Fused deposition modeling (FDM) is a three-dimensional (3D) printing process that uses thermoplastic polymer feedstock. This technology can be used with a wide range of raw materials and provides the potential for customized or personalized manufacturing at low cost. Although the quality of FDM parts has been improved in recent years by continuous optimization of the preparation and printing processes, the products tend to have low mechanical strength owing to the layered nature of the components. The use of fiber-reinforced composites with a thermoplastic matrix can improve the tensile strength and tensile modulus of FDM parts, owing to their high specific strength and high specific modulus. The mechanical properties of fiber-reinforced thermoplastic composites produced by FDM are dependent on a series of complex phenomena such as material flow, fiber orientation, filament/layer bonding, heat conduction, and residual stress. Analysis of the inherent correlation of the above phenomena is key to promoting the application and development of composite FDM technology. Therefore, many researchers have aimed to identify appropriate fiber reinforcement materials and optimize the preparation process in recent years. Both short and continuous fibers are commonly used to form composite materials for the FDM technique. FDM with short fiber composites was developed first, as the preparation process is relatively simple. However, continuous fiber composites tend to have superior mechanical properties. Based on key factors such as the preparation process, material properties, and molding mechanism, researchers have focused on the in-fluence of process parameters such as fiber content, deposition angle, printing speed, nozzle temperature, layer thickness, and chemical additives on the mechanical properties of the molded fiber-reinforced composite parts. These studies provide the possibility of producing higher-quality 3D-printed and molded parts with superior mechanical properties by taking full advantage of fiber-reinforced materials. This article reviews recent advances in FDM fiber reinforced composites. The mechanical properties of short fiber and continuous fiber-reinforced composites and the influence of process parameters on mechanical properties are introduced according to the FDM molding principle and the research status of FDM fiber-reinforced composite materials. In addition, the basic scientific problems and key technical problems that still need to be solved are summarized, and possible future research directions are indicated. © 2021, Materials Review Magazine. All right reserved.
