| 摘要 |
PROBLEM TO BE SOLVED: To obtain a blanked product with a whole sheared face having a minute shear droop. SOLUTION: This method uses a flat die 13 arranged with a hole 13a having the same shape as that of a product to be blanked, an ejector 14 slidably fitted into the hole 13a of the flat die 13, a blanking punch 15 having a hole 16a to which the tip part of the blanking punch 15 is fitted freely slidably and having a shape slightly smaller than the hole 13a at the tip part and a die 16 with protrusion having a protrusion 16b imparted with an inner peripheral face shape slightly larger than the hole 13a. At the beginning, at a state the tip part of the blanking punch 15 is retracted from an inner peripheral face side cavity 17 of the protrusion 16a of the die 16 with protrusion, a stock A is squeezed and then sheared by an inner peripheral side corner 16c of the protrusion 16b to be filled into the inner peripheral face side cavity 17. Successively, while maintaining squeezing of the stock A, the blanking punch 15 is advanced into the inner peripheral face side of the protrusion 16b and the hole 13a of the flat die 13, and the stock A is sheared/separated by the tip outer peripheral corner 15a of the blanking punch 15 and the opening edge corner 13b of the hole 13a of the flat die 13.
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