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3D printing, specifically fused deposition modeling (FDM) of poly-ether-ether-ketone (PEEK), is one of the most powerful and efficient state-of-the-art manufacturing techniques. However, FDM of PEEK is challenging. Indeed, it is critical to consider specific 3D printing parameters and filament feedstock quality to achieve optimum mechanical properties in the 3D-printed PEEK parts. In this paper, we investigate the effect of specific 3D printing parameters such as nozzle and chamber temperature, print speed, and layer height on the mechanical properties of 3D-printed PEEK. Moreover, we explore the effect of filament quality on the structures' mechanical properties. In that regard, we developed PEEK filaments using a customized extruder setup in-house and used those laboratory-developed filaments (LD) to 3D print PEEK structures suitable for mechanical testing (tensile, compression, and flexural testing) and compared them to the mechanical properties of 3D-printed parts that were developed using commercially available (CA) filaments. Results indicate that an optimum combination of a nozzle and chamber temperature, print speed, and layer height is appropriate to achieve 3D-printed parts with optimum mechanical properties. Notably, results confirmed no significant differences between the specimen groups developed using LD and CA filaments, highlighting that the LD filaments were of comparable quality to the CA ones. The highest mean strengths recorded for the parts printed with the LD filaments were 106.45 MPa (compressive), 85.43 MPa (tensile), and 102.63 MPa (flexural). This paper confirms that high-quality PEEK-based filaments can be developed in-house to yield 3D-printed PEEK parts with optimum mechanical properties. [ABSTRACT FROM AUTHOR]

The spread of 3D printing in many different fields has become eminent. This paper aims to improve the mechanical properties of parts printed by fused deposition modeling technique. Acrylonitrile butadiene styrene (ABS) specimens are printed with custom printing parameters. These parameters give a tensile strength that is 86% of the injection- molded ABS strength, and give one of the best recorded results for 100% infill printed ABS tensile specimens. Furthermore, a post filling technique has been studied. Specimens are printed with inner voids and different densities using slicing software. Void shape is precisely selected to conform to the filling process. High-strength, low-cost thermoset resin is injected through specimens to fill those voids. A tensile test has been performed after the full curing of the resin. A morphology analysis is done. Using this technique strength to printed weight ratio is improved by 151% and the cost is reduced by 51%. [ABSTRACT FROM AUTHOR]

In recent years, 3D printing technology has played an essential role in fabricating customized products at a low cost and faster in numerous industrial sectors. Fused deposition modeling (FDM) is one of the most efficient and economical 3D printing techniques. Various materials have been developed and studied, and their properties, such as mechanical, thermal, and electrical, have been reported. Numerous attempts to improve FDM products' properties for applications in various sectors have also been reported. Still, their applications are limited due to the materials' availability and properties compared to traditional fabrication methods. In 3D printing, the process parameters are crucial factors for improving the product's properties and reducing the machining time and cost. Researchers have recently investigated many approaches for expanding the range of materials and optimizing the FDM process parameters to extend the FDM process's possibility into various industrial sectors. This paper reviews and explains various techniques used in 3D printing and the various polymers and polymer composites used in the FDM process. The list of mechanical investigations carried out for different materials, process parameters, properties, and the FDM process's potential application was discussed. This review is expected to indicate the materials and their optimized parameters to achieve enhanced properties and applications. Also, the article is highly anticipated to provide the research gaps to sustenance future research in the area of FDM technologies. [ABSTRACT FROM AUTHOR]

Laser powder deposition (LPD), as one of the most widely used additive manufacturing methods for metals, is an important rapid prototype manufacturing and repairing method for large components. However, great challenges exist in LPD of aluminum alloy due to the high reflectivity to laser, the poor fluidity of the powder, the high porosity in the printed component, and the crack sensitivity, which blocks the performance of the printed structure and limits its application. Recently, various researchers have focused on LPD of aluminum alloys and explored its potential mechanism. This paper reports on the recent advances in this area and highlights the key topics requiring attention, presenting the knowledge gaps in this industry. Our work aims to develop a comprehensive understanding of the interrelation among the various aspects of the subject suggesting directions for improvement in producing aluminum alloy structure with LPD. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) technology is capable of efficiently building complex shapes when compared with traditional manufacturing methods. Fused deposition modeling (FDM) is one of the AM processes, and it produces a great variety of polymeric parts. Therefore, it is essential to determine the relationship that exists among its process parameters, productivity and sustainability, quality of the final piece, and its structural performance. This paper presents an experimental study centered on optimizing five responses associated with FDM: energy consumption of the 3D printer, processing time, part's dimensional accuracy, the quantity of material used to print the pieces, and mechanical strength of the specimens. The model material employed was acrylonitrile styrene acrylate. The effects of five key process parameters on the responses were studied using the Taguchi methodology and analysis of variance (ANOVA). These parameters were layer thickness, filling pattern, orientation angle, printing plane, and position of the piece on the build platform. A desirability analysis was employed to determine the set of process parameters that provided the best trade-off among all the considered variables. The results showed that the approach presented in this work allowed for simultaneous optimization of all the observed variables for the 3D printing process. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) has various independent parameters that affect the mechanical properties and quality of the produced parts that are not linearly the function of each other. Process parameters in metal AM are very hard to control, analyse and optimise because they affect each other even though they can be independently changed. Changing process parameters in a wide range is not possible due to the formation of problems such as cracks, balling, unmelted powders, porosity and distortion. In this paper, a numerical model to predict the value of tensile strength of selective laser melting (SLM) Ti-6Al-4V parts and analyse the effect of process parameters on the results has been proposed. Taguchi L25 Design of Experiment (DOE) across 125 samples to create a comprehensive and general overview of influential parameters on the build process was investigated. Specifically, parameters included laser power, scan speed, hatch spacing, laser pattern angle and heat treatment (HT). To evaluate and analyse the build process according to established statistical variances, a minimum of five samples based on ASTM standard (for tensile test) were prepared. Heat treatment was added to the DOE to analyse the combined process and post-process effects. Results were compared (cross-validated) against existing values found in the literature and were found to effectively predict and explain the behaviour of tensile strength when changing process parameters. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the effect of printing parameters and their interactions on the mechanical properties of ABS-based specimen, 3D printed by fused deposition modeling (FDM), using the response surface method. The manufacturing direction (X, Y, or Z) and the deposition angle (0°, 30°, or 45°) are analyzed as input factors. The Young modulus, the yield stress, the tensile strength, and the deformation at fracture in tension are considered as responses. An empirical model for each response is built in terms of factors and their interactions. The predicted results are in good coherence with experimental ones. The original contribution of this paper consists in the evaluation of the optimal combination of manufacturing parameters thanks to the MINITAB software. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) started as a rapid prototyping (RP) technology to aid in visualizing and validating designs in the design process. However, with the recent improvements in metal AM parts, functional parts can be manufactured using laser-based AM. Currently, metal AM parts have comparable mechanical properties to traditional manufacturing parts. 15-5PH stainless steel and Inconel 718 are two of the most commonly used metals in laser-based AM, and they have a high modulus of elasticity and tensile strength and can be precipitate hardened to increase their strength and hardness by heat treatment. These properties make 15-5PH stainless steel and Inconel 718 suitable for many industrial applications such as aerospace and automotive. However, due to the nature of AM, AM parts usually suffer from anisotropy. In this paper, the mechanical properties such as tensile strength, modulus of elasticity, yield strength, and ductility are investigated at various elevated temperatures up to 350 °C and compared with the mechanical properties at room temperature using specimens printed in three different orientations to capture the effect on the anisotropy. In addition to that, the microstructure of the specimens is studied to investigate the influence of elevated temperature on the specimens. [ABSTRACT FROM AUTHOR]

In this paper, the effect of additive particles on the mechanical properties of ultraviolet (UV)-cured resin was evaluated based on tensile strength and shear strength. The experimental results showed that the tensile strength was improved with proper particle addition, but the shear strength was always decreased. Moreover, the effects of additive particles on the holding force of diamond abrasive, critical exposure energy, and penetration depth of UV-cured resin were elucidated. The holding force of resin with 15 wt.% Al2O3 addition was found to be higher than that of pure UV resin. Based on the experimentally determined critical UV exposure energy and penetration depth, UV-cured resins with and without additive particles were used to fabricate grinding wheels using additive manufacturing technology. Grinding experiment demonstrated the performance of UV resinoid grinding wheels was significantly improved with the addition of 15 wt.% Al2O3 particles. [ABSTRACT FROM AUTHOR]

In recent years, additive manufacturing (AM) has been developed for industrial applications due to its superior performance, such as in building complex parts, which are especially difficult to build when using traditional methods. However, the surface quality, and dimensional and geometric accuracies of AM parts do not exceed conventionally machined parts, which hinders the AM applications. To overcome these limitations, hybrid manufacturing (HM) technology, which combines AM and subtractive manufacturing (SM) technologies in a single workstation has received a great deal of attention in academic and industrial circles to enhance material utilization, part complexity and quality control when producing functional parts. In this paper, we present research achievements using ANSI 316L stainless steel parts via the HM process and analysis of its surface morphology and microstructural characteristics, densification behaviour and mechanical properties. Specimens before and after heat treatment were analysed and compared. The study also dealt with material characterization via the Archimedes method, scanning electron microscopy (SEM), X-ray polycrystalline diffractometer (XRD) and tensile measurements. This study provides a valuable guide to determining the effectiveness of the HM process and its use when producing engineering parts. [ABSTRACT FROM AUTHOR]

Electron beam melting (EBM) has been recognized as an emerging additive manufacturing technology, which allows the production of fully dense parts from various metals. The technique builds parts using an electron beam to melt metal powder, layer by layer, in a powder bed. Thus, complex parts, including internal structures, can be made directly from 3D CAD models without special fixtures and cutting tools. Much research is conducted to study the microstructure and mechanical properties of EBM-built parts or to investigate the effects of EBM process parameters on the quality of parts. However, using EBM for building new features on an existing part has received little attention from the research community. Due to its performance, EBM seems able to transform an end-of-life (EoL) part/existing part into a new part without returning to the level of raw material. The aim of this study is to validate such principle. In this paper, an EBM machine was used to produce new Ti-6Al-4V features on a Ti-6Al-4V plate, which was considered as a useful core retrieved from an EoL product. The built samples, including EBM-built features and Ti-6Al-4V plate, were investigated in terms of their microstructure and mechanical properties. The results showed that EBM technique allows new features with a suitable microstructure and controlled mechanical properties to be built on an existing part. Moreover, the EBM-built features have a strong bond with the existing part leading to the same mechanical characteristics as original part. These demonstrate that the EBM technology has a promising potential for producing new parts from EoL parts/existing parts. [ABSTRACT FROM AUTHOR]

Metal additive manufacturing is an emerging advanced technology, it differs from conventional manufacturing methods as machining, casting, and forging, which are either subtractive or forming. Firstly, the objective of this work is to elaborate a new 316L stainless steel material by selective laser melting (SLM) from metallic powder according to specific operating parameters, namely laser scanning speed and power. Secondly, the characterization of this developed material by 3D printing is carried out. For this purpose, metallographic observations and heat treatments at different temperatures 650, 800, and 1050 °C were performed. Thus, the contribution of this study is to develop procedure and tools to enhance their mechanical properties at the level of parts obtained by conventional processes. Therefore, samples were examined by X-RF, SEM, EDS mapping, density, and hardness measurements as well. The results show that mechanical properties of additive manufactured samples can be improved in certain conditions linked to operating parameters and heat treatment. Also, this work has allowed us to confirm the resistance of the 316L stainless steel developed by SLM to high temperatures. [ABSTRACT FROM AUTHOR]

This experimental study investigates the effects of process parameters for 3D printing polylactic acid (PLA) samples on both the mechanical properties obtained and the energy consumption in the fused deposition modelling (FDM) process. The explained experimental activities provide an in-depth evaluation of all the strategies adopted in different temperatures and scan speed strategies. The results, extracted in tensile strength, ultrasonic inspection (UT), and specific energy consumption (SEC), highlight the printing parameters that mainly affect the mechanical characteristics of the final workpieces and the energy consumption to find an appropriate energy-saving energy strategy for the PLA additive manufacturing process. The results indicate a more excellent uniformity of the molded material, reducing the printing time and total energy consumption at high speeds (V = 110 mm/s) and one level of temperature (T = 215 °C). A new efficiency index has been introduced to release guidelines to pursue the best setup compromise. [ABSTRACT FROM AUTHOR]

Fused depositional modeling (FDM) is one of the common methods for 3D printing of polymers, which is expanding in various industrial applications, scientific researches, and engineering applications due to its ability to make complex parts. In this research, molecular dynamics (MDs) simulation has been used to predict the physical and mechanical properties. Then, the mechanical properties of the printed parts were determined. The mechanical properties of 3D printed parts strongly depend on the correct selection of processing parameters. In this study, the effect of three important parameters such as infill density, printing speed, and layer thickness were investigated on the tensile properties of PLA specimens. For this purpose, standard specimens with four infill densities of 20%, 40%, 60%, and 80%, two speeds of 20 mm/s and 40 mm/s, and two thicknesses of 0.1 mm and 0.2 mm were printed and tested under quasi-static tensile test. In all printed specimens, the print angle is ± 45°. The obtained experimental outcomes from the tensile test revealed that with increasing the infilling density, the mechanical properties of the parts improve and increase significantly. However, at very high infilling densities, the samples behave more brittle, so in cases where the strength of the part is less important than its shape and appearance, a density of 40% is more suitable in terms of cost, material, and time savings. It was also noted that the printing speed has less effect on the mechanical properties of PLA parts. It was also observed that reducing the thickness of the layer, while slightly increasing the stiffness of the parts, makes the part extremely brittle, and on the other hand, it leads to increase in the dimensional accuracy and surface quality of the specimens. At infill density of 80%, the specimens had the highest stiffness and strength, but it exhibits a brittle behavior. Moreover, it can be deduced that by reducing the layer thickness although the modulus of elasticity increases a little, ductility is greatly affected. [ABSTRACT FROM AUTHOR]

Additive Manufacturing technology has a significant impact on the modern world because of its ability to fabricate highly complex computerized geometrics. Pure 3D-printed polymer parts have limited potential applications due to inherently inferior mechanical and anisotropic properties. For more utilization and versatility, the addition of fillers has enhanced their functionalities. 3D printing has innovative advantages including low cost, minimal wastage, customized geometry, and ease of material change. This review reveals the development of 3D printing techniques of matrix composite materials with improving properties and their applications in the fields of aerospace, automotive, biomedical, and electronics. A general introduction is given on AM techniques mainly fused deposition modeling (FDM), Powder-liquid 3D printing (PLP), selective laser sintering (SLS), stereolithography (SLA), digital light processing (DLP), and robocasting. Process methodologies and behavior of different filler additives, reinforcement fibers, nanoparticles, and ceramic polymer composites are discussed. Also, some major issues of difficulty including printing parameters, homogeneous desperation of fillers, nozzle clogging due to filler aggregation, void formation, augmented curing time, and anisotropic attributes are addressed. In the end, some capabilities and shortcomings are pointed out for further development of 3D-printing technology. [ABSTRACT FROM AUTHOR]

Fused deposition modelling is an additive manufacturing technology that is widely employed to produce good quality products with complex geometries at a low cost and with efficient manufacturing and delivery logistics. The mechanical properties can be enhanced by studying the numerous FDM parameters and by using new materials. In this work, was studied the mechanical properties tensile strength, flexural strength, and impact energy of 3D printed parts manufactured with FDM technology and PLA-graphene raw material by varying the infill and layer thickness parameters using a statistical technique CCD—central composite design. Due to the layered production process, 3D printed parts exhibit anisotropic behaviour. In the tests, the flat orientation and honeycomb infill pattern were maintained. The results showed that the mechanical properties improve as the linear layer thickness parameter increases. The behaviour was different in each test for the linear infill parameter. The mechanical properties, tensile strength and flexural strength, increased as the infill increased, while impact energy decreased as infill increased. The relationship between mechanical properties and printing time/weight was also evaluated. [ABSTRACT FROM AUTHOR]

A robotized laser/wire directed energy deposition (RLW-DED) process has been employed, specifically in applications where higher deposition rates or larger buildup envelopes are needed. However, this process might have limitations in printing certain complex shape parts. Fabricating parts with overhang sections, depending on the geometry, might cause a collision between the laser head and the buildup. Part segmentation and joining the elements back together has been presented to overcome those limitations. In this study, the welding of additively manufactured parts by RLW-DED has been proposed. Autogenous laser welding, performed at the same setup used for RLW-DED, was utilized to join the thin-walled 316LSi DED parts. Mechanical and microstructural testing were then performed on the welded samples. The results showed that the mechanical properties of welded DED parts are comparable with those of DED parts. Furthermore, a component of complex shape was fabricated to show the capability of the developed process. Therefore, the welding of RLW-DED parts can expand the application of 3D-printed parts in industry. [ABSTRACT FROM AUTHOR]

To predict the mechanical behavior of 3D printed products, it is important to understand the composite material properties and the effect that parameters of 3D printing process have on the properties of these materials. The mechanical properties of PLA-based composite materials were studied in this work. The mechanical properties of the hot pressed samples were compared to those of the 3D printed samples. The elongation at break and the yield strength of the samples fabricated by 3D printing are decreased by 15-60% compared to those for the hot pressed samples. It has been found that the mechanical properties of 3D printed samples do not practically depending on the deposition scheme. [ABSTRACT FROM AUTHOR]

Several 2219-Al components were produced by additive manufacturing with tungsten inert gas (TIG), and thin walls were selected to study the mechanical properties. Results show that the average hardness is 77.5 HV, and the deposited materials are not sensitive to post heat during manufacturing process. No significant difference of hardness can be defined between strips and inner layers. Tensile tests were performed on welding and building directions. The average ultimate strength is 237 MPa, which is only 57 % of the property of 2219-T6 (routinely used state). Analysis suggests that the insufficiency of tensile strength can be ascribed to the absence of precipitation strengthening effect during the manufacturing process. The material exhibits an isotropic feature in tensile properties. Fracture observation shows that θ phases are the initiations of cracks. The effect of decreasing loading areas, due to the strip-like distributing porosities, is insignificant in welding direction. However, in building direction, it influences the crack propagating path. [ABSTRACT FROM AUTHOR]