純アルミニウム円管の揺動回転内フランジ成形法と成形限界

抄録

Although the possibility of orbital rotary forming of tube-end has been reported for an outward-flange having large value of flaring ratio, the possibility has not been illuminated previously for an inward-flange having large value of nosing ratio. In order to clarify the possibility of the inward-flanging, an orbital rotary forming process in which an inward-flanged shell is formed from a tube by means of rotary conical nosing and subsequent orbital rotary flanging has been proposed. Hard aluminum tubes are formed to inward-flanged shells, and the deformation behavior is examined. It is found that the inward-flange having large value of nosing ratio can be formed from a tube by means of the proposed process. The proposed method with a retainer ring which prevents buckling is found to be effective in improving the nosing limit. The inward-flanging limit of the proposed method is superior to those of conventional inward-flanging methods, such as spinning and press forming. Furthermore, the proposed method with a retainer ring seems to have a significant effect in making the flange thickness more uniform.