PREPARATION OF PRECISION PUNCHING DIE

摘要

PURPOSE:To improve the accuracy of a punching die by incorporating only one part of a punch and die in a press by executing hardening thereon and after setting the diameters of both by inserting the punch to the die hardening the other part of unhardened blade tip part. CONSTITUTION:The punch 2 having outer diameter R is hardened after its forming and the unhardened die 3 whose inner diameter is smaller than a punch outer diameter R is prepd. The punch 2 and die 3 are included by opposing to a press die and the punch 2 is first inserted into the die 3 to set the inner diameter r2 to the outer diameter R of the punch 2. The punch 2 is then separated from a die 13 by ascending it to effect hardening on the blade tip part 13b of the die 13. A die 23 after hardening has almost no variation at its inner diameter r3 with the inner diameter r2 of the die 13 and the difference and clearance from the outer diameter R of the punch 2 are almost equal to zero. The dimensional error of punching die is thus eliminated to improve the accuracy.