Authors: John Mai, Jordan Girdis, Gwénaëlle Proust, Andy Dong and Sandra Löschke
The 3D printing of wood-plastic composites (WPC) is an emerging field of advanced fabrication with enormous innovative potential: it opens up the possibility of masscustomising architecturally designed structures and allows us to create innovative fusion material that can improve on the qualities of natural wood whilst retaining its inherent aesthetic appeal. Through the manipulation of the material composition and the variables of the fabrication process, the aesthetic appearance of WPCs can be modified significantly. In particular, changing the temperatures to which WPCs are exposed during the fused filament fabrication (FFF) process permits the production of grain patterns, whereby higher temperatures produce increasingly darker shades. This paper analyses the effects that changes in processing temperatures have on the aesthetics and mechanical properties of WPCs, in particular tensile strength, failure strain and elastic modulus. Two commercially widely available WPC filaments were selected for testing: Laywoo-D3 and Woodfill WPC. For Laywoo-D3, it was found that there was no significant variation in tensile strength and elastic modulus over a wide range of temperatures, and a reduction in failure strain at higher temperatures. For Woodfill, an increase in tensile strength and elastic modulus was observed at higher temperatures, while there was no appreciable trend in the failure strain. The small variation in strength for a wide range of different processing temperatures highlights that the functionality of WPCs for strength applications is independent of the temperature variations which is used to create the surface aesthetic. However, WPCs with larger fibres would be more structurally sound, which may contribute to the higher strength of Woodfill. Conversely, Laywoo-D3 WPC filament has the ability to create different shades with varying temperatures, which suggests a higher proportion of wood fibres in WPCs allow the freedom to create a more varied aesthetic during the 3D printing process.
Keywords: wood-plastic composite, temperature effect, fused filament fabrication, 3D printing, additive manufacturing