Residual stresses in glass after molding and its influence on optical properties

Compression molding of glass optics is gradually becoming a viable manufacturing process for high precision optical lenses. However, during cooling, glass properties undergo a small amount of changes due to structural relaxation. As a result, residual stresses are trapped inside the molded glass lenses. In this research, compression molded lenses were studied using the birefringence method assisted by the finite element analysis. The experimental and simulation results showed that compression molding process can be controlled to a very high precision providing that the proper cooling is applied during cooling. In addition, numerical analysis using finite element analysis also provides a better understand of the cooling process and offers an economic solution for process optimization for low cost glass lens production.