Characterizing the effect of additives to ABS on the mechanical property anisotropy of specimens fabricated by material extrusion 3D printing

Material extrusion 3D printing (ME3DP), based on fused deposition modeling (FDM) technology is currently the most widely available 3D printing platform. As is the case with other 3D printing methods, parts fabricated from ME3DP will exhibit physical property anisotropy where build direction has an effect on the mechanical properties of a given part. The work presented in this paper analyzes the effect of physical property-altering additives to acrylonitrile butadiene styrene (ABS) on mechanical property anisotropy. A total of six ABS-based polymer matrix composites and four polymer blends were created and evaluated. Tensile test specimens were printed in two build orientations and the differences in ultimate tensile strength and % elongation at break were compared between the two test sample versions. Fracture surface analysis was performed via scanning electron microscopy (SEM) which gave insight to the failure modes and rheology of the novel material systems as compared to specimens fabricated from the same ABS base resin. Here it was found that a ternary blend of ABS combined with styrene ethylene butadiene styrene (SEBS) and ultra high molecular weight polyethylene (UHMWPE) lowered the mechanical property anisotropy in terms of relative UTS to a difference of 22 ± 2.07% as compared to 47 ± 7.23% for samples printed from ABS. The work here demonstrates the mitigation of a problem associated with 3D printing as a whole through novel materials development and analyzes the effects of adding a wide variety of materials on the physical properties of a thermoplastic base resin.