#AskGlaston Episode 8: How to control the glass flatness?

Thanks again for your interesting questions. This latest #AskGlaston episode will cover three of your questions:

1. Is it necessary to install an IR scanner at the furnace exit to monitor the glass exit temperature?
2. Is an exit temperature of 630–640 °C for all thicknesses too high?
3. Is it easier to control glass flatness in the heating or cooling section? Some specialists recommend controlling the flatness only during the quenching process. Also, is it true that we should control glass to bow upwards in a U-shape to avoid collisions with the rollers?

Watch our video answers here.

Is it necessary to install an IR scanner at the furnace exit to monitor the glass exit temperature?

We recommend a scanner for all our furnaces

Is an exit temperature of 630–640 °C for all thicknesses too high?

A temperature of 630–640 °C is generally too high for thick glasses of over 10 mm and too low for thin glasses below 4 mm. For average 6–8 mm-thick glass, this range is good.

Is it easier to control glass flatness in the heating or cooling section?

You should control glass flatness in both sections – heating and cooling. But the overall bow is controlled in the chiller. If you have a mechanical problem with the edges, then it’s recommended to bow the glass upwards. To avoid white haze, you should bow the glass downwards.

I hope you’ll get some practical advice again to share with your colleagues.

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About the author

Miikael Leskinen

Open-minded software artist who wishes tomorrow was already here today. Humanist and engineer in a messy package who loves new technology an possibilities that come from it. Applied and got into an art school but decided to become a reckless and free engineer in glass industry instead of serious and boring artist. Shameless tabletop drummer with angry Spotify playlist to annoy coworkers.