How Glass is Made – From Cutting to Low-e Coatings

Glass Fabrication,
Low-E Glass,
Making Glass,
Understanding Performance

In How Glass is Made, From the Batch House to the Lehr we covered how glass starts as a simple combination of sand, soda ash, limestone and dolomite, moves to the batch house, enters the furnace, and then goes through the melting, fining, forming, annealing, and cooling processes.

The next parts of the glass making process are focused on cutting and shipping. Once the glass has been cooled and prepped, it is cut by first scoring it with carbide cutting wheels. The process starts by snapping it over a roller that acts as a fulcrum. The main line scoring equipment consists of slit cutters, which score the glass in the direction of the flow and the cross cutters that score the glass across the flow. After scoring, the glass remains as a continuous ribbon that enters the main line where the cross cutter scores are opened.

The glass, now in plate form, proceeds from the main line to the packing lines. The glass is transferred to the packing lines by a corner table, which is a belt and roll conveyer combination. After leaving the corner table, the glass enters the snapping conveyers where slit scores are opened. After the snapping conveyors, the glass is transferred one section at a time on to narrow conveyers. Pieces of glass that do not pass inspection are recycled through the cullet system.

Next, the glass moves on the conveyor to an automatic vacuum transfer module (VTM) system. Working like a vacuum cleaner, the glass is sucked off of the main conveyer and placed on to a finished stack. As the stack gets higher, an elevator table indexes downward in order to maintain a consistent drop in the glass. Once complete, the elevator table is lowered and the completed rack is moved aside and replaced with an empty one.

The final step in the process involves placing the glass in the Magnetron Sputter Vacuum Deposition (MSVD) chamber where a low-e coating is applied to the glass. In this step, the glass is rolled into the vacuum chamber where microscopic minerals, mainly silver, are bonded on to the glass surface. A final quality inspection is performed and the glass is then stacked and wrapped, moved to shipping and sent out the door.

For more information about how glass is made or any other questions related to glass, please contact Vitro glass or call 1-855-VTRO-GLS (1-855-887-6457).