Process and mechanism of paint stripping on CFRP by UV nanosecond laser

Laser cleaning shows exciting promise for removing paint from aircraft skins. This paper focuses on the application of a 355 nm (UV) nanosecond pulsed laser for paint removal from aircraft skin composites. First, the effects of process parameters on laser paint removal are analyzed, and mapping relationships between these parameters and the depth and roughness of paint removal are established. After that, the micromorphology and dynamic behavior of the samples are observed and characterized with the help of SEM, EDS and high-speed photography. Finally, the paint cleaning mechanism and damage mechanism of the 355 nm laser are discussed. The results show that the removal of paint is a combined result of photothermal and photochemical effects, while the damage of carbon fiber is caused by thermo-mechanical forces. When the laser repetition frequency is 50 kHz, the scanning speed is 1100 mm/s, and three cleanings are performed, the paint on the CFRP surface can be completely removed while maintaining the integrity of the carbon fiber.