All Title Author
Keywords Abstract


3D Modelling of Thermal Replication for Designing Progressive Glass Moulds

DOI: 10.4236/njgc.2013.31006, PP. 34-42

Keywords: Aspherical Lens, Finite Element Model, Precision Glass Forming, Thermal Replication, Metrology

Full-Text   Cite this paper   Add to My Lib

Abstract:

Worldwide, ESSILOR International provides customers with Progressive Addition Lenses (PAL), which replace bifocal lenses. Thermal replication is one process to produce glass moulds for PAL, using sagged glass on a ceramic slumping block. In this paper, thermal replication for producing PAL glass moulds is developed through 3D modelling and experimentation. Our numerical approach is validated by comparing it with experimentation on the global 3D topology of the sagged glass. It is also validated by using more severe optical comparison criteria, developed by ESSILOR International to analyze the conformity of their products. Through modelling, the thermal replication is analyzed by studying the evolving contact between the sagged glass and the ceramic slumping block during the thermal cycle and the glass flow on the upper side of the sagged glass.

References

[1]  H. M. Pollicove, “Survey of Present Lens Molding Techniques,” Proceedings of SPIE, Los Angeles, 11 January 1988, pp. 158-159.
[2]  L. Smith, R. J. Tillen and J. Winthrop, “New Directions in Aspherics: Glass and Plastic,” Proceedings of SPIE, Los Angeles, 11 January 1988, pp. 160-166.
[3]  M. Sellier, “Optimal Process Design in High-Precision Glass Forming,” International Journal of Forming Processes, Vol. 9, No. 1, 2006, pp. 61-78. doi:10.3166/ijfp.9.61-78
[4]  Y. Chen and A. Y. Yi, “Design and Fabrication of Free-form Glass Concentrating Mirrors Using a High Volume Thermal Slumping Process,” Solar Energy Materials and Solar Cells, Vol. 95, No. 7, 2011, pp. 1654-1664. doi:10.1016/j.solmat.2011.01.024
[5]  D. R. Gunasegaram, I. M. Bidhendi and J. M. McCaffrey, “Modellling of the Casting Process of Plastic Ophthalmic Lenses,” International Journal of Machine Tools and Manufacture, Vol. 40, No. 5, 2000, pp. 623-639. doi:10.1016/S0890-6955(99)00097-8
[6]  T. S. Kwak, T. Suzuki, W. B. Bae, Y. Uhehara and H. Ohmori, “Application of Neural Network and Computer Simulation to Improve Surface Profile of Injection Molding Optic Lens,” Journal of Materials Process Technology, Vol. 170, No. 1-2, 2005, pp. 24-31. doi:10.1016/j.jmatprotec.2005.04.099
[7]  Y. M. Stokes, “Creeping-Flow Computational Modelling of Optical Quality Free-Surfaces Formed by Slumping of Molten Glass,” In: B. J. Noye, M. D. Teubner and A. W. Gill, Eds., Proceedings of Computational Techniques and Applications: CTAC97, World Scientific, Singapore City, 1998, pp. 671-678.
[8]  Y. M. Stokes, “Thermal Replication: A Comparison of Numerical and Experimental Results,” In: E. O. Tuck and J. A. K. Stott, Eds., Proceedings of the 3rd Biennial Engineering Mathematics and Applications Conference: EMAC98, Institution of Engineers, Adelaide, 1998, pp. 471-474.
[9]  Y. M. Stokes, “Numerical Design Tools for Thermal Replication of Optical Surfaces,” Computers & Fluids, Vol. 29, No. 4, 2000, pp. 401-414. doi:10.1016/S0045-7930(99)00030-4
[10]  Y. Agnon and Y. M. Stokes, “An Inverse Modelling Technique for Glass Forming by Gravity Sagging,” European Journal of Mechanics-B/Fluids, Vol. 24, No. 3, 2005, pp. 275-287. doi:10.1016/j.euromechflu.2004.10.002
[11]  G. C. Firestone, A. Jain and A. Y. Yi, “A Precision Laboratory Apparatus for High Temperature Compression Molding of Glass Lenses,” Review of Scientific Instruments, Vol. 76, No. 6, 2005, Article ID: 063101-063108. doi:10.1063/1.1921367
[12]  A. Y. Yi and A. Jain, “Compression Modelling of Aspherical Glass Lenses. A Combined Experimental and Numerical Analysis,” Journal of the American Ceramic Society, Vol. 88, No. 3, 2005, pp. 579-586. doi:10.1111/j.1551-2916.2005.00137.x
[13]  A. Y. Yi and A. Jain, “Numerical Modelling of Viscoelastic Stress Relaxation during Glass Forming Process,” Journal of the American Ceramic Society, Vol. 88, No. 3, 2005, pp. 530-535.
[14]  D. Lochegnies, P. Moreau, F.Hanriot, N. Navarudiger and P. Hugonneaux, “Experimentation and Modelling of Thermal Replication for the Design of 2D1/2 Aspherical Glass Components,” Journal of Glass Science and Technology, Vol. 51, No. 3, 2010, pp. 130-137.
[15]  J. M. Cox and M. G. Gee, “Hot Friction Testing of Ceramics,” Wear, Vol. 203-204, 1997, pp. 404-417. doi:10.1016/S0043-1648(96)07459-5

Full-Text

comments powered by Disqus