Improving mechanical properties of continuous fiber-reinforced thermoplastic composites produced by FDM 3D printer

2018 ◽  
Vol 38 (3) ◽  
pp. 99-116 ◽  
Author(s):  
Behnam Akhoundi ◽  
Amir Hossein Behravesh ◽  
Arvin Bagheri Saed

The main purpose of this research is to bolster mechanical properties of the parts, produced by an extrusion-based 3D printer, or fused deposition modeling machine, via increasing the content of continuous fiber yarn to its practical limit. In-melt continuous glass fiber yarn embedding was applied as a reliable and consistent method for simultaneous impregnation to produce continuous fiber-reinforced thermoplastic composites in the fused deposition modeling process. It is well known that the main weakness in the fused deposition modeling 3D printed products is their low strength compared to the manufactured ones by conventional methods such as injection molding and machining processes. This characteristic can be related to both inherent weakness of thermoplastic materials and poor adhesion between the deposited rasters and the layers. Although various attempts have been performed to tackle this issue, it is widely believed that using continuous fibers is the most effective method to serve this purpose if a reliable and consistent method is implemented. Since the mechanical properties of continuous fiber-reinforced composites directly depend on the content of fiber volume, maximizing the fiber content as well as producing an integrated part was assumed as the main objective. In this work, an analysis of various patterns of raster deposition was conducted, followed by the experiments and verification. The effective parameters on the fiber yarn volume, such as fiber yarn diameter, fiber yarn laying pattern, extrusion width, layer height, and flow percentage, were investigated and their optimal values were reported. The attained experimental results showed that, for polylactic acid-glass fiber yarn reinforced composite, with the extrusion width of 0.3 mm, the layer heights of 0.22 mm, flow percentage of 0.43, and the rectangular laying pattern, approximately 50% fiber-volume content can be achieved which resulted in tensile yield strength and modulus of 478 MPa and 29.4 GPa, respectively. There was an excellent agreement between these experimental results and predicted theoretically values by rule of mixture.

Author(s):  
Behnam Akhoundi ◽  
Amir Hossein Behravesh ◽  
Arvin Bagheri Saed

In this study, an innovative method was devised and implemented to produce continuous glass fiber–reinforced thermoplastic composites via a fused deposition modeling three-dimensional printer to enhance the mechanical properties of the printed products. In the extrusion-based, or filament-based, additive manufacturing process, namely, fused deposition modeling, the parts are basically formed via deposition of the material in the molten state, and thus embedding continuous fiber, in a solid form, is highly challenging. Hence, a nozzle system was designed and manufactured to feed the continuous fiber into the molten polymer simultaneously, which is called, here, in-melt simultaneous impregnation. With the presence of continuous fibers in the nozzle outlet, the feed of filament was calculatedly adjusted in the G-codes depending on the fiber volume percentage, to produce sound flow, and consistent deposition. Composite products were produced with various geometrical shapes. Via analysis and close control of the filament feeding, as a critical requirement to produce a sound printed product, composites with various fiber volume percentages were printed. Also, the mechanical properties of the printed parts with 30% by volume of glass fiber were measured. The results of the tensile test indicated that the continuous fibers were appropriately and effectively embedded that could result in remarkable increases in tensile strength and modulus of the samples, higher than 700%. The resulted values of tensile modulus were consistent with the values calculated via the rule of mixture. In addition, scanning electron microscopic images of the fracture sections suggest a sound adhesion between fibers and the matrix.


2019 ◽  
Vol 7 (4) ◽  
Author(s):  
Zhihui Liu ◽  
Yachao Wang ◽  
Jing Shi

Abstract Fused deposition modeling (FDM) printing of continuous fiber reinforced polymers had been a challenge until about 5 years ago. With the reinforcement of continuous fiber, the mechanical properties of FDM printed polymers are improved by leaps and bounds. In this paper, we aim to investigate the possibility of further improvement in the mechanical properties of three-dimensional (3D) printed continuous fiber reinforced polymers by adding nanoreinforcements to the polymer matrix. Kevlar fiber is selected as the continuous fiber reinforcement, nylon 6 (PA 6) is selected as the polymer matrix material, and carbon nanotubes (CNTs) or graphene nanoplatelets (GNPs) nanoparticles are selected as the nanoreinforcements. In the experiment, CNT or GNP nanoparticles are first mixed with nylon 6 pellets to make nanocomposites, the nanocomposites are then extruded into filaments for 3D printing, and finally, both Kevlar filament and nanocomposite filament are fed through the printing nozzle and deposited on the platform. Tensile specimens are directly printed from pure PA 6 and three types of nanocomposites, namely, CNT/PA 6, GNP/PA 6, and GNP-NH2/PA 6, as well as Kevlar fiber reinforced PA 6 and three types of Kevlar fiber reinforced nanocomposites. The results indicate that although Kevlar fibers dominate the enhancement of mechanical properties for the printed composite materials, the existence of GNP nanofillers also provide a noticeable contribution to the enhancement of tensile strengths and moduli, while the effect of CNTs is much less pronounced.


Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 976 ◽  
Author(s):  
Teng-Chun Yang

Wood fiber-reinforced polylactic acid (PLA) composites (WFRPCs) were used as a filament to manufacture the unidirectional WFRPC components by means of fused deposition modeling (FDM). The physico-mechanical properties of the WFRPC components printed at different extrusion temperatures (200, 210, 220, and 230 °C) were determined. The results revealed that most of the physical properties (moisture content, surface roughness, water absorption rate, and thickness swelling rate) of the printed WFRPC component were not significantly influenced by extrusion temperature, while its density and color difference increased as the extrusion temperature increased. Additionally, the tensile and flexural properties of the FDM-printed WFRPC component decreased when the extrusion temperature was more than 200 °C, whereas the compressive strength and internal bond strength increased by 15.1% and 24.3%, respectively, when the extrusion temperature was increased from 200 to 230 °C. Furthermore, scanning electronic microscopy (SEM) demonstrated that the fracture surface of the tensile component printed at a higher extrusion temperature exhibited a better compatibility at fiber/PLA interfaces and good adhesion between the extruded filament segments. These results indicate that the FDM printing process using different extrusion temperatures has a substantial impact on the surface color, density, and mechanical properties of the printed WFRPC component.


Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4520
Author(s):  
Salman Pervaiz ◽  
Taimur Ali Qureshi ◽  
Ghanim Kashwani ◽  
Sathish Kannan

Composite materials are a combination of two or more types of materials used to enhance the mechanical and structural properties of engineering products. When fibers are mixed in the polymeric matrix, the composite material is known as fiber-reinforced polymer (FRP). FRP materials are widely used in structural applications related to defense, automotive, aerospace, and sports-based industries. These materials are used in producing lightweight components with high tensile strength and rigidity. The fiber component in fiber-reinforced polymers provides the desired strength-to-weight ratio; however, the polymer portion costs less, and the process of making the matrix is quite straightforward. There is a high demand in industrial sectors, such as defense and military, aerospace, automotive, biomedical and sports, to manufacture these fiber-reinforced polymers using 3D printing and additive manufacturing technologies. FRP composites are used in diversified applications such as military vehicles, shelters, war fighting safety equipment, fighter aircrafts, naval ships, and submarine structures. Techniques to fabricate composite materials, degrade the weight-to-strength ratio and the tensile strength of the components, and they can play a critical role towards the service life of the components. Fused deposition modeling (FDM) is a technique for 3D printing that allows layered fabrication of parts using thermoplastic composites. Complex shape and geometry with enhanced mechanical properties can be obtained using this technique. This paper highlights the limitations in the development of FRPs and challenges associated with their mechanical properties. The future prospects of carbon fiber (CF) and polymeric matrixes are also mentioned in this study. The study also highlights different areas requiring further investigation in FDM-assisted 3D printing. The available literature on FRP composites is focused only on describing the properties of the product and the potential applications for it. It has been observed that scientific knowledge has gaps when it comes to predicting the performance of FRP composite parts fabricated under 3D printing (FDM) techniques. The mechanical properties of 3D-printed FRPs were studied so that a correlation between the 3D printing method could be established. This review paper will be helpful for researchers, scientists, manufacturers, etc., working in the area of FDM-assisted 3D printing of FRPs.


Author(s):  
Pravin R. Kubade ◽  
Hrushikesh B. Kulkarni ◽  
Vinayak C. Gavali

Additive Manufacturing or three-dimensional printing refers to a process of building lighter, stronger three-dimensional parts, manufactured layer by layer. Additive manufacturing uses a computer and CAD software which passes the program to the printer to build the desired shape. Metals, thermoplastic polymers, and ceramics are the preferred materials used for additive manufacturing. Fused deposition modeling is one additive manufacturing technique involving the use of thermoplastic polymer for creating desired shape. Carbon fibers can be added into polymer to strengthen the composite without adding additional weight. Present work deals with the manufacturing of Carbon fiber-reinforced Polylactic Acid composites prepared using fused deposition modeling. Mechanical and thermo-mechanical properties of composites are studied as per ASTM standards and using sophisticated instruments. It is observed that there is enhancement in thermo-mechanical properties of composites due to addition reinforcement which is discussed in detail.


2021 ◽  
Author(s):  
Faraz Safari ◽  
Abdolvahed Kami ◽  
Vahid Abedini

The main objective of this study is to review existing research on the application of fused deposition modeling (FDM) for 3D printing of continuous fiber reinforced composites (CFRCs). An overview of additive manufacturing (AM) technology production techniques is provided first, followed by a look into FDM technology. The articles on CFRC printing were then summarized. The type of reinforcing material and matrix utilized, the research subject, the mechanical properties investigated, and the sample dimensions are all listed. Various pre-processing, processing, and post-processing conditions, as well as their impact on CFRC mechanical properties, were also discussed.


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