Glass material model for the forming stage of the glass molding process

Tsai, Yu Chung; Hung, Ching-Hua; Hung, Jung Chung

doi:10.1016/j.jmatprotec.2007.11.294

Cited by 27 publications

(17 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some used measured thermo-viscoelastic properties of the materials (BK-7 and TaF-3 [75]), obtained the viscoelastic property of glass by using the relaxation data from a cylinder compression test with the assumption of incompressibility [76], or treated glass as an elasto-viscoplastic material to account for the strain rate effect [79]. In most of these works the temperature-dependent rheology was modeled by the classical phenomenological Vogel-Fulcher-Tammann equation [37] or the thermos-rheological simple assumption [75,77], in which the parameters need to be obtained by curve fittings to a series of viscosity tests.…”

Section: Constitutive Modeling Of Optical Glassmentioning

confidence: 99%

Precision glass molding: Toward an optimal fabrication of optical lenses

Zhang

Liu

2017

Front. Mech. Eng.

View full text Add to dashboard Cite

It is costly and time consuming to use machining processes, such as grinding, polishing and lapping, to produce optical glass lenses with complex features. Precision glass molding (PGM) has thus been developed to realize an efficient manufacture of such optical components in a single step. However, PGM faces various technical challenges. For example, a PGM process must be carried out within the super-cooled region of optical glass above its glass transition temperature, in which the material has an unstable non-equilibrium structure. Within a narrow window of allowable temperature variation, the glass viscosity can change from 10 5 to 10 12 Pa$s due to the kinetic fragility of the super-cooled liquid. This makes a PGM process sensitive to its molding temperature. In addition, because of the structural relaxation in this temperature window, the atomic structure that governs the material properties is strongly dependent on time and thermal history. Such complexity often leads to residual stresses and shape distortion in a lens molded, causing unexpected changes in density and refractive index. This review will discuss some of the central issues in PGM processes and provide a method based on a manufacturing chain consideration from mold material selection, property and deformation characterization of optical glass to process optimization. The realization of such optimization is a necessary step for the Industry 4.0 of PGM.

show abstract

Section: Constitutive Modeling Of Optical Glassmentioning

confidence: 99%

Precision glass molding: Toward an optimal fabrication of optical lenses

Zhang

Liu

2017

Front. Mech. Eng.

View full text Add to dashboard Cite

show abstract

“…Tsai et al 3 separated the viscoelastic property of glass material into the elastic part and the viscous part using the elasto-viscoplastic model based on the yielding stress. Material models have been used to examine glass behavior during this stage.…”

Section: Glass Materials Models Of the Embossing Stage Of The Conventimentioning

confidence: 99%

Modeling the Embossing Stage of the Ultrasonic‐Vibration‐Assisted Hot Glass Embossing Process

Nguyen

Hao

et al. 2014

Int J of Appl Glass Sci

Self Cite

View full text Add to dashboard Cite

Ultrasonic vibration technology has recently been applied in high‐temperature forming processes, such as hot upsetting and hot glass embossing. Experimental research has delineated the effects of ultrasonic vibration on reducing required forces and improving the formability of materials. The purpose of this study was to construct a finite element model of the embossing stage of the ultrasonic vibration‐assisted hot glass embossing process. Traditional hot embossing experiments in which the embossing speed and temperature were varied were performed to calculate the viscoelastic dissipation caused by ultrasonic vibration, and this value was then inputted into the simulation. The consistency of the force responses in the experiments and simulation indicated that the proposed model is valid. The findings indicate that the influences of parameters such as the vibration frequency, vibration amplitude, and embossing speed on the ultrasonic vibration‐assisted hot glass embossing process must be investigated further.

show abstract

“…The results revealed that the temperature inside the glass during the cooling stage had a considerable influence on the lens shape and internal stress. Additionally, Ananthasayanam and Tai et al indicated that temperature non‐uniformity may have a significant effect on deformation of the glass sample. Xie et al investigated the relationship between heating time and surface morphology.…”

Section: Introductionmentioning

confidence: 99%

Temperature effect on the deformation and optical quality of moulded glass lenses in precision glass moulding

Huang

et al. 2019

Int J of Appl Glass Sci

View full text Add to dashboard Cite

The aim of this study was to thoroughly investigate the effect of temperature on the deformation behavior and optical performance of moulded glass in a nonuniform temperature field. Experiments and numerical simulations were used to analyze how different temperature gradients distributed across a glass cylinder affected the deformation behavior of the moulded glass. Additionally, the imaging quality of the moulded glass lens was detected using the optical measurement system. The results show that the overall shape of the moulded glass cylinder was mainly determined by the value of the temperature gradient. The larger temperature gradient led to smaller deformation angle θ in the moulded glass cylinder. Temperature difference inside the glass dominantly affected the deformation behavior and surface morphology in the nonuniform temperature field, which greatly determines the imaging quality of glass lenses. The results of this study are significant for glass lens fabrication.

show abstract

Glass material model for the forming stage of the glass molding process

Cited by 27 publications

References 10 publications

Precision glass molding: Toward an optimal fabrication of optical lenses

Precision glass molding: Toward an optimal fabrication of optical lenses

Modeling the Embossing Stage of the Ultrasonic‐Vibration‐Assisted Hot Glass Embossing Process

Temperature effect on the deformation and optical quality of moulded glass lenses in precision glass moulding

Contact Info

Product

Resources

About