UV-Laser Treatment of Thermoplastic CFRP Parts for Paint Applications

The surface pre-treatment of a high performance thermoplastic CFRP for improved paint adhesion was investigated with a 30 W KrF UV-excimer laser (248 nm). Surface analysis showed no fiber release or visible removal of the thermoplastic matrix but an effective removal of silicon organic release agent residues. The ablation on nanoscale led to a cleaning effect, which improved the paint adhesion. Paint adhesion tests with a solvent-reduced paint system showed good results even after long-term ageing in water or under warm and humid conditions. After UV-laser treatment the adhesion of industrial polysulfide sealants could be achieved even without adhesion promoter. Large scale application concepts based on a compact UV-excimer laser system showed high potential for robotic guided applications with high treatment rates. Keywords: UV-excimer laser, thermoplastic CFRP, release agent removal, pre-treatment, solvent-reduced paints