scholarly journals Development of an Additive Manufacturing System for the Deposition of Thermoplastics Impregnated with Carbon Fibers

2019 ◽  
Vol 3 (2) ◽  
pp. 35 ◽  
Author(s):  
Miguel Reis Silva ◽  
António M. Pereira ◽  
Nuno Alves ◽  
Gonçalo Mateus ◽  
Artur Mateus ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Additive Manufacturing ◽  
Carbon Fibers ◽  
Low Cost ◽  
Deposition Process ◽  
Processing Parameters ◽  
Yarn Diameter ◽  
Thermoplastic Matrix ◽  
Anisotropic Mechanical Properties ◽  
Long Carbon Fiber

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 values of tensile strength of the composite. The obtained standard deviation reveals that the deposition process gives rise to components with anisotropic mechanical properties and the need to optimize the processing parameters, especially those that lead to an increase in adhesion between deposited layers.

scholarly journals Адитивне формування вуглекомпозитів на основі L-полілактиду

2020 ◽  
Vol 140 (6) ◽  
pp. 104-111
Author(s):  
Р. Ш. Іскандаров ◽  
Н. В. Сова ◽  
Б. М. Савченко ◽  
І. І. П'ятничук ◽  
В. А. Татаренко
Keyword(s):  
Tensile Strength ◽  
Additive Manufacturing ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Polymer Matrix ◽  
Fiber Composites ◽  
Carbon Composite ◽  
Test Method ◽  
Carbon Fiber Composites ◽  
Injection Molded

Study of the FFF additive manufacturing process of composite material based on L – polylactide (PLLA) with ultra-short carbon fibers. Tensile strength and elongation at break for all test specimens were determined according to ISO 527. Tensile modulus - ASTM D638-10, specimen density - PN-EN ISO 1183, microscopic examination - according to ASTM E2015 - 04 (2014). Charpy Shock Tests ISO 179 and ASTM D256. Bending test method ISO 178 and ASTM D 790. The rational modes of FFF additive manufacturing (AM) of carbon fiber composite based on PLLA was established. Properties of carbon fiber PLLA and unfilled PLLA was determinated for AM formed samples and injection molded samples. Carbon fiber composites have significantly higher flexural and tensile module us values compared to the original L-polylactide, which is due to the effect of polymer matrix reinforcement by the fibrous component. However, finished products obtained by AM PLLA carbon composite have a lower impact strength and tensile strength, which is likely to be due to the fact that the carbon fibers are short (50-60 mkm) and have a cavitations effect during injection molding and AM. Density of carbon fiber filled PLLLA was lower the theoretically calculated value for filament material as well for injection molded and AM formed samples. Density reduction probably the main cause of impact properties deterioration due to cavity forming around carbon fibers. Density and tensile properties of AM formed samples can be changed by AM slicing parameter – extrusion multiplier. Cavitation effect for carbon fiber composites observed for PLLA composite in form AM filament, injection molded parts and AM formed samples. Cavity forming was confirmed by optical microscopy and density measurement. Possible reason for cavity forming is orientation deformation of the fiber in polymer matrix during the formation of the filament. The effect of cavitation also persists in the AM of products from carbon composites due to the passage of the orientation at the exit of the printer nozzle.  The possibility of regulating the density and physical and mechanical properties of carbon composite products obtained by the additive manufacturing method has been established. Selection of rational values of the extrusion multiplier and the direction of the layers in the additive molding allows you to create products with the desired complex of properties.

scholarly journals Interface Behavior and Interface Tensile Strength of a Hardened Concrete Mixture with a Coarse Aggregate for Additive Manufacturing

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5147
Author(s):  
Arnošt Vespalec ◽  
Josef Novák ◽  
Alena Kohoutková ◽  
Petr Vosynek ◽  
Jan Podroužek ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Additive Manufacturing ◽  
Pore Size ◽  
Coarse Aggregate ◽  
Deposition Process ◽  
Interface Strength ◽  
Concrete Mixture ◽  
Hardened Concrete ◽  
Time Intervals ◽  
Layer Interface

3D concrete printing technology (3DCP) is a relatively new technology that was first established in the 1990s. The main weakness of the technology is the interface strength between the extruded layers, which are deposited at different time intervals. Consequently, the interface strength is assumed to vary in relation to the time of concrete casting. The proposed experimental study investigated the behavior of a hardened concrete mixture containing coarse aggregates that were up to 8 mm in size, which is rather unusual for 3DCP technology. The resulting direct tensile strength at the layer interface was investigated for various time intervals of deposition from the initial mixing of concrete components. To better understand the material behavior at the layer interface area, computed tomography (CT) scanning was conducted, where the volumetric and area analysis enabled validation of the pore size and count distribution in accordance with the layer deposition process. The analyzed CT data related the macroscopic anisotropy and the resulting crack pattern to the temporal and spatial variability that is inherent to the additive manufacturing process at construction scales while providing additional insights into the porosity formation during the extrusion of the cementitious composite. The observed results contribute to previous investigations in this field by demonstrating the causal relationships, namely, how the interface strength development is determined by time, deposition process, and pore size distribution. Moreover, in regard to the printability of the proposed coarse aggregate mixture, the specific time interval is presented and its interplay with interface roughness and porosity is discussed.

scholarly journals Wire Arc Additive and High-Temperature Subtractive Manufacturing of Ti-6Al-4V

2021 ◽  
Vol 11 (20) ◽  
pp. 9521
Author(s):  
Ryotaro Miyake ◽  
Hiroyuki Sasahara ◽  
Atsushi Suzuki ◽  
Seigo Ouchi
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Additive Manufacturing ◽  
Cutting Force ◽  
Deposition Process ◽  
Plasma Welding ◽  
Finishing Process ◽  
Subtractive Manufacturing ◽  
Profile Machining ◽  
Wall Profile

We investigated the fabrication and finishing of wall-profile machining by wire and arc additive manufacturing (WAAM) employing plasma welding with Ti-6Al-4V wire. We fabricated and integrated a local shield and a cover for the area below the local shield to achieve higher shielding ability. The tensile strength of the fabricated object met the forging standard for Ti-6Al-4V, but elongation was about 7%. We also focused on the possibility of reducing the cutting force and increasing the efficiency of the finishing process by cutting workpieces softened by high temperature immediately after the deposition process. We investigated the cutting force and tool wear of the fabricated objects heated to 300 °C using ceramics tools. Results showed that although the cutting force was reduced at high temperature, the wear rate of the tools was high, and the increase in cutting force due to wear was significant.

scholarly journals Mesophase Pitch-Based Carbon Fibers: Accelerated Stabilization of Pitch Fibers under Effective Plasma Irradiation-Assisted Modification

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6382
Author(s):  
Yuanshuo Peng ◽  
Ruixuan Tan ◽  
Yue Liu ◽  
Jianxiao Yang ◽  
Yanfeng Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Heating Rate ◽  
Carbon Fibers ◽  
High Performance ◽  
Low Cost ◽  
Tensile Modulus ◽  
Mesophase Pitch ◽  
Stabilization Time ◽  
Plasma Irradiation

Stabilization is the most complicated and time-consuming step in the manufacture of carbon fibers (CFs), which is important to prepare CFs with high performance. Accelerated stabilization was successfully demonstrated under effective plasma irradiation-assisted modification (PIM) of mesophase pitch fibers (PFs). The results showed that the PIM treatment could obviously introduce more oxygen-containing groups into PFs, which was remarkably efficient in shortening the stabilization time of PFs with a faster stabilization heating rate, as well as in preparing the corresponding CFs with higher performance. The obtained graphitized fiber (GF-5) from the PF-5 under PIM treatment of 5 min presented a higher tensile strength of 2.21 GPa, a higher tensile modulus of 502 GPa, and a higher thermal conductivity of 920 W/m·K compared to other GFs. Therefore, the accelerated stabilization of PFs by PIM treatment is an efficient strategy for developing low-cost pitch-based CFs with high performance.

Validation of a low-cost selective powder deposition process through the characterization of tin bronze specimens

2021 ◽  
pp. 146442072110319
Author(s):  
Samuel Magalhães ◽  
Manuel Sardinha ◽  
Carlos Vicente ◽  
Marco Leite ◽  
Relógio Ribeiro ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Low Cost ◽  
Deposition Process ◽  
Metal Powders ◽  
Tin Bronze ◽  
Powder Deposition ◽  
Manufacturing Technologies ◽  
The Cost

Additive manufacturing technologies are becoming increasingly popular due to their advantages over traditional subtracting manufacturing technologies. Despite advances in this field, fixed and maintenance costs for additive manufacturing with metals remain high. The introduction of low-cost metal machines in the additive manufacturing market considerably reduces the cost of acquiring and maintaining this type of equipment. This work aims to establish the process requirements for a low-cost selective powder deposition process, and validate it through the production of specimens in the laboratory and evaluate their mechanical properties. Tin bronze specimens were produced under different manufacturing conditions, namely powder dimensions, type of crucible and coke, firing segments and casting strategy. The morphology and chemical composition of the specimens were carried out combining the scanning electron microscopy and energy dispersive X-Ray spectroscopy techniques, respectively. It was observed that crucibles and coke with impurities that react with the metal powders and infill in a reducing atmosphere have influence in the final quality of parts. Tested samples displayed high variability of results which can be correlated with different manufacturing conditions. The selection of the appropriate print parameters led to the manufacture of tin bronze specimens with mechanical properties comparable to those reported in the literature. Overall, low-cost selective powder deposition is a promising technology, if identified manufacturing issues are addressed.

Effects of drawing process on the structure and tensile properties of textile-grade PAN fiber and its carbon fiber

e-Polymers ◽  
2014 ◽  
Vol 14 (3) ◽  
pp. 217-224 ◽  
Author(s):  
Hwayoung Lee ◽  
Lo-Woon Lee ◽  
Seung-Wook Lee ◽  
Han-Ik Joh ◽  
Seong-Mu Jo ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Carbon Fibers ◽  
Low Cost ◽  
Hot Water ◽  
Water Bath ◽  
Drawing Process ◽  
Tubular Furnace ◽  
Pan Fiber ◽  
Convection Oven

AbstractCarbon fibers (CFs) were prepared using low-cost, textile-grade polyacrylonitrile fibers, which were 200% to 400% drawn in a hot water bath at 90°C or/and in a tubular furnace at 180°C. X-ray diffractograms confirmed that the drawing process led to higher crystallinity and molecular orientation. These fibers were stabilized in a convection oven at 25–255°C for 390 min. After stabilization, carbonization was performed to obtain carbon fibers. The tensile strength of CFs without drawing was ∼0.8 GPa; however, CFs with 200% and 200% drawing in a hot water bath at 90°C and in a tubular furnace at 180°C, respectively, showed a tensile strength of ∼1.7 GPa. These results suggest that the drawing process of precursor fibers affected the tensile properties of the resulting CFs significantly.

Analysis of novel induction heating extruder for additive manufacturing using aluminum filament

2021 ◽  
pp. 095440542110144
Author(s):  
Gourav K Sharma ◽  
Piyush Pant ◽  
Prashant K Jain ◽  
Pavan K Kankar ◽  
Puneet Tandon
Keyword(s):  
Energy Source ◽  
Additive Manufacturing ◽  
Induction Heating ◽  
Infrared Imaging ◽  
Low Cost ◽  
A Priori ◽  
Deposition Process ◽  
Temperature History ◽  
Additive Manufacture ◽  
Semi Solid

Induction Heating (IH) method is gaining traction in the field of Additive Manufacturing (AM) as it is a low cost, clean, safe, and precise energy source. Wire as a feedstock material is highly efficient as compared to the powder form in terms of material utilization and economic viability. Thus, the combination of IH and wire feedstock delivery to additive manufacture a part has been explored on an in-house developed novel AM setup. The processing of aluminum wire (Al-5356) in semi-solid form from the extruder, heated using IH method has been performed. The approach adopted in this paper is to perform an in situ infrared imaging to analyze the evolution of thermal field during the extruder heating and metal deposition process. An effective thermal cartography has been undertaken to acquire temperature history of filament, extruder, and deposition process. The temperature profile plot is utilized to understand the temperature distribution and average temperature in the heating, extrusion, and layering process during layer fabrication. The presented work facilitates a priori anticipation to utilize IH as a potential energy source for the metal AM systems.

scholarly journals Natural Fibres as Reinforcement Strategy on Cork-Polymer Composites

2012 ◽  
Vol 730-732 ◽  
pp. 373-378 ◽  
Author(s):  
Emanuel M. Fernandes ◽  
Vitor M. Correlo ◽  
João F. Mano ◽  
Rui L. Reis
Keyword(s):  
Tensile Strength ◽  
Coupling Agent ◽  
Mechanical Performance ◽  
Low Cost ◽  
Tensile Modulus ◽  
Acoustic Properties ◽  
Added Value ◽  
Homogeneous Distribution ◽  
New Class ◽  
Thermoplastic Matrix

Cork powder, the most important sub-product of cork processing, combined with thermoplastic matrixes like, high density polyethylene (HDPE), offer a new class of cork-polymer composite (CPC) materials with high added-value. Therefore, reinforcing strategies must be considered to increase the mechanical performance, especially when high content of cork powder is added to the formulation. Coconut fibres have several advantages, such as, low density, renewable source, low cost and biodegradability. The use of these fibres on the reinforcement of CPC materials will not only contribute to improve the mechanical performance but also for increasing the amount of natural component present on the final composition. The main goal of this work was to prepare HDPE/cork (50-50 wt.%) composites reinforced with discontinuous coconut fibres (5 and 10 wt.%) with and without the addition of coupling agent (2 wt.%) by extrusion. The developed reinforced cork based composites were characterized regarding its morphology and mechanical performance. Optical micrographs have shown a homogeneous distribution of the fibres. The coupling agent effect on CPC performance was also investigated. The tensile strength and tensile modulus of the reinforced composites were significantly improved with the addition of coupling agent. The use of 10 wt.% of coconut fibres in the presence of coupling agent promote an increase on maximum tensile strength of around 41 % comparing with the HDPE/cork (50-50 wt.%) composites. Scanning electron microscopy (SEM) micrographs of the tensile fractured specimens confirmed that the use of coupling agent promoted the interfacial adhesion between the fibres and the thermoplastic matrix. Since, like cork powder, coconut fibres have good thermal and acoustic properties, we consider that the novel reinforced CPC herein described have high potential to be used in building and construction systems and other structural 3D applications.

scholarly journals Study of the Mechanism of a Stable Deposited Height During GMAW-Based Additive Manufacturing

2020 ◽  
Vol 10 (12) ◽  
pp. 4322
Author(s):  
Hongyao Shen ◽  
Rongxin Deng ◽  
Bing Liu ◽  
Sheng Tang ◽  
Shun Li
Keyword(s):  
Additive Manufacturing ◽  
Low Cost ◽  
Gas Metal Arc Welding ◽  
Research Work ◽  
Dimensional Accuracy ◽  
Deposition Process ◽  
High Deposition Rate ◽  
Thin Wall ◽  
Forming Process ◽  
Layer Height

Gas metal arc welding (GMAW)-based additive manufacturing has the advantages of a high deposition rate, low cost, the production of a compact and dense microstructure in the cladding layer, and good mechanical properties, but the forming process is unstable. The shape of the welding bead critically affects the layer height and dimensional accuracy of the parts manufactured, and it is difficult to control. A series of experiments were designed and the results indicated that when the value of the predefined layer height is set in a certain range and other parameters are held constant, the height of the thin wall produced by GMAW-based additive manufacturing is almost equal to the predefined layer height multiplied by the number of layers. This research work shows that during the GMAW process, the changes in the distance between the torch and the top surface of the part cause a variety of dry extensions of the electrode; furthermore, the changes lead to a variety in the heat input into the molten pool. Therefore, the dry extension of the electrode is the key factor influencing the geometry of the welding bead, especially the layer height, and it has a compensating effect that makes the actual layer height close to the predefined value. A three-dimensional numerical model was established to study the influence of the predefined layer height to the fluid flow and heat transfer behaviors during the weld-deposition process.

scholarly journals Rheological Issues in Carbon-Based Inks for Additive Manufacturing

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 99 ◽  
Author(s):  
Charlie O’Mahony ◽  
Ehtsham Ul Haq ◽  
Christophe Sillien ◽  
Syed A.M. Tofail
Keyword(s):  
Additive Manufacturing ◽  
Carbon Fibers ◽  
Carbon Materials ◽  
Low Cost ◽  
Complex Geometries ◽  
Flow Properties ◽  
Manufacturing Method ◽  
Commercial Market ◽  
Conductive Properties ◽  
Carbon Based

As the industry and commercial market move towards the optimization of printing and additive manufacturing, it becomes important to understand how to obtain the most from the materials while maintaining the ability to print complex geometries effectively. Combining such a manufacturing method with advanced carbon materials, such as Graphene, Carbon Nanotubes, and Carbon fibers, with their mechanical and conductive properties, delivers a cutting-edge combination of low-cost conductive products. Through the process of printing the effectiveness of these properties decreases. Thorough optimization is required to determine the idealized ink functional and flow properties to ensure maximum printability and functionalities offered by carbon nanoforms. The optimization of these properties then is limited by the printability. By determining the physical properties of printability and flow properties of the inks, calculated compromises can be made for the ink design. In this review we have discussed the connection between the rheology of carbon-based inks and the methodologies for maintaining the maximum pristine carbon material properties.

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