ABSTRACT
The glass blank was usually heated to a temperature dozens of degrees above the conversion point in a preheat device at first. Then, it was put into the mold with temperature, maintained at a lower level by a mechanical transport device, molded and annealed in the mold. When the inner stress was reduced to a certain extent, the lens was removed from the molding chamber through a mechanical conveying device, and then further cooled to room temperature in a cooling device. The whole process must be performed in a vacuum environment to ensure that the high-temperature glass is not oxidized by air.
