Advances in Additive Manufacturing of Basalt Fiber Composites: A Review of Fiber Orientation, Defect Mitigation, and UHMWPE Hybrid Systems for Lightweight Structures

Basalt fiber-reinforced polymer composites (BFRPCs) are increasingly recognized as sustainable and structurally efficient alternatives to conventional glass- and carbon-fiber systems for additive manufacturing (AM), owing to their volcanic origin, cost competitiveness, and favorable balance of mechanical, thermal, and chemical stability. Basalt fibers exhibit high tensile strength, exceptional chemical inertness, and broad service temperature range (−260°C to 700–800 °C), positioning them as promising reinforcements for lightweight multifunctional structures. This review critically synthesizes recent advances in AM of BFRPCs, with particular emphasis on short- and continuous-fiber reinforcement in thermoplastic matrices. Material-extrusion-based processes are highlighted, wherein fiber orientation can be tailored from semi-random distributions to near-unidirectional architectures, enabling tensile strength enhancements approaching 200–300% alongside competitive flexural performance. Emerging developments involving recycled polymers, hybrid fiber architectures, and bi-matrix systems are systematically assessed. The potential of ultra-high-molecular-weight polyethylene (UHMWPE) as complementary toughening phase is examined, together with unresolved challenges associated with melt-viscosity mismatch and inadequate interfacial adhesion in AM. Key limitations including weak fiber-matrix adhesion, process-induced anisotropy, abrasive tool wear, and limited cross-platform compatibility are identified. The review concludes by outlining research priorities in interfacial engineering, formulation development, and process optimization for scalable, impact-resilient, and sustainable BFRPCs.