| 摘要 |
PROBLEM TO BE SOLVED: To provide a press forming method for improving the forming limit of a material by driving the local region of a press die as a movable punch and also forming a complicated shape product in the smallest possible number of stages while evading the failure of forming such as cracks and wrinkles. SOLUTION: Preforming is performed by performing the hold-down of a blank 4 with the die 13 and a blank holder 10 of a press forming apparats by using the press forming device having a die in which a movable punch 9 is incorporated, the nose of the movable punch 9 is brought into contact with a blank 4 in the state where the nose is projected and preceded in the stage where the press forming apparatus does not reach the bottom dead center and bringing in the blank in the position where a rugged region faced to the movable punch 9 is made on the side of the die. After that, when the press forming apparatus approaches the bottom dead center, the forming of the whole panel parts with the punch 6 and the die 13 is started and the blank 4 is formed into the final shaped panel parts while retreating to the die in accordance with the stroke of the press forming apparatus with the movable punch 9 pressured and press forming apparatus as the movable punch 9 is pressurized and held to the blank 4. COPYRIGHT: (C)2008,JPO&INPIT
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