What is Aluminium Extrusion?

Aluminium extrusions are made from aluminium that has been pushed through a die of a specific shape or profile, resulting in a continuous cross-sectional piece. This is known as the aluminium extrusion process. It allows for various shapes and sizes to be created, ranging from simple flat bars to complex multi-void profiles.

Aluminium extrusion is popular thanks to its favourable properties and multiple benefits, such as its light weight, strength, corrosion resistance and conductivity, combined with the aluminium extrusion process’s ability to create complex and integrated shapes. These benefits make aluminium extrusions ideal for use in numerous industries for various applications, including aerospace, automotive, electronics, construction and more.

At LA Metals, we are UK-leading aluminium extrusion suppliers with profiles in assorted dimensions and can even cut to size custom aluminium extrusion profiles. Check out the UK’s greatest aluminium extrusion range.

The Basics of Aluminium Extrusions

The basics of aluminium extrusions involve understanding the materials, the benefits, the applications as well as the process. Here is a breakdown of the factors involved.

Material – Aluminium Alloy

Aluminium alloys are chosen based on the required properties such as strength, ductility, corrosion resistance and workability. The alloy composition can include elements like silicon, magnesium and zinc to improve the properties and typically will be based on alloys 6061, 6063 and 7075.

Basic Benefits

The benefits of working with aluminium extrusions are many and include design flexibility to create complex shapes and additional bespoke profiles. Its lightweight yet strong properties make it ideal for applications where support is required, and heavy materials would be a hindrance. It also has great thermal connectivity, is cost-effective and sustainable and offers a stylish finish.

Applications

Aluminium extrusions are everywhere you look, from architecture to transportation, electronics to consumer products, industrial machinery, infrastructure, construction, energy and more. You can find it in solar panels and window frames, exercise equipment, structural components, marine fittings, conveyor systems, wind turbines and supporting bridges and rails.

The Six Steps of Aluminium Extrusion

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 and is also preheated to provide less friction.

Direct Extrusion

The first method 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-pressure ram.

Indirect Extrusion

The other method 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 process can be outlined in six primary steps, from the initial design phase to the final finishing treatments.

  1. Design and Creation of the Die

The first step is designing and creating the die, which is a steel tool used to shape the aluminium. The die is then preheated to 450 – 500°C.

  1. Billets Preparation

    Aluminium alloy is cast into long, cylindrical shapes known as billets. These billets are cut and heated just below aluminium’s melting point (660.3°C) to make them malleable but not molten.

    1. Extrusion Process

    The heated billet is then pushed through the die by a hydraulic ram. As it passes through, it takes on the cross-sectional shape of the die.

    1. Cooling

    The profiles are then cooled using water or air to help solidify the aluminium into its new shape.

    1. Stretching

    The extruded aluminium is then stretched while still soft to straighten it and relieve internal pressures from the cooling process.

    1. Cutting and Finishing

    The long aluminium extrusions are then cut to length and can be finished with anodising, painting, powder coating or polishing if desired.

    Methods of Joining Aluminium Extrusions

    So, how do you connect two aluminium extrusions together? Well, that depends on the type of extrusion. There are a few time-tested methods of joining extrusions. Albeit different, each of these methods can be helpful in future projects with bespoke aluminium extrusions, where stability and timesaving are key factors.

    1. Welding

    This is for a more permanent design. Welding requires the use of high heat, so safety is of the utmost importance. In jobs that require welding, an aluminium equal angle is often used, as it is simple to weld and shape. It forms a 90-degree angle and is commonly used in construction and ventilation systems.

    1. Mechanical Fastening:

    Chances are you’ve used the following method. The tightening of screws, bolts and rivets is the most common form of joining together two extrusions. It’s featured in the assembly of household items right the way through to the largest of industrial jobs.

    1. Adhesive Bonding:

    The practice of adhesive bonding follows the same principles. It’s one of the easier forms of joining extrusions as there’s no professional assistance required, but you should still take caution when using adhesives of any kind and ensure the bonding is sturdy enough for the project.

    1. T-Slot Connections:

    Aluminium tee sections are made with joining in mind. T-slot connections help join the extrusions at a right angle. They’re considered lightweight yet sturdy and are used in equipment frames and mounting systems.

    1. Threaded Inserts:

    These are small adapters that allow you to screw into a threaded hole in aluminium extrusions. They’re perfect for joining two or more objects and creating strong connections in aluminium structures. Threaded inserts are featured in furniture items and provide easy assembly and disassembly.

    How Do You Attach Things to Aluminium Extrusions?

    Clamp-On Mounting: Requires no drilling. To attach, open the clamp and adjust it to be fitted before tightening it into place.

    1. T-Slot Fastening:

    Position the aluminium extrusions with the T-slots facing towards the area you want to connect. Insert the bolts and proceed to tighten them.

    1. Adhesive Bonding:

    Simply apply adhesive on the surface and carefully align the extrusions to join them together. Be careful and follow all the instructions regarding use of the adhesive.

    Shop Aluminium Extrusions at LA Metals

    Now you know the answer to what is aluminium extrusion, the next question you need answering is where to get them. LA Metals is a trusted supplier and offers a wide array of services. Everything from anodising to fabrication can be provided bespoke to your specifications. Contact our experienced team for more details and we can work with you to provide all the aluminium services you need.