Study on exit damage characteristics of ultrasonic vibration assisted drilling of CFRP

In order to solve the disadvantage of tearing and burr damage in axial drilling of carbon fiber reinforced plastics (CFRP), the stiffness at the exit is increased by applying different drilling speed in ultrasonic vibration assisted drilling (UVAD) Firstly, compared with conventional drilling (CD), ultrasonic assisted vibration drilling can realize the separation of axial tool and tool/chip; Secondly, the cutting speed characteristics of ultrasonic assisted drilling at different speeds are analyzed, and the change of cutting speed characteristics of ultrasonic assisted drilling at low speed is obvious; Finally, the change trend of contact rate at different speeds is analyzed. The experimental results show that the stiffness of ultrasonic assisted vibration drilling is significant. Taking the speed of n = 100 r/min as an example, the stiffness of ultrasonic assisted drilling is about twice as high as that of rotary speed n = 2400 r/min, which is about 8% higher than that of ordinary drilling when n = 100 r/min; Hole exit quality of low-speed drilling: compared with CD, the tearing factor of ultrasonic assisted vibration drilling is lower. Therefore, this method provides a way to improve the hole quality of CFRP.