Browsing by Subject "mechanical anisotropy"
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Item Reducing Mechanical Anisotropy in Extrusion-Based Printed Parts(University of Texas at Austin, 2017) Duty, Chad; Failla, Jordan; Kim, Seokpum; Lindahl, John; Post, Brian; Love, Lonnie; Kunc, VlastimilThe 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.Item Z-Pinning Approach for Reducing Mechanical Anisotropy of 3D Printed Parts(University of Texas at Austin, 2018) Duty, Chad; Failla, Jordan; Kim, Seokpum; Smith, Tyler; Lindahl, John; Roschli, Alex; Post, Brian; Love, Lonnie; Kunc, VlastimilThe 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.