Search Results (2,755)

Additive manufacturing (AM) offers opportunities to advance the design and function of ceramic tooling in high temperature actinide pyrochemistry. In technical ceramics such as alumina, conventional forming techniques often restrict design flexibility and can limit experimental progress. In this study, we investigate the use of vat photopolymerization (VP) with commercial resins to fabricate large-scale alumina crucibles, reaching dimensions up to 125 mm, which is significantly larger than typically reported for dense VP ceramics. Notably, these additively manufactured components are produced using consumer-grade hardware, which limits process control, but offers significant upside in scalability and accessibility. Using microscopy and X-ray computed tomography, the VP alumina parts have high bulk densities above 95%, but also the prevalence of AM-induced artifacts and surface defects. Mechanical testing showed these defects to significantly reduce flexural strength and compromise part reliability. Electrorefining trials under sustained exposure to molten salts and metals reveal mixed results, with the AM material exhibiting high chemical compatibility, but mechanical failures due to the reduced strength were prevalent. Our findings illustrate both the promise and current limitations of AM ceramics for actinide chemistry, and point toward future improvements in process optimization, design strategies, and part screening to enhance performance and reliability. Full article

Laser wire additive manufacturing (LWAM) offers high deposition efficiency and excellent material utilization. However, manufacturing thin-walled structures with large inclination angles and no support remains a challenge. In this study, the influence of laser tilt angle on the formability of multi-layer inclined parts was systematically investigated. Results reveal that tilting the laser redistributes energy input along the inclination direction, stabilizing the melt pool and reducing angular deviation. Under a 20° tilt condition, thin-walled structures with inclination up to 70° were successfully fabricated, overcoming the limitation of conventional vertical deposition. Furthermore, a multi-inclination arch bridge structure was fabricated under optimized conditions, demonstrating good morphological appearance, dimensional accuracy (deviation within ±0.3 mm), and surface waviness (W < 0.12 mm). The findings provide new insights into the mechanism of energy redistribution in tilted LWAM and establish a promising strategy for manufacturing complex overhanging structures in aerospace and automotive industries. Full article

One of the limitations of additive manufacturing technology is the high surface roughness of finished products caused by the layered structure of the deposition and the effect of adhesion of unfused powder particles. This worsens the fatigue characteristics, wear resistance, and functional properties of the parts, which are especially important for critical applications in medicine, aviation, and mechanical engineering. The paper presents the results of a study on the possibility of using plasma electrolytic polishing for post-processing of products made of additively manufactured Ti6Al4V alloy to form a homogeneous surface with reduced roughness. The morphology, roughness, and tribotechnical characteristics of the surface after processing in a fluoride electrolyte were studied with varying voltage and polishing time. A 90% reduction in surface roughness is achieved by polishing at 300 V for 20 min. The results of tribological tests revealed that after the polishing of the oxidative wear mechanism is maintained, the temperature in the tribological contact zone decreases, and the load-bearing capacity of the surface increases (the Kragelsky–Kombalov criterion decreases). The greatest decrease in the friction coefficient by 2.1 times was observed with minimal surface roughness, when the largest average radius of rounding of the microprotrusions of the friction track microtopology is formed with a low value of the Kragelsky–Kombalov criterion. Full article

With the advent of the Industry 4.0 era, the manufacturing industry is implementing a range of novel technologies on the factory floor, leading to the generation of substantial quantities of production data. However, the development of analytics tools capable of processing these data and extracting valuable information for decision-making and production control lags behind. In addition, a noticeable amount of raw data collected from the factory floor is prone to errors, especially in small- and medium-sized manufacturing plants, and their processing often requires a laborious data cleaning process due to the limitations of the sensors and the noisy environment of the manufacturing facilities. This presents a challenge in utilizing factory floor production data effectively. This paper addresses the challenge by focusing on the parts flow data, which reflects the number of parts in each buffer as a function of time in a production system. In particular, we study the parts flow data in discrete-time serial production line models, assuming that the data are subject to random noise, and develop effective and robust algorithms that can effectively detect and correct errors in these data. To improve the computational efficiency for complex cases (longer lines, higher error rates, etc.), a decomposition-based approach is used to parallelize the computation procedure at implementation. Numerical experiments demonstrate that the proposed methods can enhance data quality by more than 40% and improve the accuracy of system performance metrics estimation by over 50% using corrected data. These improvements can facilitate more reliable process monitoring and production control in manufacturing environments. Full article

BJ3DP has unique advantages compared to other energy-beam-based additive manufacturing technologies, such as lower residual stress, arising from the lack of heat during the printing process and the uniformity of the sintering process. However, attaining both high density and dimensional precision in metallic materials remains a challenge in BJ3DP. This study presents a systematic investigation into the fabrication of high-melting-point pure chromium (Cr) via binder jetting 3D printing (BJ3DP), with a focus on optimizing the printing parameters and sintering conditions. An orthogonal experiment identified the optimal printing parameters as a layer thickness of 75 μm and a binder saturation of 60%, which resulted in green parts with a relative density of 57.1%—a representative value for BJ3DP processes that demonstrates effective parameter optimization. Subsequently, the green parts were sintered at 1800 °C for 9 h, resulting in a maximum density of 97.35%. The hardness of the as-sintered BJ3DP Cr parts was superior to that of samples produced by conventional levitation melting (184.20 HV vs. 171.20 HV). This work demonstrates that the no-heat printing strategy of BJ3DP effectively mitigates issues related to residual stress and cracking, providing a viable method for producing high-melting-point metallic materials. Full article

Clay 3D printing is an emerging field within additive manufacturing that presents significant opportunities for both structural and artistic applications. Driven by the increasing interest in this technology, there is a growing demand for optimized printing protocols tailored to clay, a readily available and versatile material. This study investigates the optimal processing parameters for kaolin clay composites and assesses the influence of clay-to-water ratios on the physical and mechanical properties of printed specimens. Experimental results demonstrate that higher clay content enhances the dimensional stability and structural integrity of printed components. The optimal formulation was determined to be 60% clay and 40% water, which produced the highest mechanical performance: the flexural strength of sintered specimens reached 1.3125 MPa and the compressive strength attained a maximum of 6.14 MPa. Shrinkage analysis indicated that specimens with greater water content experienced increased volumetric shrinkage, with reductions of up to 10% in linear dimensions and 14% in mass during drying and sintering. These findings highlight the critical relationship between material composition and final part performance in clay 3D printing and provide guidance for optimizing material formulations to enhance the mechanical robustness of printed clay composite structures for diverse applications. Full article

Selective Laser Sintering (SLS) is an Additive Manufacturing (AM) technology that is receiving considerable attention in the scientific and industrial communities due to its great ability to efficiently produce functional and complex parts. The present work aims to fabricate a real prototype via SLS, such as a hose reel for industrial applications, using polyamide 11 (PA11) as a starting material. Characterization of the PA11 powder properties was first carried out from a thermal and morphological viewpoint to determine the powder’s thermal stability by TGA, the sintering window and degree of crystallinity by DSC, and the microstructure by SEM, PSD, and XRD analyses. The results revealed that PA11 has a 45-micron average particle size, circularity close to 1, and a Hausner ratio of 1.17. Together, these parameters ensure that PA11 powder flows smoothly, packs uniformly, and forms dense and defect-free layers during the SLS process, directly contributing to high part quality, dimensional precision, and stable process performance. The printability of the PA11 was optimized for the realization of 3D-printed parts for industrial applications. Finally, the quality of the printed samples and the mechanical and thermal performance were investigated. Several PA11-based parts were fabricated via SLS, showing a high level of complexity and definition, ideal for industrial applications, as confirmed by the predominantly green areas of the colored maps of X-CT. A complete prototypal case for a hose reel was assembled by using the parts realized, and it was chosen as a technological demonstrator to verify the feasibility of PA11 powder in the production of industrial professional components. Full article

The PATCULT 3D project was developed during the 2024–2025 academic year as part of the Degree in Geoinformation and Geomatics at the University of Salamanca (Spain) as a service-learning initiative designed to integrate technical training with social commitment. The main objective was to provide students with practical experience in photogrammetry, 3D laser scanning, and additive manufacturing applied to the documentation and reproduction of cultural heritage. A particular feature of the project was its collaboration with the Spanish National Organization of the Blind (ONCE), placing accessibility for people with visual impairments as a central methodological tenet. Students developed tactile replicas of heritage assets from the province of Ávila, applying universal design principles and implementing Braille-based information systems to ensure fully inclusive modes of cultural engagement. In addition to the digital preservation of heritage, the activity reinforced students’ technical skills (covering data acquisition, 3D modeling, mesh refinement, and digital fabrication workflows) while fostering transversal competences such as teamwork, communication, critical reflection, and social awareness. The evaluation instruments demonstrated high levels of motivation and satisfaction, as well as a growing sensitivity to the social responsibilities of geomatics. The project is explicitly aligned with Sustainable Development Goals 4, 9, 10, and 11, thereby contributing to quality education, technological innovation, the reduction in structural inequalities, and the fostering of inclusive and sustainable communities. Overall, the experience illustrates how the integration of digital technologies with service-learning can strengthen academic training and, at the same time, generate measurable social value by making cultural heritage more accessible. Full article

This study investigates the influence of Fused Filament Fabrication (FFF) parameters on the properties of polyamide (PA, Nylon™) parts, which are valued for their excellent mechanical properties in additive manufacturing. The parameters examined include infill structure (diagonal and honeycomb), infill density (60%, 80%, and 100%), and sample orientation (0°, 45°, and 90°) relative to the build plate. Filaments from five manufacturers were tested, with injection-molded samples serving as references. Standard tensile strength tests were performed. The results indicate that the 0° orientation yielded the highest tensile strength, while the 45° and 90° orientations exhibited distinct behaviors associated with the geometry of additive manufacturing. The highest Young’s modulus was obtained for solid infill at 0° orientation. Although infill structure had a smaller effect, the honeycomb pattern provided more stable and superior mechanical properties at higher infill densities. The study compared filaments from different manufacturers, identifying two that met the tensile strength requirements for telerehabilitation device case prototypes. Full article

This research addresses the inherent limitations of low mechanical strength in FDM-printed materials by studying Carbon Fibre-reinforced Polylactic Acid (PLA-CF) composites. The low strength limitation of PLA-CF in FDM requires identifying the most suitable print angle and layer height parameters. This study maximises its structural robustness, filling a knowledge gap regarding its combined effect on tensile and flexural strength. The main objective was to find the best printing angle and layer height to improve mechanical performance, an important requirement for advancing additive manufacturing applications. A total of 210 FDM-printed specimens of the PLA-CF material were subjected to uniaxial tensile (ASTM D3039) and three-point bending (ASTM D790) tests, systematically varying the printing angles (0–90°) and layer heights of 0.1, 0.2, and 0.3 mm, following a full experimental design matrix. The ANOVA method has been used to determine the significant effect of factors on the established parameters. The findings indicated that both factors had a pronounced effect on the mechanical strength. Printing at lower angles (0° and 15°) provided, on average, greater resistance under tension (up to ~3920 N for a layer height of 0.1 mm), as well as under bending (up to 88.54 N for the same layer height), attributed to favourable fibre alignment and better load distribution. Conversely, higher angles (60° to 90°) drastically reduced strength (tensile failures due to delamination; bending forces as low as 30.02 N for a layer height of 0.3 mm, highlighting the weakness of perpendicular layer interfaces. Furthermore, lower layer height could result in better overall mechanical properties. In conclusion, FDM parameters with low print angles and reduced layer heights are essential for maximising the mechanical robustness and structural integrity of PLA-CF parts, enabling the identification of improved production processes for industrial applications and educational prototypes, among others. Full article

We report on the effect of hot isostatic pressing combined with solution and ageing treatment in different sequences on the mechanical properties of Inconel 718 specimens, which in turn have been fabricated by a hybrid additive manufacturing approach. The latter combines conventional laser powder bed fusion and in-situ high speed milling, yielding superior surface quality as being quantified by $R_{\mathrm{a}}$ about 1 μm. In a comparative study between hybrid additively manufactured parts and those built without milling, we find that, in general, any combination of heat treatment leads to a higher ultimate tensile strength and an improved endurance limit, while, however, hot isostatic pressing affects these figures of merit most. In addition, metallographic analysis reveals increased density and hardness for hot isostatic pressed parts due to precipitation hardening. These improvements of the mechanical properties are found to be even more pronounced when the printed parts are manufactured by the hybrid additive approach, i.e., for parts with improved surface conditions. Full article

Surplus out-of-spec Al powders, typically discarded, remain an underused resource. Their reuse via alternative consolidation routes is a sustainable path for AlSi10Mg alloy recycling, but studies on the feasibility of such routes remain scarce. This study proposes a novel route combining powder compaction (under 50 kN and 80 kN loads) and remelting/solidification via suction casting to assess the feasibility of producing dense parts with enhanced properties. Microstructure, mechanical properties (compression and Vickers microhardness), and tribological performance (ball-crater wear under dry and abrasive conditions) were evaluated. The proposed route produced dense AlSi10Mg parts with low porosity levels (≤0.2%) and refined dendritic microstructures (spacing between 2.4 and 4.6 µm). Increased cooling rates promoted microstructural refinement, while higher compaction loads improved densification. The refined microstructure samples achieved compressive strengths above 500 MPa. Remarkably, microstructural refinement led to significantly increased hardness, with values reaching ≥100 HV. The samples compacted at 50 kN and subjected to the highest cooling rate exhibited the lowest dry wear rate (2.3 × 10⁻⁴ mm³/N·m), comparable to additively manufactured AlSi10Mg (AM) samples, confirming the efficiency of this recycling route. The dry wear rates ranged from 2.3 to 3.9 × 10⁻⁴ mm³/N·m, reinforcing the inverse correlation between hardness and dry wear performance. Although abrasive wear resulted in a material loss approximately 3 times higher than dry wear, it preserved the same microstructural dependence: finer, harder, and denser samples exhibited better wear resistance. Full article

Sinter-based additive manufacturing (SBAM) processes, such as Cold Metal Fusion (CMF), combine the geometric freedom of additive manufacturing with the scalability of powder metallurgy, but part distortion and collapse during debinding and sintering remain critical design challenges. This study presents a revised stress-based optimization framework to address these issues by integrating sintering-specific load cases into topology optimization. In contrast to earlier approaches, the revised workflow applies all load cases to the upscaled green-part geometry. This adjustment mitigates the non-linear scaling effects of dead load-induced stresses. A Case study, including a steering bracket for a Formula Student racing car, demonstrates that the revised method improves not only sinterability but also application-related performance compared to earlier approaches. In addition, a semi-automated procedure for generating sinter supports is introduced, allowing stable processing of geometries without planar bearing surfaces. Experimental validation confirms that optimized supports effectively prevent part failure during post-processing, though challenges remain in separating complex freeform geometries. Finally, the influence of stiffness on sintering-induced deformations is investigated, showing that higher stiffness configurations significantly reduce dimensional errors. Together, these results highlight stress- and stiffness-based optimization as tools to enhance the reliability, efficiency, and design freedom of SBAM. Full article

In this paper, we present a mechatronic platform that must be used for the handling of thermally processed samples using laser equipment, after which it is cooled at low temperatures. In addition to the laser and cryogenic equipment, the mechatronic platform includes one robotic arm (with a new modular structure that allows it to adapt to different working places) for sample transfer between storage areas, a controlling system for the robotic arm based on a new haptic device with physical feedback, a laser system, a cryogenic system, and an optical thermal processing measurement system. A new VR application enables remote control of a robotic arm, ensuring user safety using a haptic device based on the VR model. We exemplified the process of manufacturing the parts for the robotic arm and glove using a 3D printing method. Full article

Electron beam melting (EBM) is an additive manufacturing method that enables the manufacturing of metallic parts. EBM-printed parts require post-processing to meet the surface quality and dimensional accuracy requirements. Machining is one approach that is beneficial for achieving these requirements. However, during machining, particles are emitted and can affect the environment and the operator’s health. This study aims to investigate the concentration of particles emitted during the milling of 3D-printed Ti6Al4V alloy produced by EBM. First, the influence of machining speed and cutting fluids, namely flood and minimum quantity lubricant (MQL), on particle emissions was statistically investigated. Then, the standby time required for the operator to safely open the machine door and interact with the machine within the machining area was studied. In this regard, two scenarios were proposed. In the first scenario, the machine door is open immediately after machining, and the operator waits until the particle concentration is acceptable. In the second, the machine door will be opened only when the particle concentration is acceptable. Statistical findings revealed that cutting fluids have a significant impact on particle emissions, exhibiting distinct patterns for both fine and coarse particles. Irrespective of the scenario, MQL results in higher particle concentration peaks and larger particle sizes, and the operator needs a longer standby time before interacting with the machine. For instance, the standby time in MQL is 328% more than that of the flood system. This study provides insight into sustainable manufacturing by taking into account social factors such as worker health and safety. Full article