Parent Category: Industries

Simulation of Quartz Glass Sagging

The simulation of quartz glass sagging can perfectly be performed with our CFD software NOGRID points. Fused Silica (SiO2) is a synthetic molten, amorphous quartz glass. Quartz glass has an extraordinarily high optical transmissivity for ultraviolet light. Due to its low coefficient of thermal expansion, quartz glass can withstand very high operating temperatures. The very good UV-light transparency of quartz glass cannot be outperformed by any other industrial glass material. Quartz glass components and fused silica optics are made of large silica glass blocks, called quartz glass "boules". This raw fused quartz glass material can be sawn, ground, polished and shaped according to customers specifications.

Here we present a simulation, computed by our meshless CFD software NOGRID points, where a quartz glass cylinder is formed in an oven under its dead weight.

 CFD simulation sagging quartz glass

Figure 1: Simulation of the slumping a quartz glass cylinder, computed with NOGRID points

Quartz glass is most commonly heated in an oven and 'sagging' it over a form or into a mold. The glass is heated up slowly to avoid thermal shock. Approximately at the sagging temperature the quartz glass will begin to soften and appear glossy. Depending on the required process time sagging occurs at 100 °C to 300 °C above the sagging temperature. Once the quartz glass has sagged to the final state or the quartz glass has achieved the desired form the heat is quickly vented and the temperature is reduced to prevent further movement of the quartz glass and then it is stabilized at its respective annealing temperature and annealed.

It is also possible to simulate a forming process using different tools to accelerate the forming time.