Aluminium Extrusion
Aluminium extrusion is a manufacturing technique whereby aluminium alloy is transformed into
objects with a cross-sectional profile for a wide range of uses. Aluminium alloys used for extrusions
include: 6060, 6063, 6063A, 6463, 6005A and 6082.
Aluminium’s unique combination of physical characteristics make it the ideal metal for extrusion; its
malleability allows it to be easily machined and cast. Aluminium is one third the density and
stiffness of steel so the resulting extruded products offer strength and stability, particularly when
alloyed with other metals.
Aluminium extrusion process
The process begins with designing and shaping the die to the appropriate shape. A cylindrical billet
of aluminium alloy is then heated to 350–500 °C (650–900 °F). The aluminium billet is then
transferred to a loader and a lubricant is applied to prevent it from sticking to the extrusion
machine.
The aluminium billet is forced through the die with substantial pressure using a ram.
To avoid the formation of oxides, nitrogen in gaseous or liquid form is added and allowed to flow
through the sections of the die. This results in an inert atmosphere and increases the life of the die.
Cooling and cutting
The extruded aluminium then passes on to a run-out table as an elongated piece that has formed
in to the shape of the die opening. It then goes to the cooling table where fans cool the aluminium
extrusion. Once cooled, the extruded aluminium is moved to another area for straightening and
work hardening. The hardened extrusions are then cut according to the required lengths.
Finishing
The final step in the process is to treat the extrusions with heat, which hardens the aluminium by
speeding up the aging process. Additional steps may be applied during this process to customize
the extruded parts further. This might include creating hollow sections, pins or piercings. Lastly,
colour, texture and brightness might be used for the aluminium’s finish. This includes aluminium
anodizing or painting.
Applications
Examples of products that require aluminium extrusions include tracks, aerospace engineering
products, frames, leisure & sporting goods, rails and heat sinks. From