Abstract
In multi-stage closed die forging, an optimum shape of a preform is required to economically manufacture more complicate and precise products. This preform promotes to distribute an appropriate volume, and it helps to reduce material loss and forging load at the final stage for the final products. However, it is difficult for beginners to design the preforms, especially, in processes of locally-lateral upsetting. The preform is needed to make automobile parts such as a connecting rod, a crank shaft, and a knuckle arm. In this paper, locally-lateral upsetting of a rod billet for the typical preform is tried by using different punches and configuration to promote the asymmetric flow of the work material. The punch has each cylindrical nose with a different radius. Furthermore, the punch is set at a different rotating angle from the axial direction of the rod to promote the asymmetric material flow. As the results, the largest asymmetric material flow is appeared when the cylindrical punch with the large radius and rotating 45° is used.
