That die then enters the extrusion press. An oven heats a round bar of aluminium – or magnesium – to several hundred degrees Celsius. As soon as the material is soft enough, it is ready to be pressed through the mould. This happens under high pressure. At the other end of the mould the aluminium comes out in the shape of the die. The aluminium is then cooled and – as soon as all of it has been pressed through the die – straightened. After that, it is swan and, if necessary, treated further.
See the animation for more information.