Comparison of High-Throughput and Conventional Tensile Testing for 3D-Printed Polymers

Fused filament fabrication (FFF) is a promising three-dimensional (3D) printing technology that is used to print prototypes for numerous applications. However, FFF printing results in poor interlayer bonding and inadequate mechanical performance of the printed parts, limitations that hinder its application for printing fully functional objects. Here, the tensile properties of FFF-printed samples were evaluated using various volume compositions of polycarbonate (PC)- and polycaprolactone (PCL)-based filaments under different print conditions. As conventional uniaxial tensile testing can be time-consuming, this study developed and analyzed the utility of a high-throughput mechanical analysis (HTMECH) method for rapidly screening the tensile properties and interlayer bonding of FFF-printed samples. The tensile properties obtained by uniaxial tensile testing of dog bones were compared to properties obtained by HTMECH testing of single-layer and bilayer films. Uniaxial tensile testing results for dog bones printed from filaments with a lower glass transition temperature (T g ) revealed that an increase in extrusion temperature and a decrease in layer thickness result in a higher tensile strength, owing to better interlayer bonding. When HTMECH was used, although single-layer films followed the same trends as dog bones, bilayer films showed an opposite trend, namely, tensile strength decreased as the extrusion temperature increased. Owing to a poor correlation between uniaxial tensile test results on dog bones vs HTMECH results on bilayer films, both methods were used to characterize the sample geometry of dog bones. Using either method, PC-based single-material and multimaterial dog bones showed an increase in tensile strength as extrusion temperature increased, a trend that was attributed to better interlayer bonding at higher temperatures. In conclusion, HTMECH is a useful method for rapidly screening the mechanical properties of 3D-printed samples affected by interlayer bonding by reducing the testing time compared to conventional uniaxial tensile testing methods.