Interlayer Mechanical Properties of Thermoset Components Produced by Material Extrusion Additive Manufacturing

Material extrusion additive manufacturing (MEX-AM) with thermoset media is of interest as its unique material properties are advantageous for many applications. However, thermoset MEX-AM’s resultant interlayer mechanical properties have not yet been fully ascertained. In this study, a robot arm and extrusion system are used to 3D print a two-component polyurethane with depositions of varying holding intervals between layers, to quantify the effect on interlayer- stiffness and –strength. The material is extruded through a 7 mm nozzle to fabricate 42 mm high walls with a width equal to a single strand. The bulk- and interlayer mechanical properties are measured through tensile testing of dogbone samples. The results indicate that the interlayer mechanical properties do not reduce as compared to the bulk behavior.