Processing quality of the hybrid of laser and gas-waterjet for CFRP hole cutting: An experimental study on the effects of gas and waterjet parameters

Hybrid of laser and gas-waterjet (HLGW) is a promising method for processing CFRP plates owing to the advantage of lower thermal damage and higher removal rate, but the literature is mainly focusing on linear cutting. This study investigated the effects of waterjet pressure, gas pressure, and waterjet impact angle on the processing quality of CFRP plates using this method. Hole quality at the entrance and exit was evaluated by the processing damage zone (PDZ), the roundness error, the micro and macro morphologies, and the taper. The results show that the hole quality at the entrance is more determined by the parameters, compared with the quality at the exit. Moreover, the overall average sizes of the PDZ are reduced by 13.8 % and 6.2 % at the hole entrance and exit respectively, when the waterjet impact angle is increased from 50 degrees to 60 degrees. The match of gas pressure and waterjet pressure significantly affects the hole quality, and the minimum PDZ, roundness error, and taper are obtained under different matches. Fiber crushing and matrix covering almost can be eliminated under gas pressure of 0.7 MPa. Besides, gas pressures of 0.5 and 0.7 MPa generally result in a smaller roundness error at both the entrance and exit. The minimum hole taper achieved is 0.1057, under waterjet impact angle of 60 degrees, waterjet pressure of 10 MPa, and gas pressure of 0.7 MPa.