Consolidated contact lens molding

Abstract

An automated method and apparatus is provided to mold and cure soft contact lenses. At a first station, front curve mold halves are partially filled with a polymerizable monomer. At a second station, a surfactant coating may be applied to a flange on the front curve mold half to provide subsequent preferential adhesion of any excess hydrogel to a back curve mold half at the time the mold halves are separated. At a third station, the mold halves are assembled under vacuum, and clamped to displace any excess hydrogel from the mold cavity. This clamping step firmly seats the back curve mold half, severs any excess monomer from the monomer in the cavity, defines the lens edge, and seals the cavity in a vacuum. Following assembly of the mold halves, the assembly is transported to a precure station and reclamped, and the monomer is precured with actinic radiation, such as UV, to partially cure the monomer to a gel like consistency. The pallets of lens assemblies are transported through an extended cure station using heat and UV radiation to complete polymerization. The lens mold assemblies are then separated by applying a temperature gradient to the back curve mold half through the use of lasers or high energy steam and then pried apart in an automated station, with any excess monomer adhering to the removed back curve mold half. The front curve mold half, and the newly molded lens is then hydrated and separated from the front curve mold half in a subsequent apparatus.