3D Modelling of Thermal Replication for Designing Progressive Glass Moulds

Dominique Lochegnies, Philippe Moreau, Fabienne Hanriot, Patrick Hugonneaux

ESSILOR International, Saint- Maur-des Fosses, Paris, France.
ESSILOR International, Saint- Maur-des Fosses, Paris, France..
Pole de Recherches et d’Enseignement Supérieur, Université Lille Nord de France, Lille, France.

DOI: 10.4236/njgc.2013.31006                

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.

Keywords

Aspherical Lens; Finite Element Model; Precision Glass Forming; Thermal Replication; Metrology

Conflicts of Interest

The authors declare no conflicts of interest.

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