Abstract
The glass molding process (GMP) can press glass perform into a shape of finished lens under high pressure and temperature conditions, and it is easy to achieve mass production. So, it has emerged as a promising alternative way to produce complex shapes lens. It is well known that viscoelastic is one important properties of glass at high temperature. In this study, A 4-pair generalized maxwell model was used to express viscoelastic of glass, and model parameters were obtained by fitting the relaxation curve obtained from experiment. The finite element models were established by MSC.MARC, the correctness of the FEM models and its used model parameters were verified by the cylindrical compression experiments. Finally, the simulations of glass lens forming stage were performed under different conditions. Stresses distribution were predicted by FEM, it was found that the maximum stress at the edge of lens, which make lens rupture easily at this zone. It was also discovered that the molding temperature is higher, the less stress, and the molding velocity is higher, the higher stress.
Highlights
Aspherical lens are increasingly being used in many products, such as medical and scientific instruments [1, 2]
In order to attain the parameters of generalized Maxwell model for Finite element method (FEM) simulation, the cylindrical sample with diameter and height of 10 mm was heated to 560°C, and pressed at a velocity of 5 mm/min until the load was up to the specified 400 N
Fig. (6) shows the comparison of stress relaxation between experiment and simulation at different temperatures (a)560°C (b)580°C. It can be found from the figure that the predicted data obtained from the FEM show a good agreement with the measured results, which shows FEM can be used for modeling viscoelastic material behavior during lens molding and the obtained model parameters is feasibility
Summary
Aspherical lens are increasingly being used in many products, such as medical and scientific instruments [1, 2]. Traditional ways to produce lens are not suitable mass production and dangerous to environment, an new manufacturing process is needed that can produce high precision aspherical lens. The glass molding press(GMP) has been a effective and economical alternative way to produce complex shapes lens gradually, more and more researchers pay attention to this technique [3, 4]. The purpose of the present investigation is to built a validated FEM model to study the process parameters during lens molding process. The cylindrical compression tests were done to attain model parameters. The numerical simulation of the aspherical lens forming process were simulated, the stress distribution in the lens and its influence factors were analyzed and discussed
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
