A contactless energy transfer type of 3-DOF ultrasonic tool holder

•A 3DOF ultrasonic vibration tool holder was proposed for rotary ultrasonic machining.•Proposed tool holder achieve 1DOF, 2DOF and 3DOF vibration machining.•Structural optimization achieve multi-vibration integration and switching, high rotary speed practicality.•Machining effects of various vibration forms were compared.•Vibration mode affect the machining quality and tool life in grinding.•2DOF elliptic vibration has better comprehensive machining performance. The vibration form of the tool has a significant impact on the machining effect in rotary ultrasonic machining. Compared with 1DOF rotary ultrasonic machining, multi-DOF rotary ultrasonic machining have comprehensive advantages in the machining performance. However, the current multi-DOF rotary ultrasonic machining faces the challenges of miniaturization, multi-DOF vibration integration and high rotary speed. Therefore, a 3DOF ultrasonic vibration tool holder with decoupled three-channel contactless energy transfer was proposed, which realize 1DOF, 2DOF and 3DOF rotary ultrasonic machining with the same resonant frequency and the vibration conversion functions at high rotation speed. Structure design, principle analysis and simulation verification was carried out to determine the structure size and material. Through manufacturing and testing of prototype, the results show that under the performance of high speed, high transfer efficiency with 93 % and low temperature rise. The prototype of 3DOF ultrasonic vibration tool holder can not only integrate six vibration forms with high amplitude, but also has the function of replacing the milling tool for metal and grinding tool for brittle materials. Finally, through machining experiments with different vibration forms, two kinds of elliptical vibration produce regular textures with different shapes in the Ti-6Al-4V milling. In Al2O3 grinding, the surface roughness is the lowest under 2DOF vertical elliptical vibration grinding. While the 2DOF horizontal elliptical vibration grinding significantly improves the chip removal and prolongs the tool life. These findings provide guidance for machining performance under various vibration mode. It was proved that this tool holder integrated and switch with multiple vibration modes is of great value for high efficiency and high-quality multi-procedure machining. [Display omitted]