| 摘要 |
PURPOSE:To prevent buckling or wear of a punch and to overcome the problem of short life of a metal mold, by using a push punch for taper holes and a die with escape hole. CONSTITUTION:The punch 1 having a tip portion 1D with taper 1a is pressed downward so as to descend, while sliding inside the hole 3a of a stripper 3, whereby the material plate 4 is subjected to hole punching. At that moment, the material 4a which is extruded by the punch can escape into the hole 2a of the die 2, so that the punching resistance is minimized. Then, the stripper bar 7 is pushed up to act upward and remove the machined work from the die 2. The protrusion 4a is thereafter removed by grinding or cutting, thus obtaining a small diameter hole 6. |
