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Distortion in overhangs depending on the overhang angle. (a) Visual representation of EBM overhang distortion. (b) EBM and LPBF distortion plotted against overhang angle.
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Metal powder bed-based Additive Manufacturing (AM) technologies, such as Electron Beam-Melting (EBM) and Laser Powder Bed Fusion (LPBF), are established in several industries due to the large design freedom and mechanical properties. While EBM and LPBF have similar operating steps, process-specific characteristics influence the component design. Th...
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Context 1
... though absorption was considered in the calculation of the volume energy density, the preheating strategy during EBM significantly affected the melt-pool size. Figure 7a shows the distortion of EBM overhangs. It can be seen that the distortion increases with an increasing overhang angle, reaching a maximum at a 90° overhang. ...
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... can be seen that the distortion increases with an increasing overhang angle, reaching a maximum at a 90° overhang. GOM scans of LPBF samples are similar to EBM results up to 55° overhang, as shown in Figure 7b; however, samples with an overhang angle larger than 65° had to be discontin- In the case of LPBF cubes, the melt-pool depth d was approximately 160 µm. Its width t was approximately 140 µm. ...
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... though absorption was considered in the calculation of the volume energy density, the preheating strategy during EBM significantly affected the melt-pool size. Figure 7a shows the distortion of EBM overhangs. It can be seen that the distortion increases with an increasing overhang angle, reaching a maximum at a 90 • overhang. ...
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... can be seen that the distortion increases with an increasing overhang angle, reaching a maximum at a 90 • overhang. GOM scans of LPBF samples are similar to EBM results up to 55 • overhang, as shown in Figure 7b; however, samples with an overhang angle larger than 65 • had to be discontinued during the build due to warping. Based on the available literature on overhangs, the results are as expected [40][41][42][43]. ...
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Laser powder bed fusion (L-PBF) additive manufacturing technology is suitable for the direct 3D printing of geometrically complex periodic micro-rod-lattices. However, controlling the geometric and performance consistency remains challenging due to manufacturability limitations, non-negligible process defects, and surface roughness, which is inconv...
Citations
... These applications are due to the accuracy, precision, and efficiency of 3D printing (Zhu et al., 2021). Several types of 3D printing technologies are commercially available, i.e., fused deposition modelling (FDM) (Mwema et al., 2020), stereolithography (SLA) (Huang et al., 2020), digital light processing (DLP) (Kadry et al., 2019), selective laser sintering (SLS) (Tabriz et al., 2023), selective laser melting (SLM) (Neikov, 2019), electron beam melting (EBM) (Megahed et al., 2022), binder jetting (Mostafaei et al., 2021), and material jetting (Gülcan et al., 2021). FDM utilizes thermoplastic filament as the printing material, although there are other commonly used materials for FDM 3D printings. ...
Plastics are a wide range of synthetic or semi-synthetic materials, mainly consisting of polymers. The use of plastics has increased to over 300 million metric tonnes in recent years, and by 2050, it is expected to grow to 800 million. Presently, a mere 10% of plastic waste is recycled, with approximately 75% ended up in landfills. Inappropriate disposal of plastic waste into the environment poses a threat to human lives and marine species. Therefore, this review article highlights potential routes for converting plastic/microplastic waste into valuable resources to promote a greener and more sustainable environment. The literature review revealed that plastics/ microplastics (P/MP) could be recycled or upcycled into various products or materials via several innovative processes. For example, P/MP are recycled and utilized as anodes in lithium-ion (Li-ion) and sodium-ion (Na-ion) batteries. The anode in Na-ion batteries comprising PP carbon powder exhibits a high reversible capacity of ~340 mAh/g at 0.01 A/g current state. In contrast, integrating Fe 3 O 4 and PE into a Li-ion battery yielded an excellent capacity of 1123 mAh/g at 0.5 A/g current state. Additionally, recycled Nylon displayed high physical and mechanical properties necessary for excellent application as 3D printing material. Induction heating is considered a revolutionary pyrolysis technique with improved yield, efficiency, and lower energy utilization. Overall, P/MPs are highlighted as abundant resources for the sustainable production of valuable products and materials such as batteries, nanomaterials, graphene, and membranes for future applications.
... Depending on the source of publication, the majority of the publications, resulting in 38 publications (70,4%) were articles, whereas the remaining 16 publications (29,6%) were conference proceedings, as presented in Table 1. [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48] 38 70,4 ...
... Material Extrusion [11], [13], [19], [23], [25], [26], [27], [38], [39], [41], [43], [45], [46], [51], [52], [53], [61], [62] 18 33,30 Powder Bed Fusion [12], [16], [17], [18], [20], [21], [24], [28], [29], [30], [32], [33], [34], [35], [42], [46], [48], [49], [54], [63], [ ...
Additive Manufacturing (AM) has made a giant leap across numerous fields and industries, enabling the manufacturing of complex components in layer-by-layer form customized to the needs of the customer. This paper aims to outline current trends, review present issues and opportunities, and classify different AM techniques and their fields of application. With the objective of providing a thorough understanding of the seven AM techniques defined by The American Society for Testing and Materials (ASTM), this literature analysis identifies research gaps for future applications and highlights noteworthy findings.
... Additionally, the high process temperatures maintained during EPBF cause sintering of surrounding powder onto the part surface and increase the surface roughness of the part sides or walls. Extensive powder sintering is not generally a concern for LPBF, where lower preheating temperatures are used (e.g., 200 °C in Ref. [19]). For these reasons, parts printed with LPBF generally exhibit lower surface roughness than EPBF-printed parts [19,20]. ...
... Extensive powder sintering is not generally a concern for LPBF, where lower preheating temperatures are used (e.g., 200 °C in Ref. [19]). For these reasons, parts printed with LPBF generally exhibit lower surface roughness than EPBF-printed parts [19,20]. Therefore, determining the feasibility of printing with smaller mean particle size PSDs in EPBF could potentially lead to corresponding surface improvements in EPBF. ...
An electron beam powder bed fusion (EPBF) printability study of a medium-C hot-work tool steel with focus on part density and surface roughness was performed using three different powder particle size distributions (PSDs) of 45–105 \(\mathrm{\mu mmm}\) (typical for EPBF), 20–60 \(\mathrm{\mu mmm}\) (typical for laser beam powder bed fusion), and a 50–50 wt.% mixture of these two powders. First, acceptable process parameter windows were generated based on as-printed density for each PSD. Full density parts (at least 99.5% dense according to NIST) were produced using the 20–60 \(\mathrm{\mu mmm}\) PSD and the mix PSD. Fifteen different contouring strategies were also tested for potential improvement of the as-printed side surface roughnesses, which ranged from 23.3 to 25.7 \(\mathrm{\mu mmm}\) among the three PSDs. Side surface roughness as low as 13.8 \(\mathrm{\mu mmm}\) was attained by using contouring strategies employing two contouring lines, which were typically observed to be more effective than one-line strategies. Overall, the 20–60 \(\mathrm{\mu mmm}\) PSD was determined to convey a better as-printed build quality over a wider range of parameters without sacrificing process productivity.
... The appearance of microstructural gradient from 10 and 10þ layers (thickness!500 mm) deposition can be explained by process intrinsic annealing and melt pool formation. The melt pool depth due to beam penetration in EB-PBF is reported in the range of 200e250 mm [32], which is equivalent to 4e5 layers. The melt pool radiates significant heat very quickly to the environment due to immediate contact resulting in a faster cooling rate near the top in Region I [29]. ...
... Diferentes autores han descrito que la modificación de los parámetros de manufactura afecta la calidad geométrica y superficial de la pieza que se está manufacturando, al igual que algunas propiedades mecánicas de la pieza [13], [23], [24], [25]. ...
... The heat input, combined with the elevated preheat temperature throughout the build (i.e., 350 °C), leads to grain coarsening. The effect of in situ heat treatment during EBM has previously been reported [16,27]. The grain size of the 7.7 J/mm 2 sample does not follow the increasing grain size with energy density trend. ...
Due to the increasing demand for electrification in the automotive sector, the interest in the manufacturing and processing of pure Copper (Cu; purity 99.99%) is also increasing. Laser-based technologies have proven to be challenging due to Cu’s high optical reflectivity. Processing pure Cu with Electron Beam Melting (EBM) is a promising manufacturing route, allowing for high design freedom. The highest priority is to achieve outstanding thermal and electric conductivity in manufactured Cu components. Chemical contamination or manufacturing defects, such as porosity, significantly reduce the thermal and electric conductivity. The literature on post-processing (thermal and abrasive) of additively manufactured Cu is scarce. Therefore, this study discusses the correlation between as built and heat treated microstructure, as well as surface roughness on the EBM electric conductivity. EBSD analysis is performed to analyze the effect of microstructure on electric conductivity. The effect of sandblasting and vibratory finishing on surface roughness and electric conductivity is investigated. Additionally, the samples are mechanically tested in terms of hardness.
... The additive repair experiences much higher cooling rates (i.e., 10 6 K/s [29,37]) compared to the conventional preform. The fast cooling rate leads to grain refinement within the additive repair causing higher strength according to the Hall-Petch relation [38,39]. Similar results were found by Tian et al. with regards to tensile properties [40]. ...
High pressure die casting (HPDC) tools undergo several repairs during their life cycle. Traditional repair methods (e.g., welding) cannot always be applied on damaged tools, necessitating complete replacement. Usually, direct energy deposition (DED) is considered and applied to repair tools. In this study, the potential of laser powder bed fusion (LPBF) for HPDC tool repair is investigated. LPBF of the hot work tool steel 1.2343/H11 normally requires preheating temperatures above 200 °C to overcome cracking. Therefore, a process window for the crack-susceptible hot work tool steel 1.2343/H11 with no preheating was developed to avoid preheating an entire preform. Laser power, hatch distance, and scan speed are varied to maximize relative density. Since the correlation of LPBF process parameters and resulting build quality is not fully understood yet, the relationship between process parameters and surface roughness is statistically determined. The identification of suitable process parameters with no preheating allowed crack-free processing of 1.2343/H11 tool steel via LPBF in this study. The LPBF repair of a volume of ~2000 cm3 was successfully carried out and microstructurally and mechanically characterized. A special focus lays on the interface between the worn HPDC tool and additive reconstruction, since it must withstand the mechanical and thermal loads during the HPDC process.
Developing patient-specific implants has an increasing interest in the application of emerging additive manufacturing (AM) technologies. On the other hand, despite advances in total knee replacement (TKR), studies suggest that up to 20% of patients with elective TKR are dissatisfied with the outcome. By creating 3D objects from digital models, AM enables the production of patient-specific implants with complex geometries, such as those required for knee replacements. Previous studies have highlighted concerns regarding the risk of residual stresses and shape distortions in AM parts, which could lead to structural failure or other complications. This article presents a computational framework that uses CT images to create patient-specific finite element models for optimizing AM knee replacements. The workflow includes image processing in the open-source software 3DSlicer and MeshLab and AM process simulations in the commercial platform 3DEXPERIENCE. The approach is demonstrated on a distal femur replacement for a 50-year-old male patient from the open-access Natural Knee Data. The results show that build orientations have a significant impact on both shape distortions and residual stresses. Support structures have a marginal effect on residual stresses but strongly influence shape distortions, whereas conical support exhibits a maximum distortion of 18.5 mm. Future research can explore how these factors affect the functionality of AM knee replacements under in-service loading.
