•Effect of printing speed is studied on tensile and fracture properties of ABS specimens made by FDM.•Path of crack growth is also analyzed for specimens made by different printing speeds.•Within the ...studied printing speeds, the sample produced with 70 mm/s printing speed shows the best fracture resistance.•This can be attributed to stronger interlayer bonding in these additively manufactured specimens.
The current paper deals with the influence of printing speed on the tensile and fracture strength of Acrylonitrile Butadiene Styrene (ABS) specimens made by Fused Deposition Modeling (FDM) technique. Four different printing speeds of 10, 30, 50, and 70 mm/s are used to fabricate dog-bone and Semi-Circular Bending (SCB) specimens for examining the mechanical and fracture performance of FDM-ABS parts, respectively. Due to the plastic deformation in the crack tip zone of SCB specimens prior to fracture initiation, the critical value of J-integral is chosen as the fracture characterizing parameter. Therefore, elastic–plastic finite element analyses are performed to calculate the critical values of J-integral (Jc). According to the experimental results, the fabricated specimens with a printing speed of 70 mm/s shows the best performance with the maximum elongation and fracture resistance compared to the other printed specimens with different nozzle speeds. For exploring the failure mechanisms in the tensile specimens Scanning Electron Microscopy (SEM) is utilized and various failure mechanisms have been presented and discussed. These observations are then linked to the tensile and fracture properties of the studied specimens.
Fused-deposition modeling (FDM), one of the additive manufacturing (AM) technologies, is an advanced digital manufacturing technique that produces parts by heating, extruding and depositing filaments ...of thermoplastic polymers. The properties of FDM-produced parts apparently depend on the processing parameters. These processing parameters have conflicting advantages that need to be investigated. This article focuses on an investigation into the effect of these parameters on the flexural properties of FDM-produced parts. The investigation is carried out on high-performance ULTEM 9085 material, as this material is relatively new and has potential application in the aerospace, military and automotive industries. Five parameters: air gap, raster width, raster angle, contour number, and contour width, with a full factorial design of the experiment, are considered for the investigation. From the investigation, it is revealed that raster angle and raster width have the greatest effect on the flexural properties of the material. The optimal levels of the process parameters achieved are: air gap of 0.000 mm, raster width of 0.7814 mm, raster angle of 0°, contour number of 5, and contour width of 0.7814 mm, leading to a flexural strength of 127 MPa, a flexural modulus of 2400 MPa, and 0.081 flexural strain.
Since the inception of 3D concrete printing (3DCP) in the early to mid-2000's, the commercial landscape for this technology has expanded rapidly in parallel with developments of relevant materials, ...production technologies and knowhow. To benchmark the state-of-the-art of 3DCP technology in the construction field, this study presents a systematic review and analysis of 3DCP's development and applications based on information from articles, patents and publicly available data. An estimation of Technology Readiness Level (TRL) for 3DCP has been formulated through expert review, and the evidence suggests this is in the region of TRL6-7 similar to that reported for polymer-based fused deposition modelling processes. A new schema for the TRL assessment process is suggested and applied to two case studies: 1) the production of decorative works; 2) the fabrication of dwellings. Finally, we have identified four frontiers for research and development that should be exploited to raise the TRL of 3DCP.
Fused deposition modelling is one of the additive manufacturing processes in which a semi-solid polymer material is deposited line-by-line to construct 3D objects direct from computer aided design ...(CAD) models. Benefits inherent with additively manufacturing allowed effective competition with other traditional methods in specific applications and the process drew sufficient research attention. The nature of material deposition and the mechanics of solid state sintering lead to varying levels of inter-road and inter-layer bonding resulting in a composite structure of voids interspersed in the base material matrix. While there are other parameters also, the raster angle in particular has a direct bearing on the resulting meso-structure and together with the rate of inter-road coalescence plays a significant role in influencing the mechanical characteristics of parts produced. Experimental and analytical attempts were made in the past to evaluate the role of raster angle orientation, but the resulting material properties were taken to be those of the base material. The hypothesis for the current research is that the mechanical properties resulting from fused deposition modelling are structure-sensitive. Experimental and analytical models are developed to test this hypothesis and the results indicate the hypothesis to be true.
Additive Manufacturing (AM) is a game changing production technology for aerospace applications. Fused deposition modeling is one of the most widely used AM technologies and recently has gained much ...attention in the advancement of many products. This paper introduces an extensive review of fused deposition modeling and its application in the development of high performance unmanned aerial vehicles. The process methodology, materials, post processing, and properties of its products are discussed in details. Successful examples of using this technology for making functional, lightweight, and high endurance unmanned aerial vehicles are also highlighted. In addition, major opportunities, limitations, and outlook of fused deposition modeling are also explored. The paper shows that the emerge of fused deposition modeling as a robust technique for unmanned aerial vehicles represents a good opportunity to produce compact, strong, lightweight structures, and functional parts with embedded electronic.
Fused deposition modeling (FDM) and Unmanned Ariel vehicles (UAVs), are fast growing technologies, have attracted a great deal of attention. This review studies the process methodology challenges, opportunities, and outlook of FDM and its application in the development of high performance UAVs.
3D-printable, flexible, and conductive thermoplastic-based material was successfully developed for strain sensing applications. Thermoplastic polyurethane/multiwalled carbon nanotube (TPU/MWCNT) were ...compounded, their filaments were extruded, and the sensors 3D printed using fused deposition modeling. Mechanical, electrical, and piezoresistivity behaviors were investigated under monotonous and cyclic loadings. MWNCTs enhanced the printing capability of TPU by increasing its stiffness. Very modest decreases were observed in the elasticity modulus of printed nanocomposites (~14%, compared to that of bulk counterparts), indicating excellent interlayer adhesion and superior performance to those reported in literature. Consequently, the conductivity was largely preserved after printing, in both through-layer and cross-layer directions. The piezoresistivity gauge factors of as high as 176 were achieved under applied strains as large as 100%. A highly repeatable resistance-strain response was also obtained under cyclic loadings. The results demonstrate TPU/MWCNT as an excellent piezoresistive feedstock for 3D printing with potential applications in wearable electronics, soft robotics, and prosthetics, where complex design, multi-directionality, and customizability are demanded.
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•Flexible TPU/MWCNT was successfully 3D-printed as a sensing sensor.•The presence of MWCNT enhanced the printability of TPU.•Mechanical and electrical properties were highly preserved after 3D printing.•Printed sensors showed excellent cyclic piezoresistivity behavior.•Gauge factors as high as 176 were achieved.
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Microneedles as novel transdermal drug delivery systems have lately attracted extensive attention due to their distinguished properties, including improved patient compliance and ...self-administration, compared to traditional parenteral administrations such as intravenous injection, intramuscular injection and subcutaneous injection. However, the great difficulties of precisely manufacturing those microneedles and patches within micro scale have strongly retarded their commercialization and clinical applications, particularly for the personalized medicine. Recently, numerous researches of utilizing 3D-priting process to fabricate transdermal drug delivery systems have been reported, not only adopting versatile printing methodologies, but also utilizing with different formulation strategies, to fabricate both artificial cargo delivery systems and sophisticated bio-inspired microneedles. This review aims to summarize those lately reported studies and to elaborate their advantages and limitations, discussing promising potential applications as novel drug delivery systems.
In recent years, there have been significant advances on materials development for additive manufacturing (AM) applications. However, the use of composites or nanocomposite materials for improved ...performance and multifunctionality are still limited. This review paper attempts to provide a comprehensive review of both commercially available materials as well as research activities related to recent progress on high-performance polymer nanocomposites that are being used in various AM techniques. Four AM techniques including Fused Filament Fabrication (FFF), Selective Laser Sintering (SLS), Multi Jet Fusion (MJF), and Stereolithography (SLA) are discussed. The development of printable polymer composites especially polymer nanocomposites is rapidly expanding the AM materials portfolio, which makes the production of multifunctional parts with complex structures possible.
We investigate the influence of raster layup on the resulting material properties of FDM 3D-printed materials made of PLA. In particular, we investigate the resulting toughness, strength, and ...stiffness, with a special focus on toughness. We show that for standard layups with layer orientations alternating by 90°, stiffness and strength are almost isotropic, while a strong anisotropy is obtained for toughness. Moreover, we show that materials with such a layup can even switch their behavior from brittle to ductile depending on the loading direction. Finally, we propose a new layer stacking scheme which simultaneously provides increased toughness and increased strength compared to the standard approaches.
The objective of this study was to compare the physical and mechanical performance of poly(lactic acid) (PLA), acrylonitrile butadiene styrene (ABS), and nylon 6 fabricated using fused deposition ...modeling (FDM) and conventional injection molding. It is found that different processing methods did not affect the viscosity of the samples, and the percentage difference for the density measurement is less than 4%. Water absorption of FDM samples is approximately 108% higher compared to those fabricated using the injection molding. The results also revealed that the FDM method did not strongly affect the degree of crystallinity of ABS, but it increased the degree of crystallinity of PLA and nylon 6. The tensile strength, Young's modulus, elongation at break, and impact strength of FDM samples were approximately 48%, 50%, 48%, and 78%, lower compared with the injection molded samples. The results presented can provide a guide to manufacturing the final products using FDM with the desired performance.
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