Isotropy in 3D Printing: What Is It and How Does It Affect the Final Parts?

If you are part of the 3D printing industry or at least somewhat familiar with the technology, you will have heard of the concept of isotropy, which is defined as uniformity in all orientations. Thus, if we apply it to additive manufacturing, it refers specifically to uniformity in 3D printed parts. We can interpret this term from many different angles, whether it is the color, surface finish, shape of the model, etc. However, the property that most often interests experts, and to which the concept of isotropy is generally associated, is strength. In other words, an isotropic part is one that has the same strength in all the physical parts that make it up. But why is it so important to understand the meaning of this concept, and how does it affect the final 3D printed parts?

As 3D printing is an increasingly democratized manufacturing method, many companies are implementing it for the creation of final parts. It is therefore essential to understand the different technologies available and the performance of the material to be used. In general, most thermoplastic polymers are considered isotropic. This is mainly due to their nature and the fact that the cohesion between their component polymer chains is uniform in all directions. However, this does not mean that parts made from these materials maintain this quality level.

The difference between an isotropic and anisotropic model (Photo credits: IMA / Carbon)

In fact, sometimes the manufacturing method can cause anisotropy in the parts even though their raw material has isotropy. When this happens and anisotropic parts are obtained, it means that they have physical properties that are different depending on the direction in which they are measured. Let us now look at some techniques to maintain this degree of isotropy in 3D printing, focusing only on methods that work with polymers.