Abstract
As development of micro electro mechanical systems (MEMS) technology, microforming is gaining attention because of some advantages such as material and structural flexibility, low prices, and high production rate. However, forming accuracy is inferior to conventional semiconductor process. Because when the size of die structure is miniaturized close to gram size of the sheet metal, material flowability becomes non-uniform and it needs large forming load. So, in this study, in order to improve forming accuracy, lowering deformation resistance of work-piece materials and improving formability by ultrasonic vibration was focused on. Interesting effects occur when ultrasonic vibration is applied in the metal forming processes, including reduction in the friction between die and work-piece, a decrease in the forming forces and a decrease in the springback. So the ultrasonic vibration assisted micro-forging was performed on pure copper thin sheet metal to explore the forming load reduction effect and forming accuracy. The punch diameter was 2mm and the punch had 3 lines of micro V-grooves (the width of grooves were 200μm and 100μm). The frequency and amplitude of punch used in this study were 100kHz and 1.2μm, respectively. The results showed that forming accuracy increased about 4% and surface finishing was also improved by using ultrasonic vibration. These results indicated effectiveness of ultrasonic vibration assisted micro-forging.
