Precision molding used in optical glass

Precision molding is a state-of-the-art technology for the volume production of complex lenses. Generally used mold materials in the molding process exhibit a thermal stability of up to 650°C. However, a variety of so-called low transformation temperature glasses (low Tg glasses) is required for the precision molding process.

To overcome the disadvantage of this process is that the surface of these pressings is still rough and the pressings therefore need additional grinding and polishing. Precision molding[/url] technologies for direct pressing of aspherical lenses have been developed in the past years worldwide.

The process of precise molding starts from a polished or firepolished preform. The surface of such a preform must be of very good quality with respect to surface roughness and defects. Such a preform can be a precision gob or any other polished
lens perform. During a precision molding process, the preform is shaped into its final geometry, while conserving the surface quality of the preform. The molding process is a low temperature molding process with typical temperatures between 500°C and 700°C.