scholarly journals Generation of Wholly Thermoplastic Composites and Their Processing in Additive Manufacturing

2021 ◽  
Author(s):  
Tianran Chen ◽  
Donald Baid
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
High Performance ◽  
Liquid Crystalline ◽  
Mechanical Performance ◽  
Crystalline Polymer ◽  
Extrusion Process ◽  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Fused Filament Fabrication

3D printing has attracted great interest over the past three decades due to its high precision, less waste generation and design freedom[1-3]. One of the major challenges 3D printing is the poor mechanical performance of pure polymer parts. Researchers used traditional carbon and glass fiber reinforced composites to overcome this issue [4-7]. The traditional fibers can improve the mechanical properties of printed parts. However, the manufacturing techniques and printing process restrict the overall performance of the printed parts. Thermotropic liquid crystalline polymer (TLCP) is another reinforcement which offers lighter weight, lower viscosity, excellent mechanical performance and great recyclability [8-15]. TLCPs are capable of forming extended conformations when subjected to extensional or shear deformation.[16, 17] The formation of highly orientated molecular structure enables the generation of high mechanical properties . In this study, polyamide was reinforced with TLCP by the dual-extrusion technique to generate high performance composite filaments [18]. Rheological tests were used to optimize the processing conditions of the dual-extrusion process, which could minimize the degradation of matrix polymer. High performance and lightweight fiber-reinforced composite parts were fabricated by utilizing the fused filament fabrication (FFF) technique. The composite filaments were printed at the temperature below the melting point of TLCP to avoid the relaxation of TLCP. The mechanical performances of printed parts are greater than 3D printed parts which are reinforced by conventional fibers.

scholarly journals Generation of Wholly Thermoplastic Composites and Their Processing in Additive Manufacturing

2021 ◽  
Author(s):  
Tianran Chen
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
High Performance ◽  
Liquid Crystalline ◽  
Mechanical Performance ◽  
Crystalline Polymer ◽  
Extrusion Process ◽  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Fused Filament Fabrication

3D printing has attracted great interest over the past three decades due to its high precision, less waste generation and design freedom [1-3]. One of the major challenges 3D printing is the poor mechanical performance of pure polymer parts. Researchers used traditional carbon and glass fiber reinforced composites to overcome this issue [4-7]. The traditional fibers can improve the mechanical properties of printed parts. However, the manufacturing techniques and printing process restrict the overall performance of the printed parts. Thermotropic liquid crystalline polymer (TLCP) is another reinforcement which offers lighter weight, lower viscosity, excellent mechanical performance and great recyclability [8-15]. TLCPs are capable of forming extended conformations when subjected to extensional or shear deformation.[16, 17] The formation of highly orientated molecular structure enables the generation of high mechanical properties. In this study, polyamide was reinforced with TLCP by the dual-extrusion technique to generate high performance composite filaments [18]. Rheological tests were used to optimize the processing conditions of the dual-extrusion process, which could minimize the degradation of matrix polymer. High performance and lightweight fiber-reinforced composite parts were fabricated by utilizing the fused filament fabrication (FFF) technique. The composite filaments were printed at the temperature below the melting point of TLCP to avoid the relaxation of TLCP. The mechanical performances of printed parts are greater than 3D printed parts which are reinforced by conventional fibers.

Stiffness prediction of 3D printed fiber-reinforced thermoplastic composites

2019 ◽  
Vol 26 (3) ◽  
pp. 549-555
Author(s):  
Jin Young Choi ◽  
Mark Timothy Kortschot
Keyword(s):  
Mechanical Properties ◽  
Extrusion Direction ◽  
Analytical Models ◽  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Flat Plates ◽  
Fused Filament Fabrication ◽  
Element Analysis ◽  
Content Type ◽  
3D Printed

Purpose The purpose of this study is to confirm that the stiffness of fused filament fabrication (FFF) three-dimensionally (3D) printed fiber-reinforced thermoplastic (FRP) materials can be predicted using classical laminate theory (CLT), and to subsequently use the model to demonstrate its potential to improve the mechanical properties of FFF 3D printed parts intended for load-bearing applications. Design/methodology/approach The porosity and the fiber orientation in specimens printed with carbon fiber reinforced filament were calculated from micro-computed tomography (µCT) images. The infill portion of the sample was modeled using CLT, while the perimeter contour portion was modeled with a rule of mixtures (ROM) approach. Findings The µCT scan images showed that a low porosity of 0.7 ± 0.1% was achieved, and the fibers were highly oriented in the filament extrusion direction. CLT and ROM were effective analytical models to predict the elastic modulus and Poisson’s ratio of FFF 3D printed FRP laminates. Research limitations/implications In this study, the CLT model was only used to predict the properties of flat plates. Once the in-plane properties are known, however, they can be used in a finite element analysis to predict the behavior of plate and shell structures. Practical implications By controlling the raster orientation, the mechanical properties of a FFF part can be optimized for the intended application. Originality/value Before this study, CLT had not been validated for FFF 3D printed FRPs. CLT can be used to help designers tailor the raster pattern of each layer for specific stiffness requirements.

scholarly journals 3D Printing of Fibre-Reinforced Thermoplastic Composites Using Fused Filament Fabrication—A Review

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2188
Author(s):  
Andrew N. Dickson ◽  
Hisham M. Abourayana ◽  
Denis P. Dowling
Keyword(s):  
3D Printing ◽  
Polymer Composites ◽  
Mechanical Performance ◽  
Polymer Processing ◽  
Thermoplastic Composites ◽  
Fused Filament Fabrication ◽  
Compression Moulding ◽  
Processing Technologies ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer

Three-dimensional (3D) printing has been successfully applied for the fabrication of polymer components ranging from prototypes to final products. An issue, however, is that the resulting 3D printed parts exhibit inferior mechanical performance to parts fabricated using conventional polymer processing technologies, such as compression moulding. The addition of fibres and other materials into the polymer matrix to form a composite can yield a significant enhancement in the structural strength of printed polymer parts. This review focuses on the enhanced mechanical performance obtained through the printing of fibre-reinforced polymer composites, using the fused filament fabrication (FFF) 3D printing technique. The uses of both short and continuous fibre-reinforced polymer composites are reviewed. Finally, examples of some applications of FFF printed polymer composites using robotic processes are highlighted.

scholarly journals PEEK filament characteristics before and after extrusion within fused filament fabrication process

2022 ◽  
Author(s):  
Cleiton André Comelli ◽  
Richard Davies ◽  
HenkJan van der Pol ◽  
Oana Ghita
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Extrusion Process ◽  
X Ray Diffraction ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
Fast Scanning Calorimetry ◽  
Transmission Electron ◽  
Before And After ◽  
History Of

AbstractThe heating and extrusion process in fused filament fabrication (FFF) is significantly shorter than the conventional extrusion process where longer heating times and significant pressure are applied. For this reason, it is important to understand whether the crystal history of the feedstock is fully erased through the FFF process and whether the FFF process can be tailored further by engineering the crystallization of the feedstock filaments. In this context, a methodology for evaluating the influence of morphology and mechanical properties on different feedstock and extruded filaments is proposed. Filaments with three different PEEK 450G crystalline structures (standard crystallinity, drawn filament and amorphous filament) were selected and evaluated, before and after free extrusion. The resulting morphology, crystallinity and mechanical properties of the extruded filaments were compared against the feedstock properties. X-ray diffraction (XRD), transmission electron microscopy (TEM), differential and fast scanning calorimetry (DSC/FDSC) and tensile test were the techniques used to evaluate the materials. The results showed clear differences in the properties of the feedstock materials, while the analysis of the extruded filaments points to a homogenization of the resulting material producing mostly similar mechanical properties. However, the use of the drawn filament highlighted a statistically significant improvement in crystallinity and mechanical performance, especially in strain values. This conclusion suggests the innovative possibility of improving the quality of manufactured parts by tailoring the microstructure of the feedstock material used in the FFF process. Graphical abstract

Optimization of Design Process of Fused Filament Fabrication (FFF) 3D Printing

2018 ◽  
Author(s):  
Jaeyoon Kim ◽  
Bruce S. Kang
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
3D Printing ◽  
Design Process ◽  
Design Methodology ◽  
Tool Path ◽  
Fiber Reinforced ◽  
Fused Filament Fabrication ◽  
Principal Directions

Fused Filament Fabrication (FFF) is one of the most common Additive Manufacturing (AM) technologies for thermoplastic materials. PLA, ABS, and nylon have generally been used for prototype development. With the development of carbon fiber reinforced polymer (CFRP) filament for FFF, AM parts with improved strength and functionality can be realized. While mechanical properties of various CFRP have been well studied, design methodology for structural optimization of CFRP parts remains an active research area. In this paper, a systematic optimization of design process of FFF 3D printing methodology is proposed for CFRP. Starting with standard coupon specimen tests including tensile, bending, and creep tests to obtain mechanical properties of CFRP. Finite element analyses (FEA) are conducted to find principal directions of the AM part and computed principal directions are utilized as fiber orientations. Then, the connecting lines of principal directions are used to develop a customized tool-path in FFF 3D printing to extrude fibers aligned with principal directions. Since currently available infill-patterns in 3D printing cannot precisely draw customized lines, a specific tool-path algorithm has been developed to distribute fibers with the desired orientations. To predict/assess mechanical behavior of the AM part, 3D printing process was simulated followed by FEA to obtain the anisotropic structural behavior induced by the customized tool-path. To demonstrate the design/manufacturing methodology, spur gears of a ball milling machine were selected as a case study and carbon fiber reinforced nylon filament was chosen as the AM materials. Relevant compression tests were conducted to assess their performance compared with those printed at regular tool-path patterns. Preliminary results show that CFRP gear printed by customized tool-path has about 8% higher stiffness than those printed by regular patterns. Also, flow distribution of printed fibers was verified using scanning electron microscope (SEM). SEM images showed that approximately 91% of fibers were oriented as intended. In summary, assisted by FEA, a customized 3D printing tool-path for CFRP has been developed with a case study to verify the proposed AM design methodology.

Review of Mechanical Properties and Durability of PVA Fiber Reinforced Cement Based Composite Materials

2013 ◽  
Vol 804 ◽  
pp. 8-11 ◽  
Author(s):  
Xiao Bing Dai ◽  
Peng Zhang ◽  
Ji Xiang Gao
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
High Performance ◽  
Mechanical Performance ◽  
Construction Materials ◽  
Fiber Reinforced ◽  
Practical Engineering ◽  
Reinforced Cement ◽  
Pva Fiber ◽  
Structure Engineering

As a kind of high performance cement based construction materials, because of good mechanical performance and durability, PVA fiber reinforced cement based materials have been paid more and more attention in the field of civil structure engineering. To grasp the characteristics of PVA fiber reinforced cement based composite materials and promote a better application of PVA fiber reinforced cement based composite in practical engineering, a series of research works on the mechanical properties and durability of PVA fiber reinforced cement based composite were introduced systematically.

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