Effects of Rocking Motion Induced by Multiple Linear Actuators in Upsetting of Cylindrical Specimen into Rectangular Shape

Abstract

One of the authors confirmed that the flexible rocking motion induced by controlling four linear actuators effectively reduces the forging load. In this study, this technique was applied to die forging, and load reduction and the improvement of die filling were investigated. A cylindrical aluminum specimen was upset into a rectangular-hole die, in which a rocking motion was applied to the punch in the latter half of the stroke. Experiments were conducted by varying the diehole shape, rocking conditions and the amount of compression. The upsetting load obtained when applying a rocking motion with high frequency and small angle was reduced by approximately 50% compared with that without a rocking motion. Die filling around the rocking tool was promoted, resulting in non-uniform die filling along the compression direction. Total die filling was mainly affected by the amount of compression. The rocking direction and the side-length ratio of rectangles caused little differences in forging load and die filling.