Vibration-assisted cutting of thermoplastic CF/PEEK: understanding the cutting mechanism and temperature field evolution

Vibration-assisted cutting (VAC) is an effective way of improving machining quality. Through vibration-assisted cutting experiments, the cutting mechanism of carbon fiber-reinforced polyetheretherketone (CF/PEEK) composites during vibration-assisted cutting and the influencing factors on the quality of machined surfaces were investigated. The effect of cutting-directional vibration-assisted (CDVA) and normal-directional vibration-assisted (NDVA) on cutting force, cutting temperature evolution, chip and surface morphology were analyzed. The experimental results demonstrate that compared with the traditional cutting (TC), the cutting ability of the tool in VAC was enhanced. When the fiber orientation is 0°, 45°, 90° and 135°, the maximum reduction of cutting force in CDVA is 36.48%, 23.43%, 27.19% and 13.04%, and the maximum increase of cutting temperature in NDVA is 23.91%, 28.88%, 14.07% and 19.82%, respectively. VAC can effectively cut fibers and reduce machining damage, and the quality of machined surface is the best in NDVA. Intermittent cutting with vibration in the direction of the main cutting force results in shorter chip contact times and thus lower chip temperatures in CDVA. This study provides insight into the ultrasonic vibration-assisted cutting performance of CF/PEEK and offers ideas for the next generation of high-performance manufacturing of composite materials.