incident angles of laser on paint removal depth,surface morphology,and roughness are studied.By changing the angle between the laser beam and the sample,the laser paint removal test at different angles is completed,and the 2024 aluminum alloy is used as the research object to detect and analyze the surface paint removal effect.Under the same conditions,the paint removal depth increases first and then decreases with the decrease of the laser incident angle.When the laser incident angle is 70°,the maximum paint removal depth is reached.When the laser energy density is 5 J/cm^(2),the paint removal depth at the inflection point increases by 160.57μm compared to 40°,and this difference increases as the paint thickness increases.In addition,the incident angle of the laser will alter the surface roughness of the sample.Similarly,the minimum surface roughness is obtained at 70°,which is increased by 0.438‒0.812μm when compared to the initial surface roughness.The laser incident angle can also reduce the length of the smoke plume in the laser transmission direction and the concentration of plume particles.When the laser energy density is 0.5‒2 J/cm^(2),the paint removal mechanism is the main ablation effect,but when it exceeds 2 J/cm^(2),it becomes a combined effect of ablation and thermal expansion.