Modeling of drawing thin glass sheet from a preform

Abstract

A one-dimensional model of thin glass sheet drawing has been developed. This model includes momentum, heat and mass balance equations. The density, viscosity and specific heat of the glass were calculated as functions of temperature, and the glass emissivity was defined and calculated as a function of both temperature and glass thickness. After allowed simplifications, two ordinary differential equations were obtained and solved using the Runge Kutte method. The model was used to investigate the influence of different process parameters (the velocity of lowering the preform into the furnace, the axial temperature profile of the furnace, the drawing force and its direction, etc.) on the change in the shape of the drawn glass sheet for different glass compositions and various geometrical characteristics of the preform. A laboratory device for drawing glass sheets from rectangular preforms enabled full control of the process parameters, their measurement, as well as data acquisition. The results of the numerical simulation were compared with the experimental data and good agreement between them was found.