A Novel Heat Shrinkable Ultrasonic Transducer for Rotary Ultrasonic Micro-nano Precision Manufacturing

Rotary ultrasonic machining (RUM) has been proven to be a suitable technology for micro-nano precision manufacturing for hard and brittle ceramics/composite materials. However, the working frequency of the ultrasonic transducer in current RUM is in range from 20 kHz to 30 kHz. Moreover, the tool is tightened by an elastic chuck, which is in low clamping precision, high radial run-out, and unstable ultrasonic energy transmission. In this paper, we developed a novel heat shrinkable RUM ultrasonic transducer with 60 kHz frequency by equivalent circuit and finite element method (FEM). An analytical electromechanical equivalent circuit model was deduced to obtain the initial structure dimensions of the ultrasonic transducer. Three flange mounting structures were proposed to optimize and improve the energy transmission at the working resonant frequency. The influence of the proposed flanges on the resonant frequency of three transducers was analyzed and presented. The designed transducers were manufactured and tested in experiment. It shows that resonant frequencies of these three transducers with step, circular, and plate flange are 62.2 kHz, 61.46 kHz, and 61.4 kHz, and vibration amplitudes in 90 V driving voltage are $1.33\mu \text{m}$ , $4.74\mu \text{m}$ , $5.33\mu \text{m}$ , respectively. The working resonant frequencies by experimental measurement are consistent with the calculation result of the equivalent circuit and FEM. Moreover, the plate flange transducer shows the optimal amplitude capability with enough ultrasonic energy in micro-nano precision manufacturing.