Design of a novel integrated ultrasonic tool holder for friction stir welding

Ultrasonic vibration friction stir welding (UVFSW) has shown advantages in reducing welding defects and improving welding quality in aerospace, automobile, and power electronics. In this study, we design a novel 20-kHz integrated ultrasonic tool holder in FSW. The finite element model of FSW transducer is established, where the elastic modulus is measured by non-destructive acoustic. In the three transducer prototypes with alloy steel, the effect of prestress on resonant frequency is investigated and the ultrasonic vibration is measured. It proves that the resonant frequencies are well consistent between simulation model and the experiment by the elastic modulus testing and the prestress optimization. The ultrasonic amplitude of the pin is up to 24 μm. The experiment also indicates that the vibration is different with the steel material properties. Our findings can have a guidance to the design for a general ultrasonic actuator. The integrated FSW ultrasonic tool has potential to apply in a confined space in general machining equipment.