Effects of Process Parameters on Anisotropic Mechanical Properties of 3D Printed Short Carbon Fiber‐Reinforced Polyamide Composites

ABSTRACT 3D‐printed short carbon fiber‐reinforced polyamide (SCF/PA) composites exhibit excellent mechanical properties, such as high strength and toughness, making them promising candidates for aerospace, automotive, and biomedical applications. However, the influence of key 3D printing parameters on mechanical behavior along the longitudinal (X), transverse (Y) and interlayer (Z) directions remains poorly understood. This study systematically investigated the effects of four process parameters, that is, nozzle temperature, layer thickness, printing speed, and extrusion multiplier, on porosity and anisotropic mechanical performance of the printed SCF/PA structure. A three‐levels Box–Behnken experimental design was used to construct the test matrix. Porosity was quantified by scanning electron microscopy analysis. Mechanical performance was evaluated through tensile tests along X and Y directions, and short beam shear tests along Z direction. Response surface models were developed to correlate the four printing parameters with porosity, longitudinal tensile modulus, longitudinal tensile strength, transverse tensile modulus, transverse tensile strength, interlayer shear strength. The mechanism of process parameters affecting anisotropic mechanical properties was confirmed by cross‐sectional morphology analysis of tested specimens. This study enhances the understanding of the relationships between printing parameters, printing defects, and anisotropic performance, thereby providing theoretical insights and methodological guidance for the performance‐oriented design of 3D‐printed composite components.