| 摘要 |
PURPOSE:To reduce wasteful use of material and to achieve a manufacturing method suitable for mass production by a method wherein annular pieces of material, obtained by dividing a nonmagnetic soft metal tube into a prescribed cubage using a tool having plural V-shaped annular protruding sections, are formed by applying pressure. CONSTITUTION:A nonmagnetic soft metal tube such as aluminum tube 12, for example, is fixed on a rotating axis 13 of a lathe or the like and a tool 17 having plural V-shaped annular protruding sections is attached to a supporting rod 16 which is movable in parallel to the rotating axis 13. With the tool 17 pushing to the aluminum tube 12, the tube is cut and an aluminum ring 18 of the same cubage as a magnet presser plate 3 (finished products) is obtained. Then, said aluminum ring 18 is formed by applying pressure into a rolled annular material, a specified protruding section 4 is pressure-formed and a magnetic press-plate 3 is obtained. |
