A Guide to the Aluminium Extrusion Process

Aluminium is one of the most versatile metals on planet Earth with a wide range of advantages that make it ideal for a range of applications across homes, as well as commercial and industrial sectors. One of the processes that aluminium can go through is called aluminium extrusion which is applied to items used in the construction of homes and buildings, most of which are not noticeable. The aluminium extrusion process is a highly efficient and versatile manufacturing method, for which LA Metals are expert suppliers, that allows for the creation of complex shapes and structures with minimal waste.

In this blog, we will help you to understand the specific process of aluminium extrusion and the benefits of using aluminium that has been created this way.

Two ways of performing aluminium extrusion

Wait, there is more than one way to perform the aluminium extrusion process? Indeed, there are two different ways this process can be carried out – direct and indirect – but before we can understand each process, we must outline the components that make up the process.

  • The Extrusion Die – This is what the aluminium will be pushed into to create the desired shape and design. It is typically round and preheated to extend the die’s life and ensure an even metal flow.
  • The Billet – The billet is a cylindrical block of aluminium that is pushed through into the die, that is also preheated to provide less friction.

Direct extrusion

The first method of aluminium extrusion is direct extrusion. This is the most common method where the die head is held in place and the aluminium billet is pushed through the die using a high-pressured ram.

Indirect extrusion

The other method of aluminium extrusion is indirect extrusion. During this process, the aluminium billet is held in place rather than the die to create the desired shape. There are some benefits of performing this method, including being able to press products with smaller cross-sections and keeping friction to a minimum.

The extrusion process

For the actual aluminium extrusion process, we’ll walk through the direct method as this is the most common method that most aluminium suppliers will use.

Step 1:

The first step in the extrusion process is to design the extrusion profile. This involves specifying the dimensions and shape of the profile, as well as any necessary features such as holes and slots. Once the design is complete, a die is created to produce the desired profile. The die is then preheated to 450 – 500°C which helps extend the die’s lifespan.

Step 2:

Next, the billet of aluminium is prepared which is typically made from an aluminium alloy. The billet must be able to be pliable and easily mouldable, therefore, it is also preheated just below aluminium’s melting point (660.3°C).

Step 3:

The billet is then loaded into the extrusion press, which consists of a container to hold the billet and a hydraulic ram to push it through the die. As the billet is pushed through the die, it takes on the shape of the extrusion profile and emerges from the press in a continuous length.

Step 4:

Once the profile has been extruded, it will begin to cool before being cut to the desired length. During this point in the process, any additional processing steps including welding, punching and bending may be completed if the profile is more complex in its design.

Step five

The final step involves finishing the aluminium profile with the desired look. This can involve many aluminium finishes, such as polishing, anodising or applying a powder coating, all of which add many more benefits to the aluminium product.

An easy way to visualise the process of aluminium extrusion is to think of it like pushing toothpaste out of a tube. The toothpaste exists the tube in the same shape as the hole. Another similar way to visualise the process is by pushing play-dough or clay through a shape maker. The pressure pushes the dough through a shaped hole to create a star, square or triangle shape, for example. Aluminium extrusion is virtually the same process, creating a desired shape for a variety of aluminium products and fittings.

The benefits of aluminium extrusion

The process of extruding aluminium has many advantages and benefits over other metals such as iron or steel. The main benefits of extruding aluminium include:

  • Lightweight – aluminium is extremely lightweight compared to metals such as iron, steel, brass or copper. Thanks to aluminium’s lightweight properties, it is easier to handle and transport and can be used for a wide range of industries such as aerospace and construction.
  • Strong and durable – Aluminium is extremely strong and can be used for the most demanding of applications that are situated in various environments, including cold environments where the metal becomes stronger.
  • Corrosive resistant – Aluminium doesn’t rust thanks to the protective oxide later on the surface which can be enhanced by several finishes including powder coating and anodising.
  • Cost-effective – Compared to aluminium casting, the aluminium extrusion process is relatively inexpensive and is widely used to form many products from this amazing metal.

Specialised aluminium extrusion suppliers

Here at LA Metals, we are one of the UK’s premier suppliers of aluminium extrusions, with a vast range of stock for an array of industries. We not only supply aluminium products including angles, tubes, box sections and more, but we also specialise in aluminium finishing including powder coating, anodising, polishing and fabrication.

If you’re looking for a bespoke aluminium design for us to extrude, then contact us today and speak to one of our expert team for all your information.