Precise paint stripping based on photochemical effect by UV laser on honeycomb sandwich panel

As an environmentally friendly new method for coating removal, laser cleaning has been widely used in aircraft skin paint removal recently. However, due to the thermal damage sensitivity of composite materials, current laser cleaning is still mainly used in aluminum alloy skins. In this work, we demonstrate a method for cleaning the surface paint of honeycomb sandwich structures by ultraviolet picosecond laser. The method achieves layer-by-layer and non-destructive removal of paint from composite surfaces. The results show that the top coat is selectively removed when the laser power is 8 W and the scanning speed is 1750 mm/s. When the laser power is 8 W and the scanning speed is 750 mm/s, both top coat and primer are completely removed without any morphological damage for the glass fiber. The temperature monitoring results show that the UV picosecond laser exhibits low-temperature paint removal. The paint removal mechanism of UV picoseconds is dominated by photochemical effects.