Finite Element Simulation of Filling Behaviors in Precision Glass Molding of Fresnel Glass Lenses

Precision glass molding is a promising yet challenging approach for fabricating Fresnel glass lenses, as their complex multi-ring microstructures tend to induce nonuniform glass flow and incomplete filling. To elucidate the filling behaviors under compression, a thermo-mechanically coupled finite element model was developed to simulate the molding process. The ring filling ratios of each ring and the total lens were adopted as a quantitative metric to systematically investigate the effects of molding temperature, molding pressure, glass–mold interfacial friction coefficient, and the number of Fresnel rings on glass flow and filling behavior. The results show that filling proceeds sequentially from the inner rings to the outer rings. Increasing the interfacial friction coefficient or the number of Fresnel rings significantly increases flow resistance, suppresses radial glass flow, and prolongs the filling time. In contrast, higher molding temperature and pressure promote glass flow, improve the filling efficiency of multi-ring microstructures, and identify the critical processing window for complete filling. These findings provide fundamental insights into the filling behavior of Fresnel microstructures during precision glass molding and offer a theoretical basis for process optimization and the high-precision fabrication of Fresnel lenses.