A prediction model for drilling temperature of CFRP/Ti stacks and green cooling strategy considering chip ejection process

Abstract

Drilling temperature has always been a hot issue in the drilling process of CFRP/Ti stacks. Accurately predicting drilling temperature is necessary for reliable optimization of drilling parameters. However, since the drilling process involves two materials and may affect each other, the prediction of temperature during drilling is still a challenge. In this paper, a novel drilling temperature model is established to predict the temperature distribution in CFRP workpiece during the drilling process of CFRP/Ti stacks, considering the minor cutting edge and titanium alloy chip ejection process. Specifically, according to different drilling phases, in addition to considering the heat source of the cutting zone of different materials, the heat source generated by the interaction of minor cutting edge and rebound hole wall of CFRP and the heat source formed by the thermal-mechanical effect of Ti chip ejection process are also considered. The results show that the prediction errors of peak temperature in CFRP entrance and stack interface region during drilling are within 15.8 % and 10.9 %, respectively, which indicates the validity of the model. Finally, the green cooling strategy (High and low frequency compound vibration-assisted drilling) is adopted to significantly reduce the peak temperature in the drilling process by controlling the chip morphology and ejection process, which further proves that the thermo-mechanical action of Ti chips on CFRP cannot be ignored, and provides reference for temperature modeling and low-damage processing of CFRP/metal stacks.