| 摘要 |
PROBLEM TO BE SOLVED: To simplify a die structure forming an inverse portion in a flanged portion of plate material. SOLUTION: In the plate material W setting in a die B for inverse bending, the flanged portion Wf is bent in right angles in advance in a right angle bending process as a previous process, and a recessed groove Wg is also cut in a portion becoming a ridge portion in the inner face of the flanged portion when inverse bending is performed. Consequently, an inverse portion Wi, in which the recessed groove Wg becomes a ridge line, can be easily bent so that a tip side of the flanged portion Wf is only pushed from its outward periphery by an inverse bending die 17 in an inverse bending process.
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