Considerations when Designing Parts for Aluminum Extrusion
For many design engineers and product designers, extruded aluminum is the material of choice for products across a wide range of industries. While aluminum extrusion provides nearly unlimited design possibilities, it also requires several design considerations. When designing for aluminum extrusions, practitioners will benefit from a solid understanding of the extrusion process, aluminum alloys, fabrication techniques, optimum tolerance, and proper profile design—knowledge that many designers do not possess or have time to acquire.
The experience in manufacturing aluminum extrusions at Nice Rapid has taught them about taking time to consider the intricacies of extrusion design in the beginning stages of the project to consistently achieve the best results.
A well-designed aluminum extrusion will ensure cost-effective tooling, avoid production issues and reduce lead times from inception to delivery - therefore, a little forethought can go a long way.
To achieve a seamless aluminum process, let us look at the eleven crucial points before embarking on an aluminum extrusion process.
Design Considerations for Aluminum Extrusion
The following key characteristics should be addressed during the aluminum extrusion design process.
1. Regular wall thickness
To avoid risking distortion or damage to the profile, you need to have sufficient metal thickness. This thickness should be enough to support the structural requirement. Shapes tend to result in distortion during the aluminum extrusion process, especially when the metal thickness is either too thin or not uniform.
Avoiding thin details in the design and designing profiles of different thicknesses will avoid the risk of becoming distorted, damaged, or failing during the extrusion process.
2. Limit the design details in hollow parts
Since aluminum extrusion is a continuous process, defining the interior of the hollow sections can be difficult to achieve as there is no way of getting inside the hollow to hold the detail in place during the forming process. You can only do complex details when you open the part.
3. Avoid putting hollows in hollows
Accommodating a design with a hollow inside the hollow is challenging in an aluminum extrusion process. If that is the design, it will inevitably force the intended design out of shape before the material solidifies.
4. Provide good access to internal details
If the extrusion design has an opening, grooves, legs, or snap-in features and other details are possible to incorporate internally.
5. Length tolerances
It is easier to produce tolerances when the dimensions are measured across solid metal instead of measuring to a centerline or hole. Metals can be extruded to close tolerances where open space dimensions are more difficult to hold the tolerance as they cannot be measured accurately during the extrusion process.
6. Design with the surface finish in mind
When designing for aluminum extrusion, define the surface finishes required. This is for the manufacturer to pay extra attention to finish during both extrusion and post extrusion process.
Any changes in metal thickness can show up as marks on the opposite surface of an extrusion, especially on thinner sections, to minimize marking on exposed surfaces with a good design.
7. Make smooth transitions
When there are thick to thin junctions, streamline the transitions with a generous radius, By rounding the corners, you can achieve smoother transitions.
8. Add web for dimensional control
The hollow part of the design can be extruded successfully by adding a web to the design whenever possible. It will allow the extrusion of thinner wall sections. This extra effort is beneficial because it is easier to extrude compared to gap and angle dimensions that leave a long hollow.
9. Reduce twists by introducing ribs
After aluminum extrusion, the thin, wide sections are difficult to straighten. Introducing ribs into the design. It can reduce twisting and improve the flatness of the final product.
10. Avoid sharp corners to strengthen the tongue
If the design has a void, use rounded corners instead of sharp corners. It will prevent the die tongue from snapping at the slimmest area of the void. Rounded corners are stronger and easier to extrude too.
11. Incorporate index marks
Incorporating index marks on the part will make drilling, punching, and assembly more convenient because it eliminates the need for center punching. Index marks can also help to differentiate the inside surface and outside surface.