Rethinking Timber: Investigation into the Use of Waste Macadamia Nut Shells for Additive Manufacturing

In this article, the feasibility of turning macadamia nutshells, a waste product from the forestry and agricultural industries, into a three-dimensional (3D) printed, innovative, microtimber product is examined by composing a wood plastic feed stock for fusion deposition modeling. Different ratios of microground macadamia nutshells and acrylonitrile butadiene styrene (ABS) plastics were mixed with a binding agent to extrude a range of filaments. By using a commercial 3D printer, these filaments helped to fabricate specimens that were tested in tension and compression. The results show that printed samples of macadamia-nutshell-ABS composites offer a viable alternative to commercially available wood polymer composite filaments. Although they possess similar mechanical properties, they have a lower density, making them suitable for a range of lightweight product applications. The research demonstrates that there are new opportunities for the use of macadamia nutshell filament in additive manufacturing as a result of its enhanced properties compared with traditional wood filaments.