Control or Affect? The Paradox of 3D‐Printed Wood

Yin, R. K. 2018. Case Study Research and Applications: Design and Methods. Thousand Oaks, CA: SAGE Publishing. depositing multiple layers of material. Feedstocks typically consist of polymers, although other materials including metals, glass, and clay are also employed. Wood is a relative latecomer to the 3D printing sphere (the first filament was commercialized in 2012) because its individual ingredients burn, rather than melt, when heated. The cellulose, hemicellulose, and lignin in wood fiber must first be chemically or mechanically modified and/or blended with other materials to support Fused Deposition Modeling (FDM) and other AM processes commonly used today. For example, researchers at the Wallenberg Wood Science Center at the Chalmers University of Technology in Sweden created a printable medium from cellulose nanofibrils mixed with hydrogel.2 This gelatinous slurry, composed of over 95 percent water, is suitable for printing three-dimensional structures that retain their shape when dried in controlled conditions. Another approach combines fine wood particles with a printable polymer rather than separating the wood’s individual components. WoodFill, a 3D printing filament commercialized by the Netherlands-based company Colorfabb, consists of 30 percent recycled wood fibers and 70 percent polylactic acid (PLA), a bioplastic. Laywoo-D3, a filament created by German inventor Kai Parthy, consists of 35 percent recycled wood and 65 percent copolyesters.3 Because the bulk of additively manufactured wood is made with PLA and other polymers, the material is more accurately described as wood-plastic composite (WPC).4 The 3D printing of composites has become increasingly popular as a way to achieve sophisticated geometries at relatively low cost in a variety of media. The impetus to expend the additional effort to create printing media based on wood, rather than using more readily accessible polymer feedstocks, has two primary motivations. One is to replicate the effect of wood by mimicking its appearance, tactility, and even smell in a process that creates objects with extreme precision. The other is to create a more environmentally responsible 3D printing medium—a goal made possible by using repurposed feedstocks, such as repurposed waste wood, and bio-based polymers instead of petroleum-based plastics. San Leandro, Control or Affect? The Paradox of 3D-Printed Wood