Effects of Infill Density, Heat Treatment and Geometry on the Tensile Strength of 3D Printed ABS Specimens

Additive Manufacturing is a relatively new technology that allows to produce intricate parts with geometries that cannot be achieved through conventional manufacturing methods. One of the most widespread methods of 3D printing is Fused Filament Fabrication (FFF). In this study different 3D-printed, bone-shaped specimens made out of ABS (acrilonitrile-butadiene-styrene) are tested, complying with norms for mechanical testing of polymeric materials, with variations on its printing parameters (percentage of infill density), shape (thickness of specimen), and an annealing heat treatment. The resistance to tension is measured, and compared. The stress-strain curves were gathered from the universal tension tester from each of the specimens. Finally a statistical method is used in order to correlate the obtained behavior with a function that predicts the tensile strength of the part based on the parameter that can be varied, whether or not the heat treatment has a meaningful effect on the part that is to be produced, and if a lesser ratio of cross-sectional area to volume has a negative effect on the tensile properties. The resulting models showed a more pronounced decrease of tensile strength as the infill density is reduced, as well as a measurable and positive impact of the heat treatment on the ultimate tensile strength of the specimens. Finally the change in ratio of area to volume doesn't conclusively show a difference in tensile strength.