GLASS TEMPERING

At BGGT we have a “Glaston FC500” tempering oven that produces some of the flattest glass in the industry. With the “I look” laser scanner attached, each piece of glass is scanned to ensure the highest quality specifications are met.

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Tempered glass is Annealed Glass that is strengthened through the process of heating and cooling the surface rapidly. This process creates surface compression and tensile strength that causes glass to be more resistant to breakage yet allows it to disintegrate into small pieces if a break occurs. Tempered glass reduces thermal stress in the glass and is approximately five times more impact resistant than non-tempered glass. The tempering process is a safety requirement that is mandatory in most design specifications and building codes.

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Manufacturing Process:

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In the tempering and heat strengthening process the glass reaches approximately 600° C - 680° C as it oscillates back and forth within the furnace. This combination of heat and movement maintains and creates the flat glass surface. From the furnace the glass is subject to an immediate application of rapid cooling with the use of high-pressure air (quench and or cooling section). In the quench, it is critical to sustain the quench for long enough to prevent any re-heating of the glass surfaces from the still hot glass core, and to extract heat uniformly from both surfaces of the glass. Uneven heat extraction can produce quality issues such as bow or warp.  While in the quench, the glass again becomes stable as it cools rapidly from 680° C to approximately 40° C. The cycle time or run time for a manufacturing cycle is dependent on thickness of glass and the manufacturing equipment being used.