To manufacture a metallic member having a closed section by a relatively simple method while suppressing occurrence of spring-back.
A punch 42 is moved in a state that a metallic plate workpiece W1 is held by a blank holder 41 with respect to a die 45; the plate workpiece is press-formed in a projecting shape, and a projecting part projected in the opposite direction is formed on a projecting top face part W2. The projecting part of the press-formed plate workpiece is press-formed in the projecting direction in a projecting shape of the plate workpiece by a core die. Both projecting side face parts W3, W4 of the projecting top face part of the plate workpiece are inwardly displaced, respectively, to form a closed section. When manufacturing a member having the closed section from the metallic plate workpiece, the plate workpiece holding force for holding the plate workpiece with respect to the die by the blank holder is set to be smaller during the projecting part forming when the projecting part is formed as compared with the time when the press forming starts, where the plate workpiece is press-formed in the projecting shape.
ISHIDA YASUAKI
MIZOGAMI TATSUSHI
Mitsuo Tanaka
Masahiro Ishino
Mikio Takeuchi
Haruo Nakano
Kawabata Junichi