Material extrusion 3D printing of biodegradable composites reinforced with continuous flax fibers

Abstract

Fabricating additively manufactured thermoplastic parts with increased load-bearing capacity using material extrusion, namely fused deposition modeling, requires the incorporation of continuous reinforcing fibers. In this study, composites of PLA matrix and continuous flax fibers were additively fabricated using a specially designed 3D printer with multiple deposition toolheads. Unidirectional tensile and flexural specimens with a component-like shape and a fiber volume fraction of up to 18% were fabricated. The mechanical properties were determined for four different composite and matrix layers arrangements. The tensile modulus of elasticity and strength values increased by 3.6 and 2.9 times, respectively, compared to the specimens without the reinforcing fibers. In contrast, the flexural modulus of elasticity improved by 2.4 times, while the flexural strength increased by 1.4 times. It was found that it is possible to influence the mechanical properties and the type of damage by changing the volume fraction of the fibers and the arrangement of the composite layers.