Carbon fiber reinforced composites (CFRP) have the characteristics of high specific strength, corrosion resistance, and low density, and are widely used in aviation and military fields. Compared with traditional laser processing, the waterjet guided laser has little effect on CFRP thermal injury and has a large depth capability, waterjet guided laser processing has greater application prospects in CFRP. In this paper, high-power waterjet CW lasers at 532nm wavelength were used to cut CFRP. The variation of CFRP cutting depth and cross-section Heat-Affected Zone (HAZ) under different duty cycle and frequency was studied. Confocal laser scanning microscope was used to observe the three-dimensional morphology, cross-sectional thermal influence and fiber damage of the trench. The experimental results showed: The cutting depth and HAZ of CFRP increased with the increased of duty cycle. When the duty cycle increased from 20% to 40% at 10 kHz at 300 W laser power, the cutting depth was increased by 88.7%, and the maximum HAZ of the cross-section was increased by 56.3%; when the frequency increased from 10 kHz to 20 kHz at the 20% duty cycle of the laser power of 300 W, the cutting depth was increased by 11.9%, and the maximum HAZ of the cross-section was decreased by 16.6%. According to the results of CFRP cutting experiment, the duty cycle had a large influence on the cutting depth and the maximum HAZ, while the frequency had little influence on the cutting depth and the maximum HAZ. Large duty cycle could lead to damage to carbon fibers and high frequency lead to an increased in melt. The damage degree of fiber caused by duty cycle was more obvious. This study can provide technical guidance for cutting CFRP with high power waterjet guided CW laser.
|