Within the framework of the EuroFusion WPMAG project, an automatic laser-welding line was constructed to produce a 1 km long, empty stainless steel jacket demonstrator for the React & Wind (RW) conductor for EUDEMO. Four 500 m long C-profiles made of 316 L austenitic stainless steel were fabricated from similar to 8 m long sections using the manual TIG (Tungsten Inert Gas) welding method. A series of experimental investigations was carried out on the welded samples, including ferrite content measurements, microhardness tests, residual stress measurements, and shape deviation assessments. The results revealed that part of the austenitic structure transformed into ferromagnetic phase-ferrite-around the heat affected zone (HAZ), with up to 7% ferrite observed in the laser welds and up to 10% in the TIG welds. Due to the relative magnetic permeability of ferrite (mu(r) > 1), electromagnetic (EM) forces will be present in that region of the jacket during magnet operation. The microhardness measurements revealed an increased hardness in the welded region-up to 40.6%-due to material hardening and the presence of harder ferrite in the microstructure. Residual stresses were measured using the hole-drilling technique for both TIG and laser welds, revealing mostly compressive stresses in the TIG welds and tensile stresses in the laser welds. Considerable compressive stresses were introduced into the TIG welds during grinding. To assess the equivalent residual stress, a method of approximating the lower bound of the von Mises residual stress was proposed, revealing increasing values with the depth up to 1 mm, exceeding the initial yield stress at depths greater than 0.5 mm and reaching up to 425 MPa. The shape deviations around the TIG weld reached 0.41 mm, with deformations toward the centre of the wide side of the jacket, resulting in a concave shape. Such deviations are considerable and could impact subsequent assembly steps of the superconducting Cable-In-Conduit Conductor (CICC). This study presents a procedure for evaluating weld quality in conductor jackets, focusing on residual stresses, phase transformations, and welding-induced property changes.
This study presents the design, optimisation, and experimental evaluation of additively manufactured fittings for a custom helmet continuous positive airway pressure (hCPAP) system. The project was initiated as a rapid response to the shortage of respiratory support equipment during the COVID-19 pandemic. The inlet and outlet connectors of the helmet were redesigned to comply with the EN ISO 5356–1:2015 standard, reduce mass, and simplify assembly, while ensuring functional reliability and patient comfort. Components were fabricated using fused filament fabrication (FFF) and selective laser sintering (SLS) with medical-grade ABS, TPU-95A, and PA 2200 materials. A comprehensive assessment of material safety was performed, including tests for potential particle detachment under high-flow air conditions. Results confirmed that ABS Medical printed without active cooling exhibited no measurable release of microplastic particles, making it the preferred material for oxygen pathway components. Computational fluid dynamics (CFD) analyses guided the optimisation of the internal diffuser geometry, leading to improved air distribution and reduced perceived noise. The redesigned helmet system was evaluated in clinical trials involving 120 participants, demonstrating good ergonomic performance, low noise levels, and high user comfort. The findings validate additive manufacturing as a practical and reliable method for the small-batch production of medical fittings, particularly under emergency or resource-limited conditions. The proposed design approach highlights the potential of 3D printing to enable flexible, localised, and rapid development of medical devices adapted to current clinical needs.
In this paper, authors reported selected problems in friction stir welding (FSW) of 5 mm-thick AA7075-T651 and 3 mm-thick Ti6Al4V. The investigation involved macro and micro-structure analysis and mechanical testing. The welded joints of Ti6Al4V were characterized by the presence of backing plate steel fragments and tungsten particles in the bottom part of the stir zone (SZ) and thermo-mechanically affected zone (TMAZ), which resulted in a relatively low value of joint efficiency (60 %). The investigation on AA7075-T651 was concerned with high-speed FSW (HSFSW) using the MX Triflute tool. In all cases, defective welded joints have been obtained (incomplete root penetration, voids in the SZ) with the best result of joint efficiency of about 59 %.
In this article, the significance of additive manufacturing techniques in the production of vehicle parts over the past several years is highlighted. It indicates the industries and scientific sectors in which these production techniques have been applied. The primary manufacturing methods are presented based on the materials used, including both metals and non-metals. The authors place their primary focus on additive manufacturing techniques employing metals and their alloys. Within this context, they categorize these methods into three main groups: L-PBF (laser-powder bed fusion), sheet lamination, and DED (directed energy deposition) techniques. In the subsequent stages of work on this article, specific examples of vehicle components produced using metal additive manufacturing (MAM) methods are mentioned.
The material extrusion (MEX) method utilizing highly filled metal filament presents an alternative to advanced additive metal manufacturing technologies. This process enables the production of metal objects through deposition and sintering, which is particularly attractive compared to powder bed fusion (PBF) technologies employing lasers or high-power electron beams. PBF requires costly maintenance, skilled operators, and controlled process conditions, whereas MEX does not impose such requirements. This study compares research on 17-4 PH steel manufactured using two different commercially available techniques: MEX and powder bed fusion with laser beam melting (PBF-LB/M). This research included assessing the density of printed samples, analyzing surface roughness in two printing planes, examining microstructure including porosity and density determination, and measuring hardness. The conducted research aimed to determine the durability and quality of the obtained samples and to evaluate their strength. The research results indicated that samples produced using the PBF-LB/M technology exhibited better density and a more homogeneous structure. However, MEX samples exhibited better strength properties (hardness).
This paper aims to compare two ceramic materials available for additive manufacturing (AM) processes—vat photopolymerization (VPP) and material extrusion (MEX)—that result in fully ceramic parts after proper heat treatment. The analysis points out the most significant differences between the structural and mechanical properties and the potential application of each AM technology. The research revealed different behaviors for the specimens obtained via the two mentioned technologies. In the case of MEX, the specimens exhibited similar microstructures before and after heat treatment. The sintering process did not affect the shape of the grains, only their size. For the VPP specimens, directly after the manufacturing process, irregular grain shapes were registered, but after the sintering process, the grains fused, forming a solid structure that made it impossible to outline individual grains and measure their size. The highest compression strength was 168 MPa for the MEX specimens and 81 MPa for the VPP specimens. While the VPP specimens had half the compression strength, the results for the VPP specimens were significantly more repeatable.
Cementitious–glass composite bricks (CGCBs) with 3D-printed reinforcement structures made of PET-G could be an innovative production method that relies on recycling glass waste (78%) and PET-G (8%). These bricks offer a promising solution for the construction industry, which has a significant impact on climate change due to its greenhouse gas emissions and extensive use of natural aggregates. The approach presented in this article serves as an alternative to using conventional building materials that are not only costlier but also less environmentally friendly. The conducted research included mechanical tests using digital image correlation (DIC), utilized for measuring deformations in specimens subjected to three-point bending and compression tests, as well as thermal investigations covering measurements of their thermal conductivity, thermal diffusivity, and specific heat. The results highlighted the superior thermal properties of the CGCBs with PET-G reinforcements compared to traditional cementitious–glass mortar (CGM). The CGCBs exhibited a 12% lower thermal conductivity and a 17% lower specific heat. Additionally, the use of specially designed reinforcement substantially enhanced the mechanical properties of the bricks. There was a remarkable 72% increase in flexural strength in the vertical direction and a 32% increase in the horizontal direction.
An ongoing growth of the available materials dedicated to additive manufacturing (AM) significantly extends the possibilities of their usage in many applications. A very good example is 20MnCr5 steel which is very popular in conventional manufacturing technologies and shows good processability in AM processes. This research takes into account the process parameter selection and torsional strength analysis of AM cellular structures. The conducted research revealed a significant tendency for between-layer cracking which is strictly dependent on the layered structure of the material. Additionally, the highest torsional strength was registered for specimens with a honeycomb structure. To determine the best-obtained properties, in the case of the samples with cellular structures, a torque-to-mass coefficient was introduced. It indicated the best properties of honeycomb structures, which have about 10% smaller torque-to-mass coefficient values than monolithic structures (PM samples).
This study provides an alternative to traditional masonry materials: a cement-glass composite brick (CGCB), with a printed polyethylene terephthalate glycol (PET-G) internal scaffolding (gyroidal structure). This newly designed building material consists of 86% waste (78% glass waste, and 8% recycled PET-G). It can respond to the construction market's needs and provide a cheaper alternative to traditional materials. Performed tests showed an improvement in thermal properties after the use of an internal grate in the brick matrix, i.e., an increase in thermal conductivity (5%), and a decrease in thermal diffusivity (8%) and specific heat (10%). The obtained anisotropy of the CGCB's mechanical properties was much lower than the non-scaffolded parts, indicating a very positive effect of using this type of scaffolding in CGCB bricks.
The paper shows the results related to regeneration possibilities analysis of a damaged slider removed from a hydraulic splitter that was repaired using additive manufacturing (AM), laser-based powder bed fusion of metals (PBF-LB/M) technology. The results demonstrate the high quality of the connection zone between the original part and the regenerated zone. The hardness measurement conducted at the interface between the two materials indicated a significant increase equal to 35% by using the M300 maraging steel, as a material for regeneration. Additionally, the use of digital image correlation (DIC) technology enabled the identification of the area where the largest deformation occurred during the tensile test, which was out of the connection zone between the two materials.
In this study, the research on 316L steel manufactured additively using two commercially available techniques, Material Extrusion (MEX) and Laser Powder Bed Fusion of Metals (PBF-LB/M), were compared. The additive manufacturing (AM) process based on powder bed synthesis is of great interest in the production of metal parts. One of the most interesting alternatives to PBF-LB/M, are techniques based on material extrusion due to the significant initial cost reduction. Therefore, the paper compares these two different methods of AM technologies for metals. The investigations involved determining the density of the printed samples, assessing their surface roughness in two printing planes, examining their microstructures including determining their porosity and density, and measuring their hardness. The tests carried out make it possible to determine the durability, and quality of the obtained sample parts, as well as to assess their strength. The conducted research revealed that samples fabricated using the PBF-LB/M technology exhibited approximately 3% lower porosity compared to those produced using the MEX technology. Additionally, it was observed that the hardness of PBF-LB/M samples was more than twice as high as that of the samples manufactured using the MEX technology.
in this paper, the microstructure of laser beam welded sc-modified aa2519-F has been taken under investigation. The welded joint has been produced using Fanuc 710i industrial robot equipped with YLs-6000 6 kW laser beam source. The welding speed and laser power were equal to 0.75 m/min and 3.2 kW, respectively. The investigation involved microstructure observations with the use of both light microscope and scanning electron microscope with energy dispersive spectroscopy (eDs) analysis of chemical composition and microhardness distribution measurements. it has been stated that laser beam welding allows to obtain sc-modified aa2519-F weld of good quality, characterized by the presence of an equiaxed grain zone containing scandium-rich precipitates adjacent to the fusion boundary.
Machine learning (ML) is one of the artificial intelligence tools which uses past data to learn the relationship between input and output and helps to predict future trends. Powder bed fusion additive manufacturing (PBF-AM) is extensively used for a wide range of applications in the industry. The AM process establishment for new material is a crucial task with trial-and-error approaches. In this work, ML techniques have been applied for the prediction of the density of PBF-AM. Density is the most vital property in evaluating the overall quality of the AM building part. The ML techniques, namely, artificial neural network (ANN), K-nearest neighbor (KNN), support vector machine (SVM), and linear regression (LR), are used to develop a model for predicting the density of the stainless steel (SS) 316L build part. These four methods are validated using R-squared values and different error functions to compare the predicted result. The ANN and SVM model performed well with the R-square value of 0.95 and 0.923, respectively, for the density prediction. The ML models would be beneficial for the prediction of the process parameters. Further, the developed ML model would also be helpful for the future application of ML in additive manufacturing.
Additive manufacturing (AM) of spare parts is going to become more and more common. In the case of hydraulic solutions, there are also some applications of AM technology related to topological optimization, anti-cavitation improvements, etc. An examination of all available research results shows that authors are using specialized tools and machines to properly prepare AM spare parts. The main aim of this paper is to analyze the influence of quick repair of the damaged slipper-retainer from an axial piston pump by using an AM spare part. Hence, it was prepared with a 100-h test campaign of the AM spare part, which covers the time between damage and supply of the new pump. The material of the slipper-retainer has been identified and replaced by another material—available as a powder for AM, with similar properties as the original. The obtained spare part had been subjected to sandblasting only to simulate extremely rough conditions, directly after the AM process and an analysis of the influence of the high surface roughness of AM part on wear measurements. The whole test campaign has been divided into nine stages. After each stage, microscopic measurements of the pump parts’ surface roughness were made. To determine roughness with proper measurements, a microscopical investigation was conducted. The final results revealed that it is possible to replace parts in hydraulic pumps with the use of AM. The whole test campaign caused a significant increase in the surface roughness of the pump’s original parts, which was worked with the AM spare slipper-retainer: (1) from Ra = 0.54 µm to Ra = 3.84 µm in the case of two tested pistons; (2) from Ra = 0.33 µm to Ra = 1.98 µm in the case of the slipper-retainer. Despite significant increases in the surface roughness of the pump’s parts, the whole test campaign has been successfully finished without any damages to the other important parts of the whole hydraulic test rig.
This work investigates the effect of layer thickness on the microstructure and mechanical properties of M300 maraging steel produced by Laser Engineered Net Shaping (LENS®) technique. The microstructure was characterized using light microscopy (LM) and scanning electron microscopy (SEM). The mechanical properties were characterized by tensile tests and microhardness measurements. The porosity and mechanical properties were found to be highly dependent on the layer thickness. Increasing the layer thickness increased the porosity of the manufactured parts while degrading their mechanical properties. Moreover, etched samples revealed a fine cellular dendritic microstructure; decreasing the layer thickness caused the microstructure to become fine-grained. Tests showed that for samples manufactured with the chosen laser power, a layer thickness of more than 0.75 mm is too high to maintain the structural integrity of the deposited material.
With the development and popularization of additive manufacturing, attempts have been made to implement this technology into the production processes of machine parts, including gears. In the case of the additive manufacturing of gears, the availability of dedicated materials for this type of application is low. This paper summarizes the results of research on the implementation of 21NiCrMo2 low-alloy steel, which is conventionally used to produce gears as a feedstock in the PBF-LB/M process. The work presents research on the selection of process parameters based on porosity measurements, static tensile tests, and hardness measurements. In addition, the article includes a mathematical model based on the quadratic regression model, which allows the estimation of the percentage of voids in the material depending on the assumed values of independent variables (laser power, scanning velocity, and hatch distance). The paper includes a range of process parameters that enable the production of elements made of 21NiCrMo2 steel with a density of over 99.7%. Additionally, comparative tests were carried out on PBF-LB/M-manufactured steel (in the state after printing and the state after heat treatment) and conventionally manufactured steel in terms of its mechanical and microstructural properties. The results showed that the steel exhibited similar mechanical properties to other carburizing steels (20MnCr5 and 16MnCr5) that have been used to date in PBF-LB/M processes and it can be used as an alternative to these materials.
In recent years, additive manufacturing (AM) technologies, have been one of the fastest developing methods of production of various components. As far as building material is concerned, they allow for using not only polymers, but also composites or metals. Products fabricated using said technologies are used in various areas of industries, for instance in medicine, architecture, entertainment, and in particular in the construction of parts and components of machinery and equipment. To recognize and determine the products’ strength properties in a more comprehensive manner, 3D printing products used in mechanical applications are subject to various tests, e.g. static tensile test. This paper contains research about static torsion test on cylindrical samples made of high grade 20CrNiMo2-2 steel using the selective laser melting (SLM). Such an approach allowed to observe the material behaviour and to determine specific values of strength properties, such as the maximum tangential stresses in the material and bulk modulus of elasticity (shear modulus). The determination of such parameters allowed to compare them with the results of the tests carried out on components manufactured using other methods (e.g. a cold drawn solid bar sample).
The fundamental aim of the research is to investigate the microstructure and mechanical properties of the AA2519-T62 laser beam welded joints obtained with various values of welding velocity. For the constant value of laser power (3.2 kW) three joints have been produced with various values of welding velocity: 0.8, 1.1, and 1.4 m/min. The joints have been subjected to microstructure analysis (including both light and scanning electron microscope), microhardness measurements, tensile tests, and fractography of tensile samples. The established values of joint efficiency contain within the range of 55-66% with the highest value (66%) reported for the joint obtained with 1.1 m/min welding velocity. The produced welds have noticeable participation of pores, which tends to increase together with the value of welding velocity. In all cases, the failure has occurred in the fusion zone by ductile fracture.
The significant growth of Additive Manufacturing (AM), visible over the last ten years, has driven an increase in demand for small gradation metallic powders of a size lower than 100 µm. Until now, most affordable powders for AM have been produced using gas atomization. Recently, a new, alternative method of powder production based on ultrasonic atomization with melting by electric arc has appeared. This paper summarizes the preliminary research results of AM samples made of two AISI 316L steel powder batches, one of which was obtained during Ultrasonic Atomization (UA) and the other during Plasma Arc Gas Atomization (PAGA). The comparison starts from powder particle statistical distribution, chemical composition analysis, density, and flowability measurements. After powder analysis, test samples were produced using AM to observe the differences in microstructure, porosity, and hardness. Finally, the test campaign covered an analysis of mechanical properties, including tensile testing with Digital Image Correlation (DIC) and Charpy’s impact tests. A comparative study of parts made of ultrasonic and gas atomization powders confirms the likelihood that both methods can deliver material of similar properties.