Almost all flat glass manufactured today is done so through a float bath process.
In this process molten glass is moved out of a furnace and floated on the surface of a bath of molten tin. The glass sheet slowly cools as it moves along the bath within a controlled atmosphere.
Once the sheet of glass is sufficiently hard it is moved off the bath and passed through an annealing furnace to remove residual stresses.
Thick walled pieces of glass may be hot pressed. In this process a molten slug of glass is placed between two mould surfaces and the glass is clamped into the desired shape.
Sheet glass may also be formed through a rolling process whereby the molten glass is passed between two circulating rollers. This process does not produce the high quality of the molten bath process.
The formation of glass bottles and containers is usually achieved through a blow moulding process where the glass is placed in a mould and forced to conform to the mould walls under high air pressure.