Simulation of Ring Blank Drawing by Finite Element Method

Ring-shaped oil seals used in automobiles are usually manufactured by the press drawing and the press blanking considering the shape and the use application. In this process of manufacturing, the material availability is quite low because the central region part is cut from the product and becomes the waste material. We propose the forming method by the press drawing using a ring-shaped blank for the metallic part of the oil seal in order to improve the material availability and reduce the number of processes. In this research, the forming accuracy using the ring-shaped blank was investigated by the forming simulation. As the result, when the knockout was fixed in order to generate the sufficient bottoming by the punch, it was found that the bottom part can be formed flatly and the angle part can be formed almost right. Furthermore, it was found that the inside diameter of the formed product is proportional to the inside diameter of the blank except the case when the bottom part of the formed product is small. Hence, the required inside diameter of the ring-shaped blank can be calculated with the proportional relationship.