Abstract <p>The effect of nozzle diameter on the mechanical properties of polymers reinforced with short fibers is critical for optimizing both print quality and structural performance in fiber-reinforced composites 3D‑printed using fused filament fabrication. This study investigated three types of polymer composites based on acrylonitrile butadiene styrene reinforced with carbon, glass, and basalt short fibers. The study involved experiments on monofilament samples before and after manufacturing process to evaluate and compare the effective tensile strength and stiffness properties of filaments reinforced with different materials.</p>