| 摘要 |
PURPOSE:To eliminate generation of deformed portion, that is shear droop, on machined part by providing a shear angle on a cutting edge of at least one of male and female type dies of punching and performing joint punching machining in half blanking machining. CONSTITUTION:A punch unit 22 is formed so that the shape of its horizontal cross section is square and its lower face is formed on a face inclined by angle theta to the horizontal face. A work W is set on a female die 25 and a female die 20 is moved by effective stroke S, then as the work W is farer from the top A, machining amount becomes less due to shear angle given to the punch unit 22 of the female die 20. When the work is apart to the position near the dimension D of the punch unit 22, the machining amount becomes zero. Thus, non-strain punching machining can be attained by joint punching in half blanking. |
