A cutting force model based on kinematic analysis in longitudinal and torsional ultrasonic vibration drilling

The longitudinal and torsional ultrasonic machining (LTUM) is an emerging ultrasonic vibration machining method, which is an innovation method based on rotary ultrasonic machining (RUM). Compared with one-dimensional longitudinal ultrasonic machining (LUM), LTUM has better performances and promising applicability. In this research, the machining mechanism and a drilling force model in longitudinal and torsional ultrasonic vibration drilling is proposed based on kinematic analysis. Besides, the kinematic model and track model in LTUM are established. In addition, the dynamic characteristics and cutting characteristics of the abrasive grains in LTUM are analyzed. Meanwhile, the material removal model for fracture material based on the indentation fracture theory in LTUM is considered. Based on the kinematic analysis and material removal model in the longitudinal and torsional ultrasonic vibration drilling, the cutting force model is developed and the relationship of cutting force with processing parameters and material parameters is investigated. Eventually, the verification experiment is carried out on carbon fiber-reinforced polymer (CFRP)-T700. The experimental result shows that the developed cutting force model predicts the cutting force accurately and the deviation is less than 10% in CFRP drilling. Additionally, the drilling experiment of LTUM, LUM, and conventional drilling (CD) are carried out respectively, and drilling force in the three processes are compared. The comparative analysis results show LTUM is superior to LUM and CD with lower drilling force and better performance.