What does the term "anisotropic" refer to in the context of layer build limitations?

In the context of layer build limitations in Fused Deposition Modelling (FDM), the term "anisotropic" refers specifically to the variation of strength in specific directions. This means that materials printed using this process can exhibit different mechanical properties, such as tensile strength or impact resistance, depending on the direction in which the load is applied.

For instance, when layers are deposited, the bonding between successive layers may not be as strong as within the layers themselves, which can lead to this directional dependency in strength. If a force is applied parallel to the layers, the component may perform well, but if the force is applied perpendicular to the layers, it may fail more easily. Understanding this property is crucial for engineers and designers to ensure that parts will behave as expected under operational conditions.

The other options focus on different aspects, such as the ability to carry loads in various directions or the uniformity of layers, which don't directly define anisotropic behavior in terms of material strength and properties. The microscopic structure of the filament while relevant to material characteristics, does not address the directional strength properties associated with anisotropy. Therefore, the idea of variation in strength specific to certain directions captures the essence of anisotropic behavior in FDM printed parts.