In the last few years, utilizing fiber reinforced additive manufacturing (FRAM)-based components in several industries has become quite popular. Compared to conventional AM technologies, FRAM offered complementary solutions to their needs. In general, fibers have been traditionally used in many manufacturing processes for various reasons. However, using conventional methods, there are obstacles in obtaining the desired complex geometries and low setup costs. AM offers possible avoidance of these limitations. Shape complexity, infill density, and manufacturing lead times are no longer barriers. Bridging AM with fiber reinforced materials offers a vast opportunity for lightweight and strong parts. Depending on the affinity, fibers with different structures can be mixed with different matrix materials and, thus, create stronger parts with improved mechanical properties. Process parameters like raster angle, infill speed, layer thickness, and nozzle temperature also strongly impact physical properties of FRAM products and are considered carefully. FRAM-based components are used in many industries such as aerospace, motorsports, and biomedicine, where the weight, strength, and complexity of parts are critical. Hence, numerous industrial companies and research facilities are investigating the implementation and adaptation of FRAM to their requirements. Studies are generally conducted on new materials, new FRAM technologies, the effect of fiber orientations and fraction on the performance of parts, improving the printing parameters, and other subjects. This study reports the current trends and challenges that FRAM is bringing to AM ecosystem.

The trends and challenges of fiber reinforced additive manufacturing

Fiber reinforced composites offer exceptional directional mechanical properties, and combining their advantages with the capability of 3D printing has resulted in many innovative research fronts. This review aims to summarize the methods and findings of research conducted on 3D-printed carbon fiber reinforced composites. The review is focused on commercially available printers and filaments, as their results are reproducible and the findings can be applied to functional parts. As the process parameters can be readily changed in preparation of a 3D-printed part, it has been the focus of many studies. In addition to typical composite driving factors such as fiber orientation, fiber volume fraction and stacking sequence, printing parameters such as infill density, infill pattern, nozzle speed, layer thickness, built orientation, nozzle and bed temperatures have shown to influence mechanical properties. Due to the unique advantages of 3D printing, in addition to conventional unidirectional fiber orientation, concentric fiber rings have been used to optimize the mechanical performance of a part. This review surveys the literature in 3D printing of chopped and continuous carbon fiber composites to provide a reference for the state-of-the-art efforts, existing limitations and new research frontiers.

3D-Printed Carbon Fiber Reinforced Polymer Composites: A Systematic Review

Biomimetic armour design strategies for additive manufacturing: a review

Fused deposition modelling (FDM) is a widely used additive layer manufacturing process that deposits thermoplastic material layer-by-layer to produce complex geometries within a short time. Increasingly, fibres are being used to reinforce thermoplastic filaments to improve mechanical performance. This paper reviews the available literature on fibre reinforced FDM to investigate how the mechanical, physical, and thermal properties of 3D-printed fibre reinforced thermoplastic composite materials are affected by printing parameters (e.g., printing speed, temperature, building principle, etc.) and constitutive materials properties, i.e., polymeric matrices, reinforcements, and additional materials. In particular, the reinforcement fibres are categorized in this review considering the different available types (e.g., carbon, glass, aramid, and natural), and obtainable architectures divided accordingly to the fibre length (nano, short, and continuous). The review attempts to distil the optimum processing parameters that could be deduced from across different studies by presenting graphically the relationship between process parameters and properties. This publication benefits the material developer who is investigating the process parameters to optimize the printing parameters of novel materials or looking for a good constituent combination to produce composite FDM filaments, thus helping to reduce material wastage and experimental time.

Fused Deposition Modelling of Fibre Reinforced Polymer Composites: A Parametric Review

Additive manufacturing (AM) is a potential engineering technique that could be used in various applications owing to its greatest advantages like flexibility in design, least expensive, versatile material synthesis and low material wastage. From various studies, it was understood that the mechanical performance of fiber-reinforced polymer composite materials (FRPCs) manufactured by AM was influenced by the process parameters to a certain extent. Additionally, numerous studies stated that the strength characteristics of the additively manufactured samples from continuous fibers, like carbon and glass, were high when compared with the samples reinforced with short fibers. Various earlier reviews enunciated that the increase in fiber volume fraction increased the strength and stiffness of the AM components many a times, while the mechanical characteristics of the samples also faced a significant increment due to the addition of fibers. Current work focuses on the influence of process parameters like process of 3D printing, materials used, layer thickness and so on upon the properties of additively manufactured FRPCs. Primary focus of the current study is to determine the effect of factors like thickness of the layer, content of the fiber in volume and the build orientation upon the properties of FRPC components manufactured by AM. This study also outlines the influence of some other parameters like loads applied, environment and analysis models on the properties of AM components along with their merits and demerits.

https://link.springer.com/content/pdf/10.1007/s11665-021-05832-y.pdf

Influence of Process Parameters on the Properties of Additively Manufactured Fiber-Reinforced Polymer Composite Materials: A Review

Fused Filament Fabrication (FFF), classified under material extrusion additive manufacturing technologies, is a widely used method for fabricating thermoplastic parts with high geometrical complexity. To improve the mechanical properties of pure thermoplastic materials, the polymeric matrix may be reinforced by different materials such as carbon fibers. FFF is an advantageous process for producing polymer matrix composites because of its low cost of investment, high speed and simplicity as well as the possibility to use multiple nozzles with different materials. In this study, the aim was to investigate the dimensional accuracy and mechanical properties of chopped carbon-fiber-reinforced tough nylon produced by the FFF process. The dimensional accuracy and manufacturability limits of the process are evaluated using benchmark geometries as well as process-inherent effects like stair-stepping effect. The hardness and tensile properties of produced specimens in comparison to tough nylon without any reinforcement, as well as continuous carbon-reinforced specimens, were presented by taking different build directions and various infill ratios. The fracture surfaces of tensile specimens were observed using a Scanning Electron Microscope (SEM). The test results showed that there was a severe level of anisotropy in the mechanical properties, especially the modulus of elasticity, due to the insufficient fusion between deposited layers in the build direction. Moreover, continuous carbon-reinforced specimens exhibited very high levels of tensile strength and modulus of elasticity whereas the highest elongation was achieved by tough nylon without reinforcement. The failure mechanisms were found to be inter-layer porosity between successive tracks, as well as fiber pull out.

Dimensional Accuracy and Mechanical Properties of Chopped Carbon Reinforced Polymers Produced by Material Extrusion Additive Manufacturing.

Due to the developments and the interest of leading aerospace companies, additive manufacturing (AM) has become a highly discussed topic in the last decades. This is mainly due to its capability of producing parts with high geometrical complexity, short manufacturing lead times, and suitability for customization as well as for low-volume production. As is the case with aircraft fuselage body where weight reduction while keeping the demanding mechanical properties is of uttermost importance, modern technology applications sometimes need materials with unusual combinations of properties that cannot be solely provided by metals, polymers, or ceramics. In this case, composite materials combining two or more materials allow having the preferred properties in one material. Thus, AM of composites is becoming more and more important for critical applications. Fiber reinforcement can significantly enhance the properties of resins/polymeric matrix materials. Although continuous fiber composites even present higher mechanical performance, the manufacturing methods for chopped fibers are more commercially available. This chapter reviews the studies in the field involving many aspects spanning from design, process technology, and applications to available equipment.

/pdf/additive-manufacturing-of-polymer-matrix-composites-1uia2gz5n6.pdf

Additive Manufacturing of Polymer Matrix Composites

Hybrid metal additive manufacturing is a novel way of combining the advantages of different manufacturing methods. It offers the freedom of fabricating functional parts with varying requirements such as size and complexity, overcoming the need for additional joining operations. On the other hand, combining dissimilar materials enables the route for obtaining different properties such as mechanical strength, high temperature and corrosion resistance in a single part body. In this study, wire arc additive manufacturing (WAAM) and laser powder bed fusion (L-PBF) technologies were combined utilizing dissimilar metals for each process. Deposition of AISI 316L stainless steel on previously L-PBF manufactured 17-4 PH stainless steel part was successfully executed using WAAM process. Microstructural observations showed five different zones in the as-built state whereas a uniform microstructure was obtained following the heat treatment as confirmed by hardness measurements. Tensile tests were conducted on the specimens extracted from the L-PBF/WAAM interface and the results showed a ductile fracture from the WAAM region, validating the strength of the interface. The tensile test results exceeded the standard strength requirements with a minor decrease in ductility.

Microstructure and mechanical properties of hybrid additive manufactured dissimilar 17-4 PH and 316L stainless steels

Pulsed-mode Selective Laser Melting of 17-4 PH stainless steel: Effect of laser parameters on density and mechanical properties

Combining the geometrical freedom provided by laser powder bed fusion (L-PBF), a powder bed fusion additive manufacturing (AM) process, and tailoring the mechanical properties by the use of lattice structures, many applications benefit from lightweight lattice structures such as aerospace and biomedical. Many different aspects of the lattice structures produced by L-PBF have been addressed in the literature including weight reduction, energy damping, compression behavior, manufacturability, and surface characteristics. Although lattices are seen as a promising design tool, the influence of using lattices inside the part surface on the wear behavior of L-PBF specimens has not yet been addressed in the literature. In this study, the effect of different lattice structures varying in unit cell geometry and size, built along different directions on the wear behavior, is addressed using AISI 316L powder processed with L-PBF. Moreover, to understand the wear behavior in detail, microhardness and compression testing of the samples were accomplished. As a result, it is found that the microhardness measurements change by only 5% on different build directions, whereas the lattice type is a significant factor regarding the modulus of elasticity and absorbed energy per unit volume. Moreover, it is concluded that although the coefficient of friction has an average value of 0.7, it does not vary depending on the tested factors, whereas the specific wear rate is influenced by the build direction and part geometry. Thus, for applications where tribological properties are important, the effect of heat dissipation and cooling rate leading to microstructural changes needs to be considered when utilizing L-PBF.

Evren Yasa

Papers

Dimensional Accuracy and Mechanical Properties of Chopped Carbon Reinforced Polymers Produced by Material Extrusion Additive Manufacturing.

Additive Manufacturing of Polymer Matrix Composites

Microstructure and mechanical properties of hybrid additive manufactured dissimilar 17-4 PH and 316L stainless steels

Pulsed-mode Selective Laser Melting of 17-4 PH stainless steel: Effect of laser parameters on density and mechanical properties

Tribological and mechanical behavior of AISI 316L lattice-supported structures produced by laser powder bed fusion