There are a number of different things that happen at a glass factory. Most glass factories either make sheet glass or pressed or blown glass, which can be molded into a variety of different shapes. Each of these types of factories will turn silica into glass by heating it and mixing it with a few other materials, including an alkaloid and a stabilizer, and then cooling it until it solidifies. A glass factory may also work with finished pieces of glass, etching or carving designs onto the surface.
The first thing that happens in any glass factory that creates glass out of raw materials is that these materials are measured and combined. Glass is made primarily from silica, which is a material found naturally in stone and sand. Other ingredients are added to the silica to allow it to melt more easily, change color, or resist breaking and cracking. In some factories, the materials will be mixed by hand, though large scale production facilities will usually employ machines to mix the materials.
After the materials are mixed in a glass factory, they are heated until they melt. Molten glass can be shaped and worked into a variety of different products including bowls, cups, and window panes. Though glass is technically a liquid at room temperature, it's viscosity approaches infinity, meaning that it is not really possible to shape glass without heating it. In many cases, glass is heated to temperatures of around 2,700 degrees Fahrenheit (1,500 degrees Celsius), though some glass is workable at lower temperatures.
Once the glass is molten, a glass factory will shape it into a useable glass product. To make sheets of glass, the molten glass is poured onto a pool of molten tin, a metal that melts at a temperature much lower than the temperature of the molten glass. Floating on a pool of metal allows the glass to form into a very flat sheet. Alternatively, molten glass can be blown into bowls or glasses or pressed into heated molds that are allowed to cool along with the glass.
Though the process of glassmaking ends with shaping in many factories, some will also carve or etch cooled glass products. These processes involve special machines that are designed to manipulate glass without cracking or otherwise damaging it. A glass factory may specialize in this type of work or it may participate in all the steps of the glassmaking process.
