Before extrusion begins, the die is also heated in a furnace. The die is a steel disk containing one or more cavities through which the aluminium is extruded. The die assembly is lowered into a holder and transferred into position within the press.

The aluminium billets are heated in order to make them soft and then sawn to the required length. Before entering the press, the rear face is sprayed with a release agent to prevent it from sticking to the ram.

Note that the billets are often heated so that the front end is hotter than the rear (taper heating). This is because as the billet progressively deforms in the press, it also heats up due to friction and deformation.

Once inside the press, the billet is initially compressed and expands outwards to fill the container. Any trapped air is released by withdrawing the container/billet from the die face.

The main extrusion cycle begins and as the profile emerges, it is cooled using air or water sprays in order to develop its metallurgical properties. At the end of extrusion, there is still a small length of billet remaining. This ‘butt end’ is sheared off in order to present a flat face for the subsequent billet to join onto.

The extrusion is sawn off just past the cooling zone and then transferred to the stretcher. A small stretch is applied in order to remove any distortions and straighten the profile. This is then sawn to the final length.

Finally, the profiles are stacked and may then go on for further processing, such as painting, anodizing or ageing, in order to produce the required surface finish, mechanical properties and corrosion resistance.

This animation was developed and released by Sapa AB and Materials e-Learning Technologies under a Creative Commons Attribution-ShareAlike 3.0 unported iicense.

joshmnky
2013-05-09T00:18:53.000Z
How would the product differ if you heated the aluminum to a liquid and pushed it through with air pressure? Seems like it would work if the material cooled to a solid on its way through the die.

corematerials
2013-03-15T21:09:37.000Z
Extrusions rarely emerge from the die perfectly straight, so a stretch is required to achieve this.

kuku196
2013-03-03T21:35:45.000Z
Freaking hard to reword this !

Sandeep Godara
2013-01-15T09:21:14.000Z
why we do extrusion stretching….?

Aphichon Vongburee
2012-12-16T16:55:34.000Z
“Thank you so much”

corematerials
2012-11-24T17:20:19.000Z
Thanks. We hope one day to do an interactive version – a virtual aluminium extrusion plant

Angelo Donofrio
2012-11-12T18:05:35.000Z
this is great. 1.5mins teaches me more than a 30minute lecture in university.



Andy Green
2012-11-01T15:33:32.000Z
Thanks a lot. Yep, there’s a bit more to it than squeezing toothpaste out of the tube

FurnaceRepairToronto
2012-10-24T01:32:11.000Z
Very informative. Had never seen the process before. It all seems straight forward but I know that a lot goes into the entire process.

Sureshmane Mane
2012-09-28T16:20:05.000Z
Gr8 job of demystifying Technology.

corematerials
2012-05-26T11:54:25.000Z
Thanks very much – glad it’s been helpful.

corematerials
2012-03-01T13:07:37.000Z
thank you very much. The CORE-Materials team

hasa310
2012-02-13T12:00:21.000Z
it is amazing !

JohnsonGetDown
2012-01-19T10:31:57.000Z
very nice!