FDM Based 3D Printing of Short Fiber Composites: A Comparative Review of Synthetic and Natural Fiber Composites

Abstract

Short fiber-reinforced composites produced through fused deposition modeling (FDM) have emerged as promising materials for improving the performance of additively manufactured polymer components. While conventional thermoplastics offer design flexibility and processability, their relatively low stiffness, weak interlayer bonding, and anisotropic behavior limit their use in demanding applications. Incorporating short fibers into thermoplastic matrices has therefore gained attention as an effective strategy to enhance the mechanical, thermal, and functional properties of FDM-printed parts. This review provides a comprehensive comparative analysis of natural and synthetic short fiber-reinforced composites used in FDM-based additive manufacturing. It examines how fiber characteristics including type, morphology, aspect ratio, and fiber matrix interactions influence mechanical performance, thermal stability, and chemical resistance. Key processing challenges such as changes in melt rheology, fiber breakage during extrusion, anisotropy, interlayer adhesion limitations, porosity formation, and dimensional accuracy are also discussed. Environmental aspects including life cycle impacts, recyclability, moisture sensitivity, and durability are considered. Natural fibers offer advantages in renewability, lower density, and reduced embodied energy, while synthetic fibers such as carbon and glass provide superior mechanical performance and thermal stability for structural applications. Hybrid reinforcement strategies combining natural and synthetic fibers are also highlighted as a promising approach to balance performance and sustainability. Finally, key research gaps and future directions are identified to support the development of more reliable and sustainable FDM composite systems. This integrated perspective aims to guide material selection and process optimization for next-generation fiber-reinforced additive manufacturing.