Extrusion is the process of shaping aluminium by forcing it through a shape opening in a die. The resulting aluminium extrusion usually has the same profile as the die opening. The extrusion process features different steps to aid in the making of the final product.
These steps and processes include:
- The design of the profile required is discussed and created depending on requirements and technical capability.
- The shape and design of the die is then created.
- A cylindrical billet of aluminium alloy is heated and transferred to a loader where a lubricant is added to keep the heated billet from adhering to the ram or die.
- Pressure is applied using a ram which pushes the heated billet into a container which then forces it through the die opening.
- Nitrogen gas or liquid is allowed to flow through the opening of the die to prevent oxides of aluminium from forming.
- The newly extruded section is then passed onto a run out table. It is important to specify visible surface during design in order to protect this surface from the runners on the run out table.
- The extruded aluminium is placed on the cooling table where it is either cooled by fans or by liquid.
- The hardened material is then heat treated in an ageing oven and cut to size.
- If required the aluminium etrusion can then be either painted or anodised.
For further customisation, there are other processes that can be added to the basic extrusion process. Some of the custom extruded parts that require further processing include hollow sections, piercing mandrels or pins. The colour, texture and brightness of the finish can also be adjusted after the extrusion process.