Effect of side die pressure and adaptive die temperature control in press forming of U-beam using carbon fiber-reinforced PA6 sheets

In this study, the die cushion of a mechanical servo press was innovatively used to apply a side pressure to the die during the press forming of a U-beam from stampable sheets, and the die temperature was controlled by a heat-and-cool oil system. The side die pressure, which was independent of the press pressure, was applied through the vertical sides of the U-beam by using the servo die cushion to slide the side wall of the die. The die temperature control system was used to heat the die slightly below the melting point of the resin in the stampable sheets, maintain the temperature of the sheets at the beginning of the press forming, and rapidly cool the sheets immediately after the forming. As targeted, the temperature control enabled sufficient deformation of the sheets, adequate removal of voids, and shortening of the processing time. The servo die cushion of the press machine was also confirmed to be effective for applying the side die pressure during the forming.