Effects of process parameters in ultrasonic vibration assisted incremental sheet metal forming

Incremental sheet forming process (ISF) is a dieless forming method capable to produce small-batch of sheet metal components economically. This makes ISF attention-grabbing for research and development. Use of ultrasonic vibration is a modern approach implemented to improve ISF process. In this article¡ the effects of process parameters of ultrasonic vibration assisted incremental sheet forming (USVAISF) such as tool diameter¡ pitch size and vibration amplitude on forming force¡ fracture depth and percent reduction of forming force is investigated experimentally through response surface method. Results indicate that decreasing tool diameter and increasing ultrasonic vibration amplitude decrease the forming force and make the ultrasonic vibration more effective (increase the percent reduction of forming force) in USVAISF process. Fracture depth decreases with increasing pitch size and vibration amplitude. The influences of tool diameter on fracture depth and pitch size on forming force are complicated and different effects are seen in various conditions. Results show 33% to 63% reduction in forming force and 2% to 29% reduction in fracture depth in ultrasonic vibration assisted incremental sheet forming (USVAISF) compared with conventional ISF (without ultrasonic vibration). Eventually¡ optimal process parameters are predicted for ultrasonic vibration assisted incremental sheet forming and validated experimentally.