| 摘要 |
PROBLEM TO BE SOLVED: To obtain a metal mold having durability and to obtain inexpensive products by utilizing the metal mold in possession by spreading a cloth material having stretchability between both sides of a V-groove of a lower mold, thereby preventing the bending flaws generated at the time of bending of a plate material. SOLUTION: The cloth material which has the stretchability and is knitted of liquid crystal polymer fibers having strength of several times that of iron and fibers of a fully aromatic polyester system and aromatic polyamide system of <=530 in denier is preferably spread between both sides of the V-groove. The cloth material 4 is spread between the upper mold 2 and lower mold 1 in possession under use. The cloth material 4 is stopped at several points by means of tapes, etc., to a lower mold 1 or the lower mold mounting base. The plate material to be subjected to bending is put between the upper mold 2 and the cloth material 4 and is subjected to bending. Since the cloth material has the stretchability, the cloth material restores to the home position after bending even if the cloth material is pulled to the V-groove at the time of bending. The pulling of the cloth tapes fixing the material and the peeling of the cloth material do not occur. The cloth material is merely necessitated to be kept rounded when not used. The repetitive use thereof is thus possible. The cloth material is soft but has the strength several times that of the iron and is, therefore, durable.
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