Investigation on effect of ultrasonic vibration on micro-blanking process of copper foil

Investigations have revealed that size effect obviously affects forming quality and accuracy of micro parts. However, to find effective approaches that can reduce the influence of size effect is still a critical problem to be solved. Ultrasonic vibration has been widely used in industrial metal forming recently, and it has been proved that it is helpful for improving section quality compared with conventional blanking. In this study, micro-blanking process was carried out with a specially developed device. The square holes of copper foil T2 were investigated by analyzing the evolution of microstructure, crack initiation, quality of shearing surface, etc. Inhibition of crack initiation is found due to the softening effect in ultrasonic vibration assisted micro-blanking by analyzing section obtained under different ratios of blanking stroke to thickness ( h/t ), which increases the ratio of smooth zone. The analysis of microstructure in deformation area shows that a shearing deformation area becomes smaller, and radius of fillet decreases. Surface roughness of smooth zone decreases with ultrasonic vibration due to polishing effect. Compared with traditional micro-blanking, this compound plastic forming technology applying ultrasonic vibration on the punch can improve the section surface quality by increasing the ratio of smooth zone, and decreasing the surface roughness and fillet radius. The experimental outcomes reveal the mechanism of shearing deformation behavior during ultrasonic vibration assisted micro-blanking process of copper foil and the findings confirm that ultrasonic vibration can be regarded as a way to improve the forming quality of micro-blanking.