Effect of selected printing settings on viscoelastic behaviour of 3D printed polymers with and without wood

Abstract

The viscoelastic behaviour of 3D printed samples produced from different types and contents of commercially produced filaments of wood and thermoplastics at different printing settings was investigated in this study. An Ares G2 rheometer was used to carry out the dynamic mechanical analysis (DMA) of the printed materials. A strain sweep and a temperature ramp test were made to evaluate the effect of 3D printing settings, materials, and temperature on the properties of the 3D-printed specimens. Five different printing materials (ABS, PLA, co-polyesters, mixtures with different wood content) and three printing layer thicknesses (0.09, 0.19, 0.29 mm) were used. The result showed that the specimens printed from Filament C (polymer blend of co-polyesters) had the lowest storage modulus while the highest modulus was found in the PLA based samples. When comparing pure PLA and PLA-wood filaments, the addition of wood particles decreased the storage modulus by 40%. The glass transition temperature (Tg) of the materials differed with each other. The specimens printed from ABS had the highest Tg 115 °C, followed by the specimens printed from co-polyester-based filament (around 70 °C), pure PLA, and PLA-wood filaments (64 °C–66 °C). The addition of wood did not change the glass transition temperature, since the main matrix was made of polymer. The viscoelastic behaviour of the 3D printed neat polymer and wood/polymer parts produced at different processing parameters and conditions can be considered for filament producers for material selection and the design engineers when wood/PLA printed parts fabricated through FDM technique.