Z-Pinning Approach for Reducing Mechanical Anisotropy of 3D Printed Parts

Duty, Chad
Failla, Jordan
Kim, Seokpum
Smith, Tyler
Lindahl, John
Roschli, Alex
Post, Brian
Love, Lonnie
Kunc, Vlastimil
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University of Texas at Austin

The mechanical strength of extrusion-based printed parts is often greatly reduced (25-50%) in the build direction (z-direction) compared to the in-plane strength due to poor bonding between successively deposited layers. This effect can be magnified (75-90% difference) when depositing fiber-reinforced materials or larger print areas with long layer times. Therefore, a patent-pending approach has been developed that deposits material into intentionally aligned voids in the z-direction, allowing continuous material to span multiple layers. The “z-pinning” approach can be applied to several concepts for improving the interlaminar strength of extrusion-based 3D printed parts as well as techniques for applying the technology across a broad spectrum of deposition platforms and material systems. Initial experimental results demonstrate a significant improvement (>3x) in mechanical strength and (>8x) toughness for fiber reinforced components.