Introduction

3D Printing, like any real-world system, has error. This can negatively impact designs that utilize friction or perfect fit for parts. Follow this guide in order to get the appropriate fit for parts.

Printer Type

Tolerancing will highly depend on the type of 3D printer you are using and the resolution you select. Below is a scale of printing resolution by type of 3D printing method (in general).

Printing Accuracy:

1. Multijet (Projet, Objet, etc.)
2. Stereolithography (SLA)
3. Selective Laser Sintering (SLS)
4. Fused Deposition Modelling (FDM)

Guess and Check Method

One efficient way to get appropriate tolerancing is to print an array of tests that all have different tolerances to see which one provides the correct fit. This works best if you are able to create models which simulate the tolerances you need in larger parts so that you can load up a print job with many sizes.

This strategy can be utilized on in-house printers as well as with outsourced parts. You can send a set of test fit parts to the vendor for a lower cost (smaller parts) to find the proper fit. Then once you have the correct fit dialed in, you can apply it to your larger prints.

Examples:

Outsourcing Support

If you decide to outsource your part's printing to a rapid manufacturing company (e.g. ProtoLabs), here are a few tips:

1. Search their website for information on tolerances, companies will most likely have these listed with a specific material/process.
   1. Confirm the tolerances with your desired method to prevent unnecessary failures/delays!
2. If you cannot find it on their website, contact their customer support for assistance
   1. Feel free to reach out, submitting a part with strict design tolerances without confirming compatibility will be costly and time-consuming