摘要 |
A method is provided for controlling molding conditions of resin in the manufacture of articles such as optical lenses, which includes the steps of filling resin in a metal mold held at a temperature lower than a glass transition temperature of the resin, and then pressurizing the resin under comparatively high pressure so as to expedite hardening of the resin by raising its glass transition temperature, then reducing the pressurization of the resin to comparatively low pressure, and increasing, generally in association, the temperature of the mold cavity surface higher than the glass transition temperature of the resin so as to form a molten layer on a front face of the resin surface, and finally raising the pressurization of the resin to a medium pressure and lowering, generally in association, the cavity surface temperature of the metal mold so as to reduce the temperature for the withdrawal of the product.
|