| 摘要 |
<p>PROBLEM TO BE SOLVED: To blank a base plate from plate stock in a manner as to obviate the formation of slug. SOLUTION: A half-blanking stage of applying a punch on the surface of either front or rear of the plate stock, applying a die on the other surface, recessing the one surface of the plate stock and projecting the other surface by means of such punch and die, forming a first shearing surface on the peripheral surface of the recessed part and forming a second shearing surface on the peripheral surface of the projecting part is executed as the method for blanking the plate stock. A stage of returning the projecting part of the plate stock subjected to the half-blanking stage is executed. The punch is placed on the one surface of the plate stock subjected to the returning stage and the die is applied on the other surface. The other surface of the plate stock is recessed and the other surface is projected by means of such punch and die. A third shearing surface is formed on the peripheral surface of the recessed part and a fracture surface is formed in continuation with the third shearing surface. The fracture surface is made continuous with the first shearing surface.</p> |
