| 摘要 |
PURPOSE:To enable to mold an extremely small diameter O ring, by providing relief spaces consisting of a semispherical hollow part and an annular groove whose cross section is semicircular respectively on the inside and the outside of the annular groove for molding of the O ring whose cross section is semicircular. CONSTITUTION:Properties that a material is etched extending over a little wider area than a resist pattern when etching has been performed by spending time are used for the titled manufacture. A photomask 5 having the resist pattern of a circular part 3 and circular linear parts 2, 4 is placed on a metallic material 7 concentrically from the center and etching treatment is performed by spending appropriate time. The metallic material is etched extending over a little wider area than the pattern and a mold having an annular groove 10 for molding an O ring, a semispherical hollow part 8 for reliefing the surplus material to the inside and the outside and an annular groove 9 whose cross section is semicircular is obtained. It is possible to mold an extremely small diameter O ring whose inside diameter is about 0.55mm. and thickness thereof is about 0.4mm. according to this mold. |
