3D‐Printed Wood‐Fiber Reinforced Architected Cellular Composites

Abstract

One class of state-of-the-art lightweight, energy-efficient materials with enhanced material properties is "architected cellular solids." Their exotic properties (e.g., high strength-to-weight ratio, high energy absorption capability and tunable multiphysical properties) mainly stem from their rationally designed underlying architectures (e.g., cell topology and cell connectivity) and partially from the properties of their constituent materials. [1] Cellular solids, so-called cellular-based "metamaterials," upon showing unprecedented properties, have recently received considerable attention due to their potential applications in aerospace, automotive, energy, robotics and biomedical sectors as high-performance lightweight panels, energy absorbers, morphing structures, noise reduction, waveguide devices, programmable battery electrodes, and bioimplantable medical devices. [2] Recently, advances in "3D printing," interchangeably called "additive manufacturing" (AM), have shed light on strategies for design and realization of advanced materials (including "cellular solids" and "architected metamaterials") with controlled material composition and architectural complexity. A large number of studies have been conducted to investigate the correlation between specific mechanical properties and the architecture of 3D-printed advanced materials. [3] Fast prototyping, material saving, waste minimization, design freedom, and the capability to manufacture complex architectures are the main 3D printing advantages. [4] 3D printing is a fabrication process for constructing free-form materials and structures from a computer-aided design model. The printing process typically involves layerupon-layer fabrication that enables the production of complex geometries that would be impossible by conventional manufacturing processes. [5] Several methods can be adopted for 3D printing: direct metal laser sintering (DMLS), selective laser melting (SLM), and electron beam melting (EBM) for printing metallic powders; selective laser sintering (SLS) for printing polymeric and metallic powders; laminated object manufacturing (LOM), direct foam writing, 3D extrusion freeforming of ceramics (EFF), and lithography-based ceramic manufacturing (LCM) for ceramic-based materials; stereolithography apparatus (SLA) and digital light projection (DLP) for printing photopolymeric resins; and fused deposition modeling (FDM) for printing thermoplastic polymers. [6] The simplicity, reliability, affordability (minimal waste, low processing and operational cost), multimaterial (multinozzle) printing capability, and adaptability to new materials, and composites have made FDM one of the most

Biodegradable Poly(Lactic Acid) Nanocomposites for Fused Deposition Modeling 3D Printing

“… When aggregation occurs with cellulose-based additives, recycling and reprinting that material may lead to good dispersion [ 21 ]. Printing in an “isomixed” orientation produces materials that are stronger and have increased stiffness [ 44 ]. …”

“…Printing in an “isomixed” orientation produces materials that are stronger and have increased stiffness [ 44 ].…”

“…However, with the introduction of "isomixed" printing, a printing method where the printer prints crosshatched layers with each subsequent layer rotated by 45 degrees such that each new layer lies not perfectly on top but askew from each other as seen in Figure 4, there is an increase in properties. Isomixed microarchitectures of PLA/wood fiber nanocomposites show a 91% increase in stiffness and 48% increase in strength compared to neat PLA [44]. Cellulose, in the form of lignocellulosic fillers (LCFs), has also been incorporated into PLA/graphene nanoplatelet (GNP) nanocomposites to reduce the required GNP content and increase the mechanical properties of the materials.…”

“…Cellulose in the form of wood fiber also increases the mechanical properties of PLA. Adding wood fiber to the PLA filament and subsequent FDM 3D printing produced materials with increased stiffness (18%), toughness (44%), thermal conductivity (23%), fracture strain (15%), strength (9%), and decreased density (10%) [ 44 ]. In FDM 3D printing, the printer typically prints line by line, with subsequent layers depositing directly on top of the previous layer.…”

“…However, with the introduction of “isomixed” printing, a printing method where the printer prints crosshatched layers with each subsequent layer rotated by 45 degrees such that each new layer lies not perfectly on top but askew from each other as seen in Figure 4 , there is an increase in properties. Isomixed microarchitectures of PLA/wood fiber nanocomposites show a 91% increase in stiffness and 48% increase in strength compared to neat PLA [ 44 ].…”