Capalex Aluminium Extrusions
Aluminium Extrusions
Capalex Aluminium Extrusions

Glossary Of Terms


Either done naturally, resulting in a change in properties of an alloy occurring slowly at room temperature, or can be done using elevated temperatures (artificial aging) which results in increased strength and hardness using a heating oven.


A metal composed of one or more element, in aluminium, it is aluminium but includes one or more other elements.


Soft lightweight metal with a dull silvery appearance. It is known for its lightweight, excellent strength, high thermal conductivity, high reflectivity and corrosion resistance.


Anodising is an electro-chemical process, which physically alters the surface of the metal to produce a tough oxide layer on the surface.


Aluminium alloy usually in a cylindrical form, used in the extrusion press to produce the extrusion.


Burrs created during the sawing and machining processes can be removed, if necessary, to produce a cleanly finished component.


These can be hollow or flat, and create the shape of the extrusion by heated aluminium being forced through.

Die Line

Indent lines which are present in extruded material, usually caused by roughening of the die bearing.

Die Number

A number assigned to each die to recognise it.

Direct Extrusion

A preheated billet is pushed through the die by ram pressure. The direction of the metal flow is in the same direction as the ram travel.


Process of preparing the metal by making a rough surface usually before painting or anodising is carried out.


Forcing the aluminium billet through a die by pressure.


Based on engineering drawings, the raw metal is converted into specified component parts, can involve one or more of the following processes; sawing, CNC machining and milling, punching, conventional drilling, tapping milling and turning, deburring.

Heat Treating

Heat treatment is often used to improve the aluminium's strength and hardness.

Indirect Extrusion

With Indirect extrusion the die located at the front end of a hollow stem moves relative to the container. The die is either pushed through the container or the container is pushed over the die.

Mill Finish

Mill finish is the dull silvery finish obtained after the metal has been extruded without any further surface treatment to the metal.


When aluminium is polished it will remove any blemishes such as die lines and scratches, producing a mirror like finish.

Powder Coating

Powder coating is an advanced method of providing a decorative and protective finishing to metals and a range of other materials, something similar to paint spraying.