From the sand to the glass
To see how they manufacture glass, we have come to the Guardian of Laudio. 700 people work here and produce 600 tons of glass every day.
The process starts in the waste bins. In fact, 75% of the glass is silica sand. This sand that arrives in trucks is the glass that will later become the windows of houses or cars.
Along with the silica residue, the glass also contains other components, mainly limestone and sodium carbonate or soda.
The sand is mixed and sent from the warehouses to the production plant through fully automated vials.
In the factory, the sand enters the oven. It's really hot in here. Not surprisingly, the formation of the glass requires the melting of the sand by heating the furnace to 1,500°C.
The activity of this oven is continuous: 365 days a year and 24 hours a day. In August he will be working for 14 years, during which time he has not stayed for a single day. It has already produced almost 3 million tons of glass.
The sand, once melted, flows into a large swimming pool.
ITZIAR SUBARTE; Guardian Llodio: Beira eztainuzko igerileku batera botatzen da, eta horrela flotatu egiten du dentsitate-diferentziagatik. That's how we get the glass out. Imagine the following: we're 14 years without breaking the glass.
The relationship between the surface tensions of molten glass and tin produces an infinite sheet of glass, a sheet of glass that is continuously stretched.
The thickness and dimensions of the glass are set here. In fact, at 1100°C, glass is like chewing gum: it can stretch and shrink.
The whole process is automated: from the control room the temperature and pressures are monitored, as well as the gas consumption of the oven.
The glass is separated from the tin, cooled and extracted at 600°C. It's already solid. The temperature sensors control the cooling turbines and work automatically so that the glass does not give problems when it is subsequently cut.
ITZIAR SUBARTE; Guardian Llodio: If the glass does not cool down gradually, what happens? Well, the glass breaks and then we don't have sheets and we don't have production. In order not to break the glass, we have to control it.
when it is at 80°C, the glass is marked and cut. The glass is marked with a pseudo-label: tungsten carbon. What has been an endless sheet of glass so far, is divided here into several parts.
The laser continuously monitors the glass; if a defect is detected, it is displayed on the screen by means of a color code according to the type of defect. The defective parts are separated and recycled back into the oven.
The marks left on the corners by the oven wheels are also removed.
Finally, the glass sheets are ready for storage. The stacking work is usually done by robots, but when making glass pieces of smaller size, for example today, this work needs to be done manually.
The glass is neatly stacked and ready to be distributed in trucks. What a few minutes ago was a pile of sand has turned into bright glass that will be a window and/or a mirror in any house or car.
Buletina
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