PURPOSE: To manufacture tooth form parts, etc., of which whole surface is a sheared section without roll over.
CONSTITUTION: A first working process is such that a sheet metal 100 that is set in a first die is worked for a half blanking for a first target shearing contour CONT 1 by a first punch having a negative first clearance, a return working force is applied on the metal from the bottom, and a first semi-finished article 200 and scrap are separated. A second working process is such that the first semi-finished article 200 which is turned upside down and set in a second die is pressed by a second punch having a negative second clearance, and, while a roll over due to the first working process is crushed, a shaving is performed for a second target shearing contour CONT 2 to obtain a second semi-finished article 300. A third working process is carried out, successively in this order, such that the second semi-finished article 300 on a third die is pressed by a third punch 11C having a positive third clearance and that a shaving is performed for the final shearing contour CONT 3.
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