Evaluation of Mechanical Anisotropy of New Polycarbonate Through Process Parameter Optimization in Material Extrusion

The parts fabricated using the material extrusion (MEX) process exhibit anisotropic mechanical properties depending on the build orientation, primarily due to incomplete interlayer bonding. In this study, a new polycarbonate (PC) is adopted, and the anisotropic behavior of parts produced from this material is quantitatively investigated in MEX. First, we examine the deformation behavior of the material extruded (MEXed) parts according to chamber temperature. Additionally, we evaluate the surface roughness of MEXed parts as a function of the nozzle temperature. Finally, to identify the tensile strength anisotropy, tensile tests are conducted on MEXed specimens in two deposition directions using three nozzle temperatures that produced superior surface roughness. As a result, a PC adopted in this study exhibits relatively low tensile strength anisotropy, indicating that it is well suited for the MEX. Overall, this study not only provides a systematic procedure for optimizing the process parameters when adapting a new polymer to MEX, but also offers practical guidance for evaluating tensile strength anisotropy to determine whether the material is suitable for MEX.