Additive Manufacturing of Carbon Fiber Reinforced Epoxy Thermoset with Improved Thermomechanical Properties (original) (raw)
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Journal of Manufacturing and Materials Processing
This work presents an innovative system that allows the oriented deposition of continuous fibers or long fibers, pre-impregnated or not, in a thermoplastic matrix. This system is used in an integrated way with the filamentary fusion additive manufacturing technology and allows a localized and oriented reinforcement of polymer components for advanced engineering applications at a low cost. To demonstrate the capabilities of the developed system, composite components of thermoplastic matrix (polyamide) reinforced with pre-impregnated long carbon fiber (carbon + polyamide), 1 K and 3 K, were processed and their tensile and flexural strength evaluated. It was demonstrated that the tensile strength value depends on the density of carbon fibers present in the composite, and that with the passage of 2 to 4 layers of fibers, an increase in breaking strength was obtained of about 366% and 325% for the 3 K and 1 K yarns, respectively. The increase of the fiber yarn diameter leads to higher va...
Materials
3D printing allows controlled deposition of composite components, which the user defines by the modification of the printing parameters. The article demonstrates that all observed printing parameters (infill type, infill orientation) influence the tensile test results of nylon reinforced with chopped carbon fiber. The highest tensile strength obtains specimens with the maximum number of walls around the circumference. The plastic region of the tensile diagram differs significantly with the change of material orientation in the structure, as the specimens with material deposited 45/−45 to the load axis have four times greater tensile strains and 20% higher tensile stresses than 0/90. The assessment of results reveals the significant difference between deformations at break and permanent deformations. In addition, the permanent lateral strain reaches up to 20%. Finally, the article consists of a brief assessment of the printing parameters (printing time, weight) of individual series. ...
Fused deposition modelling (FDM) is widely used method to fabricate thermoplastic parts, which are mainly used as rapid prototypes for functional testing with advantages of minimal wastage, and ease of material change. Due to the intrinsically limited mechanical properties of pure thermoplastic materials, there is a critical need to improve mechanical properties for FDM-fabricated pure thermoplastic parts. One of the possible methods is adding reinforced materials (such as carbon fibers) into plastic materials to form thermoplastic matrix carbon fiber reinforced plastic (CFRP) composites those could be directly used in the actual application areas, such as aerospace, automotive, and wind energy. The current study is focused to take a look of the work done in the area of 3D printing with thermoplastic material and carbon fiber reinforced thermoplastic material. The study is attempting to take an overview of reinforcement of different materials into thermoplastic in different ways. The effect of reinforcement of carbon fiber into thermoplastic can be studied by using different mechanical and thermo mechanical tests. The effects of different fiber orientation on mechanical properties, effect on infill speed, and nozzle temperature and layer thickness on tensile properties are also studied. This paper reviews work related to investigation of mechanical and thermo mechanical properties of carbon fibre reinforced thermoplastic composite fabricated using fused deposition modelling (FDM).
Additive manufacturing (AM) technologies have been successfully applied in various applications. Fused deposition modeling (FDM), one of the most popular AM techniques, is the most widely used method for fabricating thermoplastic parts those are mainly used as rapid prototypes for functional testing with advantages of low cost, minimal wastage, and ease of material change. Due to the intrinsically limited mechanical properties of pure thermoplastic materials, there is a critical need to improve mechanical properties for FDM-fabricated pure thermoplastic parts. One of the possible methods is adding reinforced materials (such as carbon fibers) into plastic materials to form thermoplastic matrix carbon fiber reinforced plastic (CFRP) composites those could be directly used in the actual application areas, such as aerospace, automotive, and wind energy. This paper is going to present FDM of thermoplastic matrix CFRP composites and test if adding carbon fiber (different content and length) can improve the mechanical properties of FDM-fabricated parts. The CFRP feedstock filaments were fabricated from plastic pellets and carbon fiber powders for FDM process. After FDM fabrication, effects on the tensile properties (including tensile strength, Young's modulus, toughness, yield strength, and ductility) and flexural properties (including flexural stress, flexural modulus, flexural toughness, and flexural yield strength) of specimens were experimentally investigated. In order to explore the parts fracture reasons during tensile and flexural tests, fracture interface of CFRP composite specimens after tensile testing and flexural testing was observed and analyzed using SEM micrograph.
Polymers
The increasing use of carbon fiber and epoxy resin composite materials yields an increase in the amount of waste. Therefore, we present a solution consisting of composites manufactured by hot pressing, employing polyamides (either PA11 or PA12) and a mechanically recycled carbon fiber-reinforced polymer (CFRP) as reinforcement. The main objectives are to study the manufacturing of those composites, to evaluate the fiber distribution, and to perform a mechanical, dynamical, and thermomechanical characterizations. The X-ray micro-computed tomography (μCT) shows that the fibers are well-distributed, maintaining a homogeneous fiber volume fraction across the material. The variability in the results is typical of discontinuous fiber composites in which the fibers, although oriented, are not as homogeneously distributed as in a continuous fiber composite. The mechanical and dynamic properties barely differ between the two sets of composites. A dynamic-mechanical analysis revealed that the...
Mechanical Properties of Printed Epoxy-Carbon Fiber Composites
Experimental Mechanics, 2019
Despite the promise of additive manufacturing (AM) to bring unprecedented agility and design freedom to manufactured components, structural applications remain largely out of reach due to material restrictionsnotably the lack of a mature AM process for reinforced thermoset composites. AM is also hindered by process-induced defects such as porosity and unfavorable microstructure. This research shows that a direct write AM process for epoxy / chopped carbon fiber composites can simultaneously achieve a high degree of fiber alignment and low degree of porosity, obtaining 90% of the theoretical tensile modulus and 66% of the theoretical tensile strength for a fully aligned composite. These values exceed those of compression molded properties for the same material. Transverse properties of AM samples were roughly half of the longitudinal properties but showed no statistically significant difference from the matrix material, suggesting that the process may not adversely affect microstructure. The addition of only 5.5 vol% carbon fiber more than doubled the strength and stiffness of the neat epoxy, and more than tripled the properties of ABS thermoplastic while achieving a higher glass transition temperature. Flexural properties show similar trends. SEM and CT imaging shows that fiber orientation is largely maintained in the print direction and cross-section micrographs show there is sufficient local material flow during deposition to achieve low porosity.
Nowadays, additive manufacturing is being used in various industries such as automotive, aviation and space, medical applications, etc. Although additive manufacturing methods offer more freedom in design and manufacturing, they usually have low production speed and mechanical properties. Continuous carbon fiber reinforced thermoplastic (CFRTP) composites are one of the investigated methods in the literature to increase the mechanical properties of the additively manufactured parts. This study utilized a production line based upon the melt impregnation method to obtain continuous carbon fiber reinforced thermoplastic filaments using polyamide and continuous carbon fibers. In the printing process, an infrared heat source was utilized to further increase the mechanical properties by improving the interlaminar bonding. The mechanical properties of the printed parts were measured using three-point bending tests. A significant increase was observed in flexural modulus of elasticity and flexural strength with infrared heaters at low printing speeds. A maximum value of 418.99 MPa flexural strength and 52.15 GPa flexural modulus was achieved.
Polymers, 2021
Carbon fiber-reinforced polymers are considered a promising composite for many industrial applications including in the automation, renewable energy, and aerospace industries. They exhibit exceptional properties such as a high strength-to-weight ratio and high wear resistance and stiffness, which give them an advantage over other conventional materials such as metals. Various polymers can be used as matrices such as thermosetting, thermoplastic, and elastomers polymers. This comprehensive review focuses on carbon fiber-reinforced thermoplastic polymers due to the advantages of thermoplastic compared to thermosetting and elastomer polymers. These advantages include recyclability, ease of processability, flexibility, and shorter production time. The related properties such as strength, modulus, thermal conductivity, and stability, as well as electrical conductivity, are discussed in depth. Additionally, the modification techniques of the surface of carbon fiber, including the chemical...
Journal of Composites Science
The most common method to fabricate both simple and complex structures in the additive manufacturing process is fused deposition modeling (FDM). Many researchers have studied the strengthening of FDM components by adding short carbon fibers (CF) or by reinforcing solid carbon fiber rods. In the current research, we sought to enhance the mechanical properties of FDM components by adding bioinspired solid CF rods during the fabrication process. An effective bonding interface of bioinspired CF rods and polylactic acid (PLA) was achieved by triangular interlocking sutures and by employing synthetic glue as the binding agent. In particular, the tensile strength of solid CF rod reinforced PLA samples was studied. Critical parameters such as layer thickness, extruder temperature, extruder speed, and shell thickness were considered for optimization. Significant process parameters were identified through leverage plots using the response surface methodology (RSM). The optimum parameters were...
REVIEWS ON ADVANCED MATERIALS SCIENCE
The scarcity of nonrenewable resource motivated inclination towards the environmental-friendly novel materials and development of waste natural filler-based hybrid composite is encouraged to fulfill the material demand. Epoxy resins-based composites are high-performing thermosetting polymers and have outstanding blending properties, good machinability, and low cost. Due to these advantages, thermoset plastic is largely used in a broad range of engineering applications; however, thermomechanical properties of neat epoxy are low. Thus, to enhance the thermomechanical properties of epoxy, it is interfaced materials such as graphite, graphene nanoplatelet, boron, carbon fiber, aluminium, silver, etc. Among various substances, graphene has been deliberated as an acceptable novel filler because of its exceptional properties. In addition to inorganic filler inclusion, natural filler/fiber like hemp, sisal, flax, bamboo, jute, etc. can be utilized in a higher percentage as biodegradable mat...