Using rolling sliding principle, bending groove is designed to be respectively around the shaft touch around the opening of the rotation of ball, left and right each one, as figure real shown, mold does not work, left and right die working surface in the same horizontal plane. When the bending punch is faced with the bending process, the left and the right balls are rolled, forcing the material to be pressed down under the rolling state, which is the material to produce the bending...
