Fully dense PLA blocks were manufactured by 3D-printing, depositing a polymer filament in a single direction via the fusion deposition method (FDM). Specimens were cut from printed blocks using conventional machining and were used to perform tension, compression and
fracture experiments along different material directions. The elasto-
plastic material response was found to be orthotropic and characterised by a strong tension-compression asymmetry; the material was
tougher when loaded in the extrusion direction than in the transverse direction. The response of the unidirectional, 3D-printed material
was compared to that of homogeneous injection-moulded PLA, showing that manufacturing by 3D-printing improves toughness; the
effects of an annealing thermal cycle on the molecular structure and the mechanical response of the material were assessed.