Property-map of epoxy-treated and as-printed polymeric additively manufactured materials
Nha Uyen Huynh, Jordan Smilo, Aryan Blourchian, Arbi V. Karapetian, George Youssef
Abstract
Additively manufactured, or 3D printed, polymer structures are becoming widespread across many industries including the medical, automotive, and aerospace fields. Contrary to conventional manufacturing techniques, such as injection molding and machining, the cost-effectiveness, quick time-to-market, and ability to manufacture complex geometries make 3D printing a desirable alternative. However, the layer-by-layer process of 3D printing gives rise to poor adhesion strength between the polymer layers, defects and voids, as well as mechanical anisotropy. To investigate the latter, the study herein examines the stress-strain responses of different print orientations for 3D printed ABS samples subjected to tensile, compressive, and flexural loading. The physical properties of samples with the same print conditions and additional post-processing chemical treatment are also considered to include a comprehensive characterization protocol. Despite the print orientation (horizontal, sidewise, and vertical), the elastic modulus and strength at tensile failure of the 3D printed ABS were found to be less than its cast counterpart, by 41% and 46%, respectively. The experimental compressive mechanical properties were predicted, within a 2% error, by using the ratio of the overall cross-sectional area of the horizontally and vertically printed samples. Furthermore, the flexural stiffness and failure were found to be dominated by the tensile loading seen in the section of the sample below the neutral axis. The resulting average moduli and strengths were compiled onto a property-map to delineate the property-process interrelationship of 3D printed ABS, including the effect of diluted epoxy treatment and the dependency of print orientation on its mechanical behavior. In general, the property-map defines the design envelope to gauge the mechanical integrity of 3D printed ABS in different modalities and directionalities.