Control of rollover of sheared edge in punching of high strength steel sheets

Abstract The rollover along the contour line on the separated edge of a punched product is not homogeneous especially when the counter shape of the punched product is locally concave or convex. This variety of rollover is adverse for the following processes such as hole expanding or deep drawing. Therefore, it is necessary to develop a punching technology to assure the magnitude of the rollover homogeneous along the counter line. An improvement of the punch profile in its axial direction as a method to control rollover was adopted and the performance of the punch was tested by the experimental approach with high strength steels.