Patent ID: 8166854

Claim:
A method for processing a predetermined portion of a plate-shaped work piece into a predetermined shape, the work piece having a top surface, a bottom surface, and an outer peripheral face, the predetermined portion corresponding to scraps to be removed, the method comprising: arranging a die and a pad to clamp the work piece therebetween; arranging a punch relative to the die and pad, the punch integrally having a constraining portion, the constraining portion having a contact surface that is continuous with a pressing surface of the punch; applying a shearing force to the work piece via the pressing surface of the punch, wherein the bottom surface of the work piece corresponding to the pressing surface of the punch is unsupported during shearing, said unsupported bottom surface defining the scraps when the shearing force is applied, wherein arranging the punch includes positioning the contact surface of the constraining portion so as to contact the outer peripheral face of the predetermined portion of the work piece while the work piece is clamped between the die and the pad, thereby providing a reactive force restraining the outer peripheral face from moving in an outward direction perpendicular to a thickness direction when the shearing force is applied; and allowing the scraps to automatically fall away as the shearing force is applied.