Reducing Mechanical Anisotropy in Extrusion-Based Printed Parts
Abstract
The mechanical performance of 3D printed components is highly dependent upon the
orientation of the part relative to the build plane. Specifically for extrusion-based printing systems,
the bond between successive layers (z-direction) can be 10-25% weaker than in the printed plane
(x-y plane). As advanced applications call for fiber reinforced materials and larger print systems
(such as the Big Area Additive Manufacturing system) extend the layer time, mechanical
performance in the z-direction can decrease by 75-90%. This paper presents a patent-pending
approach for improving mechanical performance in the z-direction by depositing material
vertically across multiple layers during the build. The “z-pinning” process involves aligning voids
across multiple (n) layers, which are then back-filled in a continuous fashion during the deposition
of layer (n+1). The “z-pinning” approach has been demonstrated to be an effective approach for
increasing the strength (20% increase) and toughness (200% increase) of printed parts in the z-direction.