| 摘要 |
PROBLEM TO BE SOLVED: To provide pressing technique by which the cost is reduced. SOLUTION: With this press device, a planar material 45 to be worked is formed into a columnar body having a cross-sectional shape the whole width of which is larger than an opening part by repeating press working using a plurality of sets of press die groups in which a concave die and a punch 33d having a pressing surface at its tip are made one set. The pressing surface 33f of the punch of at least one of the press die groups is larger than the opening part of the material to be worked in the pressing state with the press die. When the press device is constituted in such a way, because working is performed by bringing the pressing surface of the punch 33d into contact with the material to be worked in wide area and the deformation of the material 45 to be worked in each press working is made larger, the number of the press working to the final stage is reduced. When the number of the press working to the final stage is reduced, the number of the press dies to be prepared is reduced, so the reduction of the cost is enabled.
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