| 摘要 |
<p>The present invention provides a processing method for easily shaping a tip of a metal rod material such that the sectional area of the tip gradually decreases. A metal rod material (3) is contained in a molding groove (2) which is disposed in a mold (1) and whose end (2a) has a sectional area smaller than that of the metal rod material (3). A rolling roller (4) is rolled in contact with a mold surface (1a), and the rod material (3) is plastically deformed and molded is accordance with the shape of the molding groove (2). Subsequently, a burr (3b) is removed. The molding groove (2) has a sectional area smaller than that of the metal rod material (3) at the tip end (2a), has a width and depth larger in size than a diameter of the rod material (3) at the rear end (2b), and has a gradually decreasing sectional area towards the tip end (2a). In one embodiment, a rolling roller (14) rotates together with large-diameter rollers (15a,15b), and is pressed in contact with the mold surface (1a) by the rollers (15a,15b). In a further embodiment, a rolling roller (16) rotates together with a large-diameter roller (17), and a plurality of rolling rollers are supported by a retainer ring (18) disposed coaxially with the roller (17) at the outer periphery of the roller (17), arranged around its circumference, and pressed in contact with the mold surface (1a) by the roller (17). <IMAGE> <IMAGE> <IMAGE> <IMAGE></p> |
