Method and equipment for mould-pressed glass product

Abstract

On molding a glass product by pressing a glass gob by the use of a mold composed of upper and lower dies each of which has a molding surface, a molten glass is supplied as the glass gob onto the molding surface of the lower die. Cooling is carried out for an upper surface of the glass gob supplied onto the molding surface of the lower die. After the cooling, heat radiation suppression is carried out to suppress heat radiation from the glass gob so that an inner part and an upper part of the glass gob are close in temperature to each other. Thereafter; the glass gob is pressed by the molding surfaces of the upper and the lower dies when the glass gob has a viscosity within a range between 103.5 and 106.5 poises (dPa.s). Preferably, the heat radiation suppression is carried out by making a heat shielding member lower in temperature than the inner part of the glass gob approach the upper part of the glass gob in a non-contact state.

Description

technical field [0001] The present invention relates to a method and apparatus for molding glass articles such as optical lens blanks, and more particularly to a method and apparatus for a so-called direct molding system in which molten glass is fed into a mold in which it is pressed. type. Background technique [0002] As a method of molding glass semi-finished products (hereinafter referred to as lens blanks), a direct pressing system of a method of grinding and polishing a lens blank into a glass product such as an optical lens or a state before a final glass product, due to its high productivity high, and thus widely used. In a direct pressing system, glass material is melted in a furnace into molten glass. A suitable measure of molten glass is sheared using a knife such as scissors and fed into a die (die). The molten glass added to the lower mold forms glass gobs with a generally marble shape under the action of its surface tension. The lower mold with the glass go...

AI Technical Summary

Problems solved by technology

However, these documents do not disclose a method that can effectively reduce the temperature difference between the inner and outer peripheral parts of the molten glass that causes the occurrence of the lower dent marks.

Images