Laser cleaning of multilayer paint coatings applied to aluminum alloys

The paper presents a comparison of the effects of laser coating removal with the use of various laser devices. Laser cleaning of the surface layer for the aluminum alloy has been performed. Using different patch trajectory, power densities of the laser beam emitted by the pulsed Nd: YAG laser for the tested material, the best treatment conditions were selected for their cleaning. Basic research included microscopic analysis of surface topography and analysis of chemical composition in micro-areas. In order to clean the surface of contamination, laboratory comparative studies of the removal of coatings were carried out using the surface layer cleaning technique using pulsed laser TruMicro 5325c with UV radiation (343nm). Samples covered with various technological coatings were subjected to several variants of laser treatment (different laser power densities and different numbers of pulses). The paper presents selected results from laboratory tests. A Hirox KH-8700 microscope with digital image analysis was used to observe the cleaned surface layer. The JEOL JSM-7100f device was also used, enabling scanning electron microscopy (SEM) with the possibility of analyzing the chemical composition of the surface layer before and after laser cleaning. The cleaned surface does not have traces of laser melting, and only the effects of cleaning the coating are visible. After cleaning, a highly clean surface was obtained. In the case of very thick coatings, the cleaning process should be repeated several times. In order to intensify the purification process, a laser with a higher average power can also be used.