Float glasss made by floating molten glass on top of molten tin. The primary advantage of this method is that it makes glass with a very flat surface and uniform thickness. Window glass and other types of flat glass have been made with the float process since it was developed in the 1950s. Float glass is typically made from soda-lime glass, although it can also be made from special materials such as borosilicates. 1 Fill a long, flat container with molten tin. This container is typically only 6cm deep but may be up to 50m long. Enclose the tin bath in a positive-pressure atmosphere of hydrogen and nitrogen.
2 Feed the molten glass onto the tin bath through a delivery canal. The glass will flow onto the molten tin surface and float on top of it. The glass surface will therefore remain completely smooth with an even thickness.
3Reduce the temperature of the glass gradually. The temperature will slowly lower from 1,100 degrees Celsius to approximately 600 degrees Celsius. At this point, the glass sheet is hard enough to be lifted out of the tin bath and onto rollers. 4 Control the thickness of the glass sheets. A faster roller speed will result in thinner glass and rollers will also adjust the width of the glass sheets.
5 Cool the glass sheets down to room temperature. The glass sheets will pass through a 100m-long kiln, where it will be gradually cooled. This will allow the glass to cool without cracking or experiencing unnecessary strain. Once the glass has cooled completely, it can be cut into sheets of the desired size.
Contact:novalglass Released time:2010-12-15 22:01:04