Thrust force model for ultrasonic-assisted micro drilling of DD6 superalloy

As a typical refractory material, the DD6 nickel-based single-crystal superalloy has important applications in the aviation industry. Ultrasonic-assisted drilling is an advanced machining method that significantly improves machining of refractory materials. The drilling thrust force influences the hole surface quality, burr height, and bit wear. Therefore, it is necessary to predict the thrust force during ultrasonic-assisted drilling. However, there are few reports on the modeling of the thrust force in the ultrasonic-assisted drilling of micro-holes. A thrust force prediction model for ultrasonic-assisted micro-drilling is proposed in this study. Based on the basic cutting principle, the dynamic cutting speed, dynamic cutting thickness, and acoustic softening effect caused by ultrasonic vibrations are factored into this model. Through model calibration, the specific friction force and specific normal force coefficients were determined. The model was verified through ultrasonic-assisted drilling experiments conducted at different feed rates, spindle speeds, frequencies, and amplitudes. The maximum and minimum errors of the average thrust force were 10.5% and 2.3%, respectively. This model accurately predicts the thrust force based on the parameters used for ultrasonic-assisted micro-hole drilling and can assist in the analysis and modeling of DD6 superalloy processing.