Analysis of flexibility in precision glass molding (PGM)

Abstract

The demand for precision glass optics with complex shapes has increased in recent years, primarily in sectors such as lighting technology, automotive, laser technology, and consumer electronics. This rising trend, combined with production costs, represents a major challenge for the industry as demand needs to be met in a cost-effective manner. To address this challenge, the industry had developed innovative solutions to remain competitive. Precision glass molding (PGM) has emerged as a promising solution for this purpose. PGM is a replicative manufacturing process that enables a cost-effective production of precise glass optics. In this process, a glass preform is heated up into a viscoelastic state and pressed between a pair of molding tools. However, the manufacturing process of the molding tools can be both time-consuming and expensive. Additionally, they are specifically manufactured to produce a certain lens design under a given set of molding parameters. During this investigation, we considered a molding tool pair used to produce a specific lens design. We varied the process parameters, such as pressing force and temperature, into several different combinations, and produced the lenses subsequently. The aim is to analyze the flexibility in the PGM process, and to determine whether different lens geometries can be produced with a pair of molding tools. The final shape of the molded lenses was measured using a profilometer, while the center thickness of the lenses was measured with an absolute digital measuring probe. Finally, the shapes obtained from the molded lenses were compared and analyzed. The pressing temperature and force have a considerable impact in the final shape, which can be tuned along with other process parameters to achieve a certain degree of flexibility in the molding process.