Effects of sandwich core structure and infill rate on mechanical properties of 3D-printed wood/PLA composites

This study aimed to understand the effects of core configuration on the mechanical properties of additively manufactured specimens made of commercial wood/PLA filament through 3D printing. The wood/PLA specimens with different infill rates and pattern types, such as square, hexagonal, and octagonal, were manufactured using a 3D printer. The process parameters in the production of the 3D-printed specimens were kept constant, except for the core configuration. The outside layer thickness was kept constant for all the specimens. The specimens with a hexagonal pattern had the highest mechanical properties, followed by the square and octagonal core patterns. In terms of infill rate, the mechanical properties sharply increased with increasing infill rate. In particular, when the infill rate increased from 20 to 50%, the rate of increase in the mechanical properties was significantly higher than that seen from 50 to 80%. The highest rate of the elastic recovery after the Brinell hardness tests was found in the specimens with hexagonal cores, followed by square- and octagonal-shaped cores.