How is flat glass produced?
Most glass today is produced by the float process. The raw materials (primarily silica sand, soda ash, and limestone) are weighed, mixed and conveyed to a melting furnace. Coloring agents may be added to produce tints, such as green, blue, bronze, or grey. Molten glass flows continuously from the furnace onto a bath of molten tin where a continuous “ribbon” is formed. The glass floats on the tin and is pulled and stretched to the desired thickness and gradually cooled until it starts to solidify. The glass ribbon is then lifted out of the tin bath onto rollers and conveyed through an annealing lehr where the glass is slowly cooled until the glass exits the lehr at slightly above room temperature. At this point, the glass is flat and has virtually parallel surfaces. The continuous ribbon is then cut to size, packaged, and shipped to the customer for further processing.
