Simulation of an Aspheric Glass Lens Forming Behavior in Progressive GMP Process

Chang, Sung Wook; Lee, Young Min; Jung, Tae Sung; Kang, Jeong-Jin; Hong, Seok-Kwan; Shin, Gwang Ho; Heo, Young-Moo

doi:10.1063/1.2740950

Cited by 17 publications

(19 citation statements)

References 1 publication

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“…Chang et al [13] simulated a glass molding process where glass is modeled as a power-law strain-rate hardening material, which does not account for the time dependence of stresses and strain. A cylindrical compression test was performed on the glass at elevated isothermal temperature.…”

Section: Figurementioning

confidence: 99%

“…The thermal expansion behavior of glass is more complex than that of the molds and involves more parameters than a simple coefficient of thermal expansion, ' ' The structural relaxation experiments, the corresponding TNM model Table 2 The three stress relaxation definitions of the molding glasses used in the current study Shear relaxation function, (13) and the implementation in the finite element software are described next.…”

Section: Materials Property Definitionsmentioning

confidence: 99%

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Final Shape of Precision Molded Optics: Part I—Computational Approach, Material Definitions and the Effect of Lens Shape

Ananthasayanam

Joseph

Joshi

et al. 2012

Journal of Thermal Stresses

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Coupled thermomechanical finite element models were developed in ABAQUS to simulate the precision glass lens molding process, including the stages of heating, soaking, pressing, cooling and release. The aim of the models was the prediction of the deviation of the final lens profile from that of the mold, which was accomplished to within one-half of a micron. The molding glass was modeled as viscoelastic in shear and volume using an n-term, prony series; temperature dependence of the material behavior was taken into account using the assumption of thermal rheological simplicity (TRS); structural relaxation as described by the Tool-Narayanaswamy-Moynihan (TNM)-model was used to account for temperature history dependent expansion and contraction, and the molds were modeled as elastic taking into account both mechanical and thermal strain. In Part I of this two-part series, the computational approach and material definitions are presented. Furthermore, in preparation for the sensitivity analysis presented in Part II, this study includes both a bi-convex lens and a steep meniscus lens, which reveals a fundamental difference in how the deviation evolves for these different lens geometries. This study, therefore, motivates the inclusion of both lens types in the validations and sensitivity analysis of Part II. It is shown that the deviation of the steep meniscus lens is more sensitive to the mechanical behavior of the glass, due to the strain response of the newly formed lens that occurs when the pressing force is removed.

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Section: Figurementioning

confidence: 99%

Section: Materials Property Definitionsmentioning

confidence: 99%

Final Shape of Precision Molded Optics: Part I—Computational Approach, Material Definitions and the Effect of Lens Shape

Ananthasayanam

Joseph

Joshi

et al. 2012

Journal of Thermal Stresses

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“…It is the viscoelasticity that gives rise to creeping phenomenon in the pressing and stress relaxation in the annealing stages. At a much higher temperature near SP, glass behaves like a viscous liquid (Chang et al, 2007;Yan et al, in press). Therefore, in order to determine the molding conditions to improve the quality of the molded lens, clarification of the viscoelasticity and viscosity of glass at a high temperature is very important.…”

Section: Introductionmentioning

confidence: 95%

Investigation on the viscoelasticity of optical glass in ultraprecision lens molding process

Zhou

Yan

Masuda

et al. 2009

Journal of Materials Processing Technology

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“…Magnetorheological finishing (MRF) and precision polishing are two automatic polishing methods that are commercially available. Due to the complexity of these processes and the long cycle times involved, the overall costs for medium-to high-volume productions of aspherical lenses are very high [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Transcription Characteristics of Mold Surface Topography in the Molding of Aspherical Glass Lenses

Cha¹,

Hwang²,

Kim³

et al. 2009

Journal of the Optical Society of Korea

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The transcription characteristics of the mold surface in the molding of aspherical glass lenses for camera phone modules have been investigated experimentally. The surface topographies of both the form and the roughness were compared between the mold and the molded lens. For the form topography, the molded lens showed a transcription ratio of 93.4% against the mold, which is obtained by comparing the form error (PV) values of the mold and the molded lens. The transcription characteristics of the roughness topography were ascertained by bearing ratio analysis.

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Simulation of an Aspheric Glass Lens Forming Behavior in Progressive GMP Process

Cited by 17 publications

References 1 publication

Final Shape of Precision Molded Optics: Part I—Computational Approach, Material Definitions and the Effect of Lens Shape

Final Shape of Precision Molded Optics: Part I—Computational Approach, Material Definitions and the Effect of Lens Shape

Investigation on the viscoelasticity of optical glass in ultraprecision lens molding process

Transcription Characteristics of Mold Surface Topography in the Molding of Aspherical Glass Lenses

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