What Is Tolerance in 3D Printing?

When most people think of tolerance, what comes to mind is the ability to accept or tolerate somebody or something. However, there is another meaning when it comes to manufacturing and instrumentation, where tolerance is defined as the limit of allowable error. This understanding of tolerance is also important when we speak about 3D printing.

But what exactly does tolerance mean in the context of additive manufacturing? Well, to understand that, it is first necessary to delve into two other important characteristics of successful 3D prints: accuracy and precision.

Accuracy vs precision (photo credits: BMF)

Although these can be confused, they have very specific meanings in additive manufacturing. Accuracy, for example, is how close a measurement is to true value. A common example used to study it is a bullseye, for accuracy it would be hitting it. Or in other words, how the dimensions designed in CAD software are then equal to the final part.