Investigation on heat transfer and ablation mechanism of CFRP by different laser scanning directions

Abstract

Carbon fiber reinforced plastic (CFRP) is widely applied to aviation, medical, and motorbike industry fields, thanks to its excellent performances of mechanical properties and corrosion resistance. Nanosecond pulsed laser is an efficient method for machining microchannels and holes in CFRP plates. The anisotropic heat transfer of CFRP leads to a complex mechanism of laser machining under different scanning directions (0°, 30°, 45°, 60°, 90°). A numerical model considering heterogeneity and anisotropy of nanosecond laser processing CFRP was established by COMSOL Multiphysics. By comparison of simulation and experiments under different scanning directions, the deviation of microchannel width between simulation and experimental ranges from 5.01% to 16.99%. The ablation mechanism of laser processing CFRP under different scanning directions was investigated. It demonstrates that the width of the heat affected zone (HAZ) and ablation increases with the scanning angle increasing, while decreasing with the scanning speed increasing. In addition, when compared to the scanning direction of 90°, the processing efficiency increases by 55.36%, while the width of the HAZ decreases by 55.01% when compared to the scanning direction of 0°. An optimal laser scanning speed of 630 mm/s is used to obtain the open hole with minimal HAZ and thermal damage.