Simmal News
November 2008
20/11/2008
Design Considerations of Aluminium Extrusion Components
The process of extruding aluminium starts at the design stage and as aluminium components and profiles are becoming more and more popular to use as a material, the design opportunities seem endless. Upon finalising the purpose for the aluminium extrusion and machine and finishing requirements are answered, then the choice of alloy can be decided upon. Not forgetting the die, which will be designed around the profile for the extrusion?
Most shapes can be extruded however; there are some design considerations, which may need to be taken into account for your aluminium component such as simple shapes, wall thickness, sharp or rounded corners, symmetrical, size to weight ratio and tolerances - industrial standards
Simple Shapes
Although a wide variety of aluminium component shapes can be extruded some factors need to be taken into consideration. The more complex the design the more material could be required and hence a higher cost. Simple Shapes are the most cost effective, as the dies will be relatively less problematic; the more complicated the shape the more expensive the die costs will be.
Wall Thickness
Differences in wall thickness on a section can cause problems and should be avoided.
Sharp or Rounded Corners
Generally all corners are rounded and sharp corners avoided.
Symmetrical
If an extrusion shape is symmetrical it will be more accurate.
Tolerances
Tolerances are added to sections to allow for any distortions, which may occur during the extrusion process.
Simmal conform to standard tolerances on design & form supplied to BSEN 755.
Standard material composition supplied to BSEN 573. Other standards of tolerance and composition can be considered on request.
09/11/2008
Extrusion process
Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section. The two main advantages of this process over other manufacturing processes is its ability to create very complex cross-sections and work materials that are brittle, because the material only encounters compressive and shear stresses. It also forms finished parts with an excellent surface finish.
Extrusion may be continuous (theoretically producing indefinitely long material) or semi-continuous (producing many pieces).
SIMMAL specialise in aluminium extrusions.
History.
In 1797, Joseph Bramah patented the first extrusion process for making lead pipe. It involved preheating the metal and then forcing it through a die via a hand driven plunger. The process wasn't developed until 1820 when Thomas Burr constructed the first hydraulic powered press. At this time the process was called squirting. In 1894, Alexander Dick expanded the extrusion process to copper and brass alloys.
Aluminium is the most commonly extruded material. Aluminium can be hot or cold extruded. If it is hot extruded it is heated to 575 to 1100 °F (300 to 600 °C). Examples of products include profiles for tracks, frames, rails, mullions, and heat sinks.
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