Designing Custom Aluminum Extrusions: 6 Things to Consider

custom-extrusionsRegardless of the type of work that you do or the purpose of the aluminum extrusion shapes that your company uses, designing aluminum extrusion is a serious business. With sizes ranging from .100″ to massively huge spans made from various types of aluminum alloys, there are a lot of variables to consider. There are a lot of basics that need to be considered when working with the design of custom aluminum extrusions, but there are also some unique parameters that designers can use to get some pretty amazing results.

#1 – Alloy
The type aluminum alloys that you use when designing aluminum extrusion shapes is important. There are many choices available, however there are a few that are used more commonly than others because of their inherent properties, such as strength, ease of use, surface finish and more. Here are some examples of the most commonly used aluminum alloys in the business of creating custom aluminum extrusions:

  • 7075 – The highest in mechanical strength of the four alloys that are used most often in designing aluminum extrusion pieces. These aluminum alloys are used frequently in structural components for aircraft due to their strength.
  • 6061 – This material retains a moderate level of mechanical strength. It machines very well and is used in many different types of industrial applications.
  • 6063 – Aluminum alloys in this category have a low mechanical strength. They are used most often in applications such as structural trim, doors and windows.
  • 3003 – This material has a very low mechanical strength. It is good for heat transfer applications, but is not in any way suitable for structural types of applications.

#2 – Temper
Another aspect associated with the type of materials that are chosen for creating aluminum extrusion shapes is the temper of the aluminum alloys. Using the same four most common alloys that we highlighted above, here is a run-down of the tempers associated with those alloys and why they might or might not be chosen over other options.

  • 7075 – These aluminum alloys are very difficult to extrude and have a very poor surface finish.
  • 6061 – Also very difficult to extrude than the other two aluminum alloys we will be discussing, this material has a nicer finish than the 7075.
  • 6063 – Easier to extrude than 6061, to which it is somewhat similar, these aluminum alloys have a good quality surface finish.
  • 3003 – The easiest to extrude of all of the aluminum alloys highlighted here, this material has a good surface finish.

#3 – Thickness
One of the areas in designing aluminum extrusion that many manufacturers overlook is the consistency and uniformity of the thickness of the walls within the aluminum extrusion shapes. Shapes with uniformed thickness will be the easiest to produce because the aluminum alloys flow through the die at a more even rate. Dies that have an unequal wall thickness can be difficult to produce effectively because the aluminum is forced through the widest sections the fastest, while moving slowly through the thinner areas.

If the thinner sections do not fill properly, the whole part made from the custom aluminum extrusions could become compromised and twist during manufacturing. Working with an experienced and highly knowledgeable service provider, such as Silver City Aluminum, is required in order to minimize the potentially negative effects associated with wall thickness variations.

#4 – Tolerances
The rule of thumb that should always be followed is that the larger the dimension of the shape that you are trying to create, the wider tolerance range that is required. One example of this would be that it is easier to hold a +/-.003″ tolerance on the diameter of a .500″ OD tube than it would be on a 1.000″ OD tube. For more information on the industry standard for tolerances, check out the Aluminum Standards and Data report that is published by the Aluminum Association. The creation of both standard extrusions and custom aluminum extrusions are covered in the book, which are applied to both shapes and tubing.

#5 – Corner Radii
To create truly successful custom aluminum extrusions, it is important for the designer to consider the corner radii. There are many instances where designing aluminum extrusion has seen the radii not really being considered. Some designers mistakenly believe that all corners will have sharp edges, but the truth is that the extrusion die tooling is cut with a wire EDM, which can produce rounded or unsharp corners. The larger the wire, the larger the radii that will be produced by the die. Custom aluminum extrusions, regardless of the aluminum alloys used, cannot be used to create anything with a radii that is less than .005″ as a rule of thumb.

#6 – Finishing
Once the desired aluminum extrusion shapes are created, many clients require additional finishing to be added in order for the pieces to be complete. There are many different types of finishing applications that can be added to create truly custom aluminum extrusions. Those finish applications include:

  • anodizing
  • center-less grinding
  • chemical conversion coating
  • cutting to length
  • drilling holes
  • machining
  • punching holes

Get Truly Custom Aluminum Extrusions at Silver City Aluminum
Manufacturers and businesses that work at designing aluminum extrusion shapes that would be considered custom, as well as standard aluminum extrusion shapes made from various aluminum alloys can trust Silver City Aluminum. Our team of highly trained and experienced technicians can help you create the standard or custom aluminum extrusions that you need using start-to-finish techniques at our one stop shop that will meet or exceed your expectations. Give Silver City a call today to get an estimate on your next project or to speak with one of our customer service agents to place an order.