Finishing
Aluminium Extrusion
Aluminum extrusion is an advanced manufacturing technique for achieving uniform detailed parts with an indefinite length.
It is a production method in which aluminum is pushed under pressure through a die with the desired shape. The material can be extruded into complex shapes. There are several extrusion methods available in which shape complexity, surface quality, porosity, tolerances, and desired length playing an important role.
Finishing
Advantages
- Complex cross-sectional shapes are possible.
- Products receive an excellent surface finish.
Consequences
- The production method is limited to a specific cross-sectional shape. Other shapes can be provided using alternative production techniques.
In aluminum extrusion, rod material (solid, flat, round, or hexagonal) is pushed through a die with the desired shape under pressure. Extrusion can be performed in two ways, namely directly or indirectly, with both hot or cold aluminum.
Warm aluminum extrusion is performed at temperatures of 350 to 500 degrees Celsius. The advantage of warm extrusion is that it is easier to push the material through the die. The disadvantage of this is that lower tolerances are achieved. Cold aluminum extrusion is performed at room temperature. The advantages of this are that the aluminum gets a higher strength, better tolerances can be achieved, and the extrusion gets a better surface quality. The disadvantage of this is that less complex shapes can be extruded.
Direct Extrusion
Direct extrusion is the most common method of extrusion. In this process, the aluminum in the container is pushed through a stationary die with a ram. This method is also called forward extrusion. Direct extrusion is a (semi)continuous process, which means that theoretically, the aluminum can be produced endlessly. The disadvantage of this method is that there are high frictional forces, which can result in the formed aluminum being more susceptible to cracking and less strong.
Indirect Extrusion
In indirect extrusion, the die is pushed through the aluminum in the container. This method is also called backward extrusion. Indirect extrusion has the advantage that there are less frictional forces between the press and the container, which guarantees a longer lifespan of the machines. In addition, the formed aluminum has less chance of cracking and there are less imperfections in the surface. The disadvantage of this method is that the length of the extrusion is limited.
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