| Glass manufacturing Illustration |
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Preparing mixturesGlass is formed by the fusion at more than 1,300° C of a mixture of sand, soda ash, limestone and cullet (broken glass). Sand is the basic raw material that goes into glass making. To give an example, the French production site of Arc International consumes an average of 1,000 tonnes of sand per day.Glass manufacturing There are three technical processes: pressing, blowing and centrifuging. Pressed glass :Pressed glass manufacturing is suitable for items with thick edges such as stemware or beer mugs.The glass drop is deposited in a mould which shapes the outer form of the product before a central plunger stamps out its inner volume. Blown glass :Before being placed in the mould the drop of glass is stamped by the central plunger. The blank shape is put into the finishing mould and then blown to give it its final appearance. This process is particularly suitable for delicate items with thin walls and curved stems Centrifuged glass :Centrifuged glass is used for making dishes or plates. The drop of melting glass falls into a mould which is then rotated rapidly to spread it uniformly in the mould. AnnealingIn order to make a glass perfectly solid, it undergoes a final manufacturing stage known as annealing. The glass is then heated then cooled slowly in a homogenous way. This process avoids tension between the inside and the edge of the item. DecorationSome items may also be decorated. A lot of decorative processes are done automatically, however, some particularly special decorating always has to be done manually. PackagingThe packaging operation is automated for finished products. Some of the unfinished products which still have to be decorated are packed manually. This type of bulk packaging makes it easier to transport or store products |