How to Choose the Right CNC Material for Your Part

Regardless of your industry, choosing the right material is one of the most important components in determining the overall functionality and cost of your part. Here are 4 quick tips for choosing the right material!

By Shilpa Garg · July 23, 2018

Material selection is a critical component in determining the overall functionality and cost of your part. In a previous post, we discussed the strengths and trade-offs of the different types materials that can be milled and turned.

Here are a few additional guidelines to consider for choosing the metal or plastic that’s right for your part!

5 Axis Pronged

What will your part be used for?

The environment where your CNC part will be used will have the most significant impact on material selection. For example, if you’re using your part outside or in wet environments, use Stainless Steel as opposed to Carbon Steel so your part won’t rust.

Design specifications like stress load, tolerance, and types of fastening (welding, rivets) can also impact your choice of material, as can specifications such as for military and aerospace parts or FDA-regulated environments.

Small Parts

Does weight matter?

In general, standard aluminum alloys like 6061 are great, low-density options to keep weight down if a metal is required. Plastics like Delrin and ABS can help keep the weight down even more if tradeoffs in strength can be made.

CNC Metal Red

Strength and heat resistance

There are many different ways to measure material strength including tensile strength, material hardness, and wear resistance. Selecting the types of strength your design calls for will allow you to get the best material for your part.

Likewise, very low or very high temperatures will also restrict you from using certain materials. Environments where the temperature fluctuates are particularly important to consider since some materials will expand or contract considerably even with small temperature changes.

Bin Full of Cylindrical Parts


The manufacturability and overall cost of your project will influence your choice of material. The more material your part uses, the more expensive it will be. Likewise, specialty materials and strong materials, like titanium, will also cost more.

For more information on which material is best for your parts, you can contact our expert engineers via You can upload your 3D CAD file directly on the Xometry Instant Quoting Engine℠ or use our free SOLIDWORKS or Autodesk Inventor Add-In for instant quoting and manufacturability feedback.

Posted in Machining Manufacturability Tips