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

✍ Scribed by Tianfeng Zhou; Jiwang Yan; Jun Masuda; Tsunemoto Kuriyagawa

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 590 KB
• Volume: 209
• Category: Article
• ISSN: 0924-0136
• DOI: 10.1016/j.jmatprotec.2008.10.030

✦ Synopsis

Glass molding press is an efficient manufacturing technology for ultraprecision optical elements with complex shapes. In glass molding, viscoelastic property of glass is an essential aspect that determines the glass deformation behavior around the molding temperature. In this paper, viscoelasticity of glass has been measured experimentally by uniaxially compressing cylindrical glass preforms above the glass transition temperature using an ultraprecision glass molding machine. The elastic modulus and viscosity of glass were obtained by curve fitting techniques using the Burgers model and the Maxwell model for creep and stress relaxation, respectively. Based on the thermo mechanical and viscoelastic parameters obtained from experiments, finite element model simulations of the glass molding process were performed, which can be used to visualize the stress/strain distribution and to predict the residual stress in glass.