Aluminum Extrusion Key Design Considerations 

Aluminum extrusions are available in an extremely wide range of shapes and sizes, and extrusion tooling is generally far lower cost than stamping dies. However, every manufacturing process has some limitations. For aluminum extrusions, there are practical limits; some designs prove very challenging to extrude, while minor tweaks to an extrusion profile design can often yield significant benefits in extrudability, and consequently, lower cost.

Below are several factors to consider when designing with aluminum extrusions:

Diagram showing the largest diameter size of a cross section for an extrusion

Overall Cross Section Size

One common measurement of the size of an extrusion is the diameter of the smallest circle that will entirely enclose its cross-section, or its circumscribing circle diameter (CCD). The dimension is one factor in the economics of an extrusion. Most common profiles are less than 12 inches in diameter, while a few extruders are capable of producing extrusions with a much larger CCD, some as large as 32 inches. See the Press availability chart below.

The dimension of the profile is one factor in the economics of an extrusion. In general, extrusions are most economical when they fit within a CCD between one and ten inches. Profiles below 8-inches of CCD reduce costs significantly.  

Weight-per-Foot (Wt/Ft)

The weight-per-foot of a profile is important because of the effect it has on profitable press operation. Is the profile too heavy? Is it too light? Many factors affect press operation and the press size required to extrude a profile. Your extrusion partner will provide the information you need to improve your profile design to extrude cost effectively.

Generally, the design is greatly enhanced if the profile CCD is kept under 8 inches and the wt/ft is 3 pounds or less.

Diagram showing tongue ratio of an extrusion

Shape Constraints

Avoid high tongue ratios (width of a fin vs. height of a fin). Where possible, reduce deep, narrow "tongues" by redesigning the profile. Also, keep somewhat balanced wall thicknesses. Below are some things to keep in mind when designing your profile.

Good Aluminum Extrusion Design Practices

  • Balanced walls
  • Avoid/minimize hollows
  • Generous tapers
  • Practice symmetry/minimize asymmetrical detail
  • Use grooves, webs, and ribs
  • Minimize perimeter/cross-section ratio

Availability of press sizes

Keep in mind the various profile circle size/area/weight combinations and the press sizes available to handle them. Below is a chart showing the general availability of press sizes in North America. Keep this in mind when designing your profile as it will affect the extrusion cost.

ALUMINUM EXTRUSION MANUAL

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