A critical review of the past, present, and future of 3D printing for continuous and short fiber composites

Abstract

This review critically examines recent advancements in 3D printing of short fiber-reinforced polymer composites (SFRCs) and continuous fiber-reinforced polymer composites (CFRCs), emphasizing their potential to transform industrial applications through enhanced mechanical performance, multifunctionality, and sustainability. It analyzes the evolution of additive manufacturing methods, material innovations-including bio-based polymers, recycled fibers, and nanofiber-reinforced systems-and their impact on tensile, shear, flexural, toughness and energy absorption behavior. While notable progress has been achieved, persistent challenges remain, such as limited fiber alignment control, inadequate interfacial bonding, and porosity-induced mechanical degradation. The review highlights contradictions in reported mechanical improvements versus practical printability, and identifies gaps in scalable integration of continuous fibers, standardized testing protocols, and predictive process models. Recent innovations-such as in-situ sensing, multi-material printing, and AI-driven optimization-show promise but lack industrial maturity and real-time adaptability. Furthermore, despite growing interest in sustainable materials, inconsistency in bio-fiber performance and limited recyclability frameworks constrain broader adoption. This review not only synthesizes the current state-of-the-art but also outlines critical limitations and unresolved issues, providing a roadmap for future research toward structurally robust, scalable, and environmentally responsible fiber-reinforced polymer composites (FRPC) based additive manufacturing.