Modeling of burr height in ultrasonic-assisted drilling of DD6 superalloy

DD6 nickel-based superalloy is a typical refractory material, and has important applications in the aviation industry. Ultrasonic-assisted drilling can greatly enhance the processability of refractory materials. The presence of burrs will affect assembly, and the extra process to remove burrs will reduce production efficiency and increase production costs. Compared with conventional drilling, ultrasonic-assisted drilling can distinctly reduce the burr height. It is very necessary to model and predict the burr height of ultrasonic-assisted drilling. A prediction model of exit burr for ultrasonic-assisted micro drilling is proposed. A new thrust force model is developed by considering the dynamic cutting speed, dynamic cutting thickness, and the acoustic softening effect. The newly established ultrasonic-assisted drilling thrust force model was used to modify the conventional drilling burr height model, and the burr height was calculated. The accuracy of the model is verified by ultrasonic-assisted drilling experiments under different feed rates, spindle speeds, frequencies, amplitudes, and point angles of the bit. The minimum error of the average burr height prediction value is 4.5%, and the maximum error is 17.7%. The model has great significance in the prediction of burr height in ultrasound-assisted micro-hole drilling.