5 Things to Think About:
- Critical Surfaces
- File Types To Submit For Review
- Dimensional Variation From End To End
- Rectangular Tube Tolerances
- Corner Radii
Every day Profile Precision Extrusions reviews aluminum extrusion designs. In many cases, we asked for additional information from the designer. These are the most common:
Surfaces
Critical Surfaces can be defined in a number of different ways. Some may be critical to the cosmetic appearance of the finished part. Others, such as some types of cylinders, have a maximum surface roughness which allows the part to operate reliably. Identifying these surfaces early in the design phase helps to ensure your aluminum extrusions are manufactured and perform as intended from the beginning.
CAD File Types
We receive a wide variety of aluminum extrusion designs and file types to review each day, from a sketch on the back of a napkin to the latest Solidworks files. We can work with almost all of them. Ideally, we would like to receive 2 files:
- A PDF file showing critical dimensions, tolerances and surface areas
- A DXF, DWG or Solidworks file
The PDF will help us understand the critical elements of your aluminum extrusion design. It will also help us identify the scale (English or metric) of your aluminum extrusion. The CAD file will help us if there are any areas that are unclear. In addition, it speeds up the process of designing the extrusion die once you’ve placed an order.
Dimensional Variation
The aluminum extrusion process naturally produces dimensional variation from one end to the other. For example, if one measures a .250” OD aluminum tube at each end of the 144” long piece, you may find one end measures .251” and the other .249”. The reasons are:
- Higher pressures required at the beginning of the process
- Lower temperatures at the beginning of the process
- Greater friction between the billet & container walls at the beginning of the process
During the extrusion process, we force a 16” long billet (a billet is a cylinder of aluminum) through an extrusion die. Heat is generated from the friction between the billet and the walls of the press containing the billet.
Rectangular Tube Tolerances
Not every shape we extrude is tiny. Pictured is a rectangular aluminum tube. The tolerances are very precise measured at the edges. However, the height tolerance as measured from the middle of the part is much greater. The tube naturally wants to bulge in or out at the middle of the part.
Corner Radii
- A ½” square bar with (3) different corner radii is depicted to the left.
- Most of our industry considers a 0.015” radius corner sharp.
- We regularly can achieve 0.010” radius corners.
- Upon request, we will consider producing 0.006” radius corners.
Thinking about these items ahead of time will speed up our review of your aluminum extrusion design, speed up manufacturing the extrusion die, improve the overall quality of the product & help to insure it fits together with mating parts during assembly. We’re experts at SMALL, so you can dream big. Contact us with your next aluminum extrusion design.
