Have you ever thought how we get hollow profiles by extrusion? What kind of die is used? How do they create a hollow profile? Well, here we explain briefly the different parts of a die and how these profiles are created. We can start by remembering what a die is and what is for. If you get lost, maybe you should review aluminium extrusion process.

The die is a kind of opening disk that corresponds with the transversal section of the profile we want to get. In this process hot aluminium is pressed through the die. These elements are made of high temperature resistant steel, and its openings are made by electro-erosion.

Parts of a die

Die shoe: This element holds the dies and attaches them to the extrusion system.

Die: If the profile has to be solid we use a die with the same opening of the transversal section of the desired profile. In case that the profile had hollow parts, it is necessary to have 2 dies inside the die shoe:

Bridge die: It is responsible for making the hollow in the profile. It has openings that allow the aluminium to flow but force it to adopt the hollow shape through the mandrel, which is the cylinder we see in the image.

Cap section: Through it we give the desired external shape to the profile, while the bridge die gives the internal shape.

Collar: This element ends the die system and it is in charge of holding the pressures from the extrusion press.

Of course this description is a simplification to understand how hollow profiles by extrusions are made. When it comes to design, these elements acquire a great complexity depending on the required profile.

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