The Different Types of Glasses Available for Human Use

Manufacturing Process of Glass

The manufacturing process of glass consists of 5 steps, which are as follows:

Raw Material Batching

The primary raw materials, which include silica sand, soda, calcium oxide, and magnesium, are weighed and blended into batches to which recycled glass (cullet) is added. The usage of ‘cullet’ minimises energy consumption. Machines test and sort the raw materials for eventual blending.

Melting of Raw Materials in the Furnace

From a mixing silo, the batched raw materials are transferred to a five-chambered furnace and melted. The furnace can achieve temperatures of up to 1600°C.

Drawing the Molten Glass onto the Tin Bath

At around 1000 degrees Celsius, liquid glass runs over a sprout and floats over the surface of a small pool of molten tin. Because the glass is quite viscous at this point, it does not react with the liquid tin, resulting in a flat glass ribbon. The spread speed determines the thickness of this ribbon while edge rollers maintain their breadth. The glass ribbon then exits the float tank at 600 degrees Celsius. Through this method, manufacturers can create ribbon thicknesses ranging from 1.9mm to 19mm.

Cooling of the Molten Glass in the Annealing Chamber

After leaving the bath of molten tin, the glass is cool enough to enter an annealing chamber known as a lehr. Here, the temperature of the glass gradually decreases to 250 degrees. This is done because the cooling process creates significant strains in the glass sheet that may cause it to crack beneath a cutter.

Quality checks, Automated Cutting, and Storage

Once the glass cools, it is subjected to stringent quality tests. Then, large machines slice the glass into sheets of sizes ranging up to 6000mm x 3660mm.

Classification of Glass

In general, glass is classified into two types: natural glass and manufactured glass. Natural glass is formed by natural processes. In fact, volcanic eruptions are responsible for the formation of natural glass. Tektites (meteorite impact) and fulgurites are two further types of natural glassware (lightning impact). On the other hand, melting numerous raw materials together makes manufactured glass. Silicate glasses are a good example of manufactured glass.

Types of Glass

Flat Glass

Windows and glass doors are examples of flat glass. It is the fundamental initial output of the glass-making via the float process. It has a consistent thickness and serves as the foundation for more sophisticated varieties of glass through subsequent processing. This glass breaks into lengthy fragments and is widely used in double-glazing after additional treatment.

Toughened Glass

Francois Barthelemy Alfred Royer de la Bastie, a Frenchman, patented toughened glass in 1874. This type of glass has the advantage of being significantly more resistant to breakage. Because the cooling process of toughened glass provides counteracting forces, if it does break, it will shatter into small, square fragments rather than shards, thus, reducing the chance of harm.

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