Aluminium extrusion process starts with loading dies into extrusion machine. Die carries the shape of the profile which should be appeared in the final product. These dies are preheated to avoid any kind of thermal shocks during the extrusion process. We use Aluminum billet as feeding material and it has a shape of cylinder.
In the first step these billets are heated up to 900 F. Remember in your mind these temperature only soften the aluminum cylinder. Either shape or the color of the cylinder will not change during this process. Pressure is first applied and billet squeeze through the die. We can have the expected profile from other side of the die and it is cooled either by air of water. After this all the profiles are collected to a cooling table and carry on the cutting process of these profiles to a commercial lengths.
Now the most important process is aging where all the mechanical properties will introduce to these profiles. This process is known as "Age hardening". This is done in aging ovens. During this process some mechanical properties like yeild strength, elasticity, hardness can be optimized.