Effects of Injection Molding Parameters on Fiber States and Mechanical Properties of Carbon‐Fiber‐Reinforced Polyamide

ABSTRACT This study systematically elucidates the comprehensive influence of back pressure and screw speed—two key processing parameters in injection molding—on the fiber‐state characteristics and mechanical performance of carbon‐fiber‐reinforced polymer composites. High‐precision characterization of fiber dispersion, fiber orientation, and fiber length was achieved using advanced image‐recognition techniques. Building on these results, the underlying mechanisms by which injection‐molding parameters govern the mechanical behavior of the composite were further clarified. The experimental results indicate that both back pressure and screw speed exert nonlinear effects on the tensile strength. The data show that the tensile strength reaches a maximum of 262 MPa at a back pressure of 8 MPa, while the highest tensile strength of 261 MPa is obtained at a screw speed of 90 rpm. This study advances the understanding of the relationships among processing parameters, fiber‐state characteristics, and mechanical performance, and serves as a valuable case study for the application of artificial intelligence in composite process optimization, macro‐scale characterization, and failure analysis.