What is Aluminum Extrusion Profile ?
Sunday, December 23rd, 2007Aluminium extrusions are made from solid aluminium cylinders called aluminum billets, which are continuously cast from molten aluminium. Billets are available in a wide variety of alloys, pretreatments and dimensions, depending upon the requirements of the manufacturer. The extrusion process involves aluminium metal being forced through a die with a shaped opening.The extrusion process involves aluminium metal being forced through a die with a shaped opening.
This is made possible by preheating the billet to 450-500 C and then applying a pressure of between 500 and 700 MPa (equivalent to the pressure found at the bottom of a 60km high water tank!). The heated and softened metal is forced against the container walls and the die by a hydraulic ram, the only exit is the geometric cross-section of the die opening, and the metal is squeezed out.
The extrusion leaves the die at a temperature of around 500??C and the exit temperature is carefully controlled in order to achieve specified mechanical properties, a high quality surface finish and good productivity.
The Press
The press supplies the force necessary to squeeze the billet through the extrusion die. It consists of:
- The container where the billet is put under pressure.
- The main cylinder with the ram for pushing the billet into the container and through the die.
- The front platen giving counter support to the die package.
- The main columns fixing the front platen and the cylinder together.
The die is supported by a series of back dies or backers and bolsters for transferring the main press load to the front platen.
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