| 摘要 |
PURPOSE:To produce a high-accuracy optical glass element in high productivity, by applying a noble metal layer to a surface of a cemented carbide matrix composed mainly of WC, induction-heating the obtained forming mold and pressing a glass gob with the mold. CONSTITUTION:A forming mold used in the present process is produced by coating a cemented carbide matrix composed mainly of tungsten carbide (WC) with a noble metal layer having chemical stability to glass. The mold is heated by induction heating and a glass gob is pressed with the mold to effect the deformation of the surface layer of the glass gob contacting with the forming mold and to obtain the objective optical glass element. In the above molding process, the shape of the glass gob is selected to match the shape of the forming mold as far as possible. For example, in the case of producing an optical glass element having convex face, the radius of curvature of the glass gob should be larger than that of the forming face of the mold. The glass gob is ground with a grinding sand to attain the rough shape of the object and match the weight to the target weight and then subjected to polishing, etching or heat- treatment to smoothen the surface.
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