抄録
A newly developed ultra-fine micro piercing has been demonstrated successfully with only a few technical points that need improvement. The die material is mild steel and the strength of the die is equal or sometimes smaller than that of the pierced material. Therefore, pierced scrap accumulated in the die hole may stop the punch advancement. If the pierced material rises up unevenly from the die, a lateral force acts on the punch and the punch defect advances and thus results in shaving the surface of the hole. In this study, the advancing defects were suppressed by using a decompression chamber under the die. In doing so, the scrap is sucked away from the die hole at each stroke and the foil, material to be pierced, is pulled down through two holes that are 1mm apart from the die hole. The results of our experiment show a high precision continuous ultra-fine piercing process can be carried out with relative ease for various engineering materials.
