The aluminum starts in a billet.
Billets are 500kg aluminum pieces of metal, usually in the shape of a cylinder.
A die is made to shape the aluminum.
A die is manufactured. The aluminum is heated to about 660 degrees Centigrade. The hot aluminum billet is forced through the die into the desired shape. This aluminum is now extruded into 20 foot to 24 foot lengths. The extrusion shape can be as sophisticated as required. Below is an illustration of the billet, the die and the resulting extrusion.
The extrusion is still hot.
The extruded aluminum rolls onto a conveyor system, where it cools. It is then stretched a few inches to it's full length.
Extruded aluminum is used in window casing, aircraft molding, the interior of vehicles, and of course in our acoustic panels.
Here are a few examples of aluminum extrusion.
Finishing on extrusions.
The finish on the extrusions can be the standard mill finish, which is what comes out of the die be default. the metal can be anodized different colours.
Here is a short video on the extrusion process.