Can you explain the aluminium extrusion process in simple terms?

Aluminium extrusion is a metal forming process used to transform lengths of aluminium alloy into objects with a particular cross-section. The aluminium lengths, called billets, are pushed through an extrusion die with a smaller cross sectional area than the billets themselves. The billets take on the shape of the cross section on the die, so they can be used in various applications. The aluminium extrusion process is a relatively quick, simple and cost-effective one, and aluminium is particularly suited to this kind of forming.