Over the past two decades, precision glass molding has gradually become a competitive hot-replicating manufacturing technology for precision glass optical components. But form errors occur on surface of molded glass optics as a result of a diverse range of effects including viscoelastic relaxation and thermal shrinkage of optical glass material during the molding and cooling processes. Conventionally these errors can be compensated solely via time-consuming and cost-intensive try-out molding experiments. The target of this thesis was to provide an efficient substitution by developing of a quantitative numerical method to model the precision glass molding process. With this method, the final shrinkage error can be predicted before the actual mold manufacturing commences. To achieve this goal, systematic research was required on the development of reliable thermal and structural models based on system analysis, measurement of key material properties and the qualification of this model through diverse case studies. The process simulation was developed in a commercial FEM code, in the form of a combined metaphysical model. Maxwell model and the Arrhenius shift function were used to calculate the viscoelastic deformations of the glass material. The contact conditions, heat conduction, friction and other boundary conditions are factored into calculations, based on a system analysis of the molding process. In addition, the determination methods for relaxation behavior of glass and its temperature dependency, effective thermal conductivity and coefficient of thermal expansion of applied optical glass material as well as the friction behavior between glass and mold material at high temperature were successfully developed on a commercial production machine and can be standardized for further glass-mold material combinations. Towards the end of the thesis, the developed numerical simulation method was applied to several case studies including a range of aspherical lenses, a cylinder lens array and free form lenses. Comparison of the geometrical deviations obtained in both the simulation and experimental approach showed good coherence and most deviations in-between were less than 2 μm. With the developed numerical simulation model and property measurement methods, this research provided the optical manufacturers an opportunity to achieve a lower production cost and a shorter development time by compression molding of precision glass components.
Details
Autor Wang, Fei
Lieferzeit 3-4 Tage
Gewicht 0.3 kg
Erscheinungsdatum 22.04.2014
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Prozesstechnologie

Wang, Fei

Simulating the Precision Glass Molding Process

ISBN: 978-3-86359-193-9
39,00 €
inkl. 7% MwSt.

Kurzbeschreibung

Over the past two decades, precision glass molding has gradually become a competitive hot-replicating manufacturing technology for precision glass optical components. But form errors occur on surface of molded glass optics as a result of a diverse range of effects including viscoelastic relaxation and thermal shrinkage of optical glass material during the molding and cooling processes. Conventionally these errors can be compensated solely via time-consuming and cost-intensive try-out molding experiments.
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