Aluminum Extrusion Design: Key Specs That Must Be Considered

key-specs-designWhen it comes to designing a custom aluminum extrusion to be used in manufacturing, architecture or any other industry, it is important to consider the specifications that will be required before making any decisions about the final design. Aluminum extrusion design encompasses a wide variety of products that can come in an unlimited array of shapes and sizes.

As a provider of precision designed aluminum products to many different industries around the world, Silver City Aluminum has seen some pretty unique designs get submitted by our clients. As a result, we have learned through experience the five primary areas that must be considered with regard to design specs in order to achieve the desired results. This article will focus on those five areas, providing you with useful insight into important choices regarding aluminum alloys, post extrusion operations and more.

The Five Areas of Consideration
Before you finalize the design for your custom aluminum extrusion, you will want to consider these five areas of your specifications. Each one plays a part at the final success of your finished aluminum product. The five areas that we will be discussing include the alloy and temper, thickness of the wall, tolerances, corner radii and the final area of consideration, post extrusion finishing.

Step One: Choosing an Alloy Based on Performance
There are many different aluminum alloys to choose from when working with aluminum extrusion design. Choosing to extrude aluminum alloys based upon temper and performance should always be your primary concern. Some of the most common types of aluminum alloys used in custom aluminum extrusion include:

  • 7075 – This alloy is very difficult to extrude and results in a very poor finish on the surface. As a result, it is used in structural components of aircraft and has a very high mechanical strength.
  • 3003 – On the opposite end of the spectrum, 3003 is very easy to extrude, which makes it an excellent choice for heat transfer applications. Due to its easy extrusion abilities, it has a very low mechanical strength.
  • 6063 – While not as easy to extrude as 3003, 6063 is still an easy choice for custom aluminum extrusion. While it does have a low mechanical strength, it has an excellent surface finish, making it a popular choice for windows, doors and trim.
  • 6061 – Closer to 7075 in terms of being difficult to extrude, 6061 has a much more acceptable looking surface finish, making it a great choice for a wide variety of different industrial applications. It machines well and has a moderate mechanical strength.

Step Two: Minimizing Problems in Aluminum Extrusion Design
Once you have made a selection to extrude aluminum alloys based upon the industry and use of the finished product, it’s time to start thinking about wall thickness. Through our years of experience we have come to realize that a design that features a more uniform wall thickness will be the quickest and easiest to produce. This allows the aluminum to flow at an even rate.

If there are unequal wall thicknesses, sometimes the aluminum will flow quicker through the wider areas and slower through the thin areas. This can result in a finished product that is more likely to twist or bend during production. As a result, if it is at possible, designers should work with the idea of presenting a die that is uniform in order to minimize the problems associated with unequal custom aluminum extrusion.

Step Three: Why Tolerances Matter in Aluminum Extrusion
If you are unfamiliar with tolerances, you can work with our technicians to discuss our recommendations or you can check out the industry standard for tolerances in the Aluminum Standards and Data publication. The standard is published by the Aluminum Association and it covers standard extrusions as well as custom, precision tolerances for extruding shapes and tubing.

What you need to keep in mind is, the larger the dimension of the design, the wider range for tolerance that will be required. One example of this would be a better tolerance of a +/-.003″ using a .500″ OD tube versus choosing to use a 1.000″ OD tube. Again, if you have any questions about tolerances with regard to aluminum extrusion design, speak with one of our experienced technicians. We can help you get through this part of the design process.

Step Four: The Importance of Corner Radii
Especially in designers that are new to custom aluminum extrusion, we see a lot of designs come through where the idea of determining the corner radii is not really considered. Because it is made from metal, many designers just assume that all of the corners for their design will be sharp. However, because of the way that the extrusion die tooling is cut using a wire EDM, the corners are most definitely not sharp.

When it comes to aluminum extrusion design, the wire diameter that is used to cut the tool steel will have a huge impact on the final result of the corner. For example, a large wire will create a larger radius. While there are limits to the ability of extrusion based upon the process itself, it is good to remember that a radius of less than .005″ is not possible. If you have any questions about how this part of the process is configured, please speak with one of our qualified technicians or customer service agents.

Step Five: Post Extrusion Operations Provide Options to Design
Another way to further customize your aluminum extrusion design is to consider selecting from our list of post extrusion operations. These are also sometimes known as “secondary” operations within the industry, indicating that they are done after the initial process to extrude aluminum alloys according to the client’s specifications. Below is a list of some of the post extrusion operations that Silver City Aluminum provides:

  • anodizing
  • painting
  • powder coating
  • cut to length
  • punching holes or drilling
  • de-burring
  • heli-coiling
  • assembly

Custom Aluminum Extrusion at Silver City Aluminum
To learn more about all of the services and capabilities available at Silver City, contact our office in Taunton, Massachusetts or use our online form. Our team of highly trained and experienced technicians can create a precision aluminum extrusion design for you in just about any size or shape that you might require. Give us a call today and we will help you get started on your next aluminum extrusion project.