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The implementation of sustainable production patterns in the sense of a circular economy is becoming increasingly important due to the rising consumption of resources. In addition, remanufacturing enables the technological sovereignty of company locations. The aim of remanufacturing is to return used products to the market in an as-new or even better condition than initial new products. To achieve this, flexible, semi-autonomous production is needed, which requires a coordinated, adaptable production system. This can be achieved by combining additive manufacturing (AM) and machining. Powder-based high-speed directed energy deposition using a laser beam (DED-LB) is particularly suitable for this application. High-speed DED-LB enables multifunctional structures and the combination of multiple metal powders in a single component. In addition, by specifically influencing the cooling rates, high-speed DED-LB is capable of producing metal parts with high hardness and high strength. Modern DED-LB systems include 5-axis features, allowing material to be applied to irregular geometries. To unlock the full potential of the DED-LB process, suitable process parameters for thick- and thin-walled components must be derived. Therefore, the relationship between process parameters, resulting geometries and process influences on microstructure must be known. This will help to overcome technical challenges such as repeatability and quality, as well as difficulties caused by cumulative defects, and create a basis for reliable reprocessing in the sense of a circular economy. Peer review under the responsibility of the scientific committee of the 10th CIRP Conference on Asssembly Technology and Systems [ABSTRACT FROM AUTHOR]

Hairpin technology has recently become the predominant winding technology for the manufacturing of stators used in electric traction motors. In contrast to conventional winding techniques, the manufacturing process chain is based on rectangular wire which is bent into a three-dimensional U-shape – so-called hairpin coils. These hairpin coils have to be individually gripped and assembled to form the stator winding. There can be hundreds of hairpin coils in a single stator, which can also differ in shape. Therefore, gripping and moving the individual hairpin coils is a challenging task in terms of flexibility and cycle time. This paper presents an approach to meet the outlined requirements using additively manufactured vacuum grippers. A concept is investigated in which the vacuum is generated in a conventional vacuum ejector and fed to the vacuum gripper via hose lines. In contrast, the concept of a functionally integrated vacuum gripper manufactured by a new laser-sintering process with automated continuous fibre reinforcement is presented. Based on the laser-sintering process, a lightweight vacuum gripper with an integrated vacuum ejector can be manufactured in a single process step without additional costs for purchased parts. After a review of the state of the art in both hairpin-specific and additively manufactured lightweight grippers, experimental test series are carried out concerning the vacuum quality and the grip strength of the different vacuum gripper designs. Pull-off tests show that high holding forces of several Newtons are possible proving the basic usability of vacuum grippers for hairpins, even though the achievable vacuum quality of the functionally integrated vacuum gripper is lower than that of the conventional ejector. Comparison of the novel approaches with a conventional mechanical hairpin gripper regarding weight, production costs and production time show promising improvements. [ABSTRACT FROM AUTHOR]

The hype around additive manufacturing technologies suggests that any complex shaped structure can be fabricated regardless of the type of material used. Moreover, it is often suggested that additive manufacturing processes will certainly disrupt the supply chain logistics and that everyone will be able to print on the demand at the comfort of their home. In this viewpoint, we describe and demystify some of the common assumptions associated with these set of technologies. We also show that conventional manufacturing processes cannot be fully replaced by additive manufacturing technologies, but rather there is a need for a complementarity between well-consolidated manufacturing technologies and additive manufacturing. While some of the contents presented here are basic for specialists working in the manufacturing field, we expect that this viewpoint can aid researchers working on topics related to additive manufacturing, but with less focus on the manufacturing aspects, helping them understand the actual limitations and advantages associated to these technologies. The four key issues that are addressed in this viewpoint, and their consequences, also intend to shape and mold future entrepreneurial efforts on additive manufacturing, as well as define future impacts (environmental, logistics, commercial and disruptive) associated to additive manufacturing technologies. [ABSTRACT FROM AUTHOR]

Directed Energy Deposition (DED), a metal additive manufacturing technique, shows promise for future orthopaedic applications, especially in bone plate manufacturing. The need for patient-specific solutions in orthopaedics is growing, driven by the limitations of traditional bone plates made from stainless steel or titanium alloys and the rising incidence of complex fractures. This paper explores the design of orthopaedic bone plates using Generative Design (GD) and Topological Optimization (TO), aimed at eventual production through DED. By focusing on design, the research addresses challenges like stress shielding, caused by the modulus disparity between conventional plate materials and natural bone. Significant findings include mass reductions of 43.7% and 44.2% for GD designs GD1 and GD2, respectively, and a 36% reduction for the TO design TO1, enhancing biomechanical performance with improved strain values. The findings demonstrate GD's effectiveness in generating anatomically congruent implants, showcasing advancements in personalized care and fracture treatment. The integration of GD and DED within the Design for Additive Manufacturing (DfAM) framework offers a promising pathway for future research focused on refining patient-specific designs and manufacturing processes, aligning with the evolving needs of orthopaedic treatments. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) recently appeared as an alternative to thermoforming for medical corset production, enabling lighter, more breathable, and highly customizable designs by creating complex shapes and adjusting material properties. However, the common 3-axis architecture of AM machines limits corset performance due to the unidirectional layering of material. As an alternative, a method involving radial material deposition on a rotating substrate is being explored. In this setup, the substrate's shape becomes a key factor in reducing manufacturing time and cost, directly impacting the needed volume support between the substrate and the corset. In order to avoid the time and material-intensive practice of creating a new substrate for each corset, the objective is to use a limited number of reusable substrates specific to morphological categories of corsets. A four-step method for generating optimally shaped substrates is proposed. Firstly, unsupervised classification of 3D patient scans sorts them into fixed morphological categories. After achieving the optimal 3D alignment of the scans per category, substrates can be generated from the resulting minimal surfaces. A validation process involving fitting each scan to each categorized substrate and then calculating the resulting intervolume demonstrates the potential to reduce support volume in the additive manufacturing of a morphological class of corsets. [ABSTRACT FROM AUTHOR]

Recent innovations in Drug-Eluting Stents (DES) technology have led to the development of new stents with further reduction in strut width, the ultrathin DES, with struts thinner than 70 µm. Ultrathin DES may further improve the efficacy and safety profile of Percutaneous Coronary Intervention (PCI) by reducing the risk of target-lesion and target-vessel failures compared to the current-generation DES. However, the ultrathin DES metallic platform still presents some associated problems, such as biofilm formation, infection, and migration, all related to the cellular response. The present work aims to produce an ultrathin permanent polymeric platform for a new generation of polymeric drug-eluting stents (PDES). In this work, the cellular response was compared with the traditional stainless steel (SS316L) and polycaprolactone (PCL) to determine whether these polymers could address this challenge. An innovative method of tubular 3D micro stereolithography tubular (ST3DT) was used. Different PDES platforms were fabricated with different polymeric materials (based on polyurethane and urethane dimethacrylate). Subsequently, HFL1 fibroblasts were seeded on the PDES, PCL and SS316L for 3 days. The findings from the assays of cell biocompatibility and proliferation (75%PCL), coupled with the successful fabrication of stent struts below 70 µm using the Surgical Guide resin and the ST3DT method, suggest that resin is a promising candidate for a PDES. [ABSTRACT FROM AUTHOR]

Biomedical engineering relies on topology optimization to refine material distribution, crucial for lightweight, high-performance prostheses and orthoses. Advanced manufacturing techniques like additive manufacturing can then be used to create these intricate designs layer by layer, ensuring precision and customization. However, conventional numerical simulation-based topology optimization methods can be time-consuming and resource-intensive, especially as the design domain expands. To overcome this issue, machine learning models are investigated for their ability to perform topology optimization. The results indicate a significant decrease in computation time, along with comparable optimization performance to conventional methods. [ABSTRACT FROM AUTHOR]

Melt electrowriting (MEW) has become a novel technique for textile (scaffold) biomanufacturing of Tissue Engineering scaffolds which, once they are combined with cells, we refer to them as biotextiles. The accuracy of weaving resorbable polymer fibers provides paradigmatic advances over electrospinning. This innovation in MEW allows control of pore geometry, mechanical properties, and overall geometries, especially the ability to bring two thin membranes formed from different, complementary types of cells as occurs in the key areas of most tissues. The biofabrication of large surfaces (i.e., high surface areas) where two or more types of cells are in very thin membranes in direct contact is unprecedented. One of the main challenges is to learn how to tame the MEW process parameters to biomanufacture personalized textiles with geometries other than the scaffolds produced with the well-demonstrated flat sheet and straight tube collectors. Why? Because no tissue within the human body takes the form of a flat sheet or straight tube. In this work, we show the challenges involved in translating MEW to the printing of textiles with out-of-plane geometries and validated a promising multi-axis kinematic strategy to orthogonally aligned the printing nozzle to them. Of particular interest to us is the effect of the fiber collector geometry on the electric field (i.e., inhomogeneities not seen with flat sheet and straight tube collectors) and thus in fiber deposition accuracy. The benefit of applying multi-axis CAM methodologies and the use of a digital twin to assist in MEW biomanufacturing is also validated. We believe these advances will unleash the imagination of people working with MEW for novel applications in Regenerative Medicine. [ABSTRACT FROM AUTHOR]

The interest in Nitinol (NiTi) as biomedical material is growing thanks to its unique properties, particularly shape memory and superelasticity. Recently, additive manufacturing (AM) has emerged as an alternative to fabricate superelastic NiTi biomedical parts. However, when using AM to fabricate NiTi parts, a proper heat treatment must follow, recommended not only to alleviate the AM-induced residual stresses, but also to develop a suitable microstructure to enhance the material superelasticity. This heat treatment is expected to modify also the NiTi corrosion behavior, which must be evaluated since corrosion may lead to the possible harmful release of nickel ions in the human environment. In this framework, the objective of the paper is to assess the mechanical and corrosion properties of a Ni-rich NiTi fabricated by laser powder bed fusion before and after heat treatment. To this aim, nano-indentation was used to evaluate superelasticity, whereas electro-chemical tests provided the corrosion potential and current density. The results of the analyses show that both the mechanical and corrosion characteristics were related to the peculiar microstructural features induced by the AM and heat treatment steps, nevertheless ageing at 600°C was the best in terms of superelasticity, while aging at 300°C assured the highest corrosion resistance. [ABSTRACT FROM AUTHOR]

This work aimed to redesign a personalized prototype of an external breast prosthesis using additive manufacturing technology. The primary objective was to develop a prosthesis capable of closely simulating the deformation characteristics of a natural breast while adhering to the principles of Hooke's law and being able to withstand the pressures exerted by typical bras. To achieve this, a detailed 3D scan of a volunteer's breast was employed as the foundation for the prosthesis model. Multiple prototypes were crafted, each utilizing a gyroid structure with varying fill percentages, including 5%, 7.5%, 10%, and 25%. Comprehensive compression tests were conducted following ASTM D1621 standards. The results indicated that the 7.5% fill percentage prototype exhibited superior deformation properties under less applied pressure. Furthermore, extensive design evaluations were conducted to optimize 3D printing parameters and minimize the need for internal printed supports. This work underscores the potential of additive manufacturing as a promising technique for producing external breast prostheses that offer functional support and prioritize comfort and natural aesthetics. [ABSTRACT FROM AUTHOR]

This paper describes development of multi-layer deposition of Ti6Al4V added with 5 at% of Cr, 5 at% of Ni, and 2.5 at% of each Cr and Ni by μ-plasma powder arc additive manufacturing process. It presents findings on their microstructure, porosity, evolution of phases, microhardness, tensile strength, ductility, fracture morphology, fracture toughness, and abrasion resistance. Phase evolution found that α/α'-Ti and β-Ti phases are formed in all the alloys, intermetallic phase Cr 2 Ti evolved in Ti6Al4V5Cr and Ti6Al4V2.5Cr2.5Ni alloys whereas intermetallic phase Ti 2 Ni is formed in Ti6Al4V5Ni alloy. Their microstructure revealed that addition of chromium and nickel refined grains of their α-Ti and β-Ti phases. Elemental composition of the evolved phases found that at% of chromium, nickel, and vanadium in β-Ti phase is more than the α-Ti phase of the developed alloys. It enhanced their ultimate tensile and yield strength, and microhardness but reduced ductility. It changed the fracture mode from ductile to a combination of ductile and brittle mode possessing large size dimples, micropores, and cleavage facets. It is due to solid solution strengthening, evolution of intermetallic phases Cr 2 Ti and Ti 2 Ni, and grain refinement of β-Ti and α-Ti phases. Enhanced microhardness and presence of intermetallic phases improved fracture toughness and abrasion resistance of the developed alloys thus imparting them higher resistance to propagation of cracks and abrasive wear. [Display omitted] • Addition of Cr and Ni to Ti6Al4V alloy increased yield and ultimate tensile strength but reduced ductility. • The additional elements increased fracture toughness, microhardness, abrasion resistance. • The additional elements changed fracture mode to ductile and brittle with micropores and cleavage facets. • The additional elements refined grains of α-Ti and β-Ti phases. • β-Ti phase of Ti6Al4VxCryNi alloy has more at% of Cr, Ni and V than their α-Ti phase. [ABSTRACT FROM AUTHOR]

Due to the poor surface characteristics of additively manufactured parts, the necessity for post-process surface enhancement is crucial. Among the prevalent post-processing techniques, the acoustic cavitation-based surface finishing technique has recently emerged. Despite a considerable amount of focused research on the material removal mechanisms of this technique, less attention has been devoted to addressing its limitations associated with enhancing the process capability towards achieving a better surface finish. The driving force behind the acoustic cavitation technique is the bubble implosion through cavitation streaming, and the cessation of the acoustic cavitation streaming beyond a certain length is the main limitation. It has restrained the process capability towards finishing both external and internal surfaces. Hence, this research aims to unravel novel ways of employing the acoustic cavitation-generating parameters and achieving better-quality surface finishing of additively manufactured (AM) components. A study has been conducted on different AM materials, including Inconel 625 and aluminum alloy, by introducing various methods associated with acoustic amplitude, working mediums, temperature, and external vibration. The results reveal a significant reduction in average surface roughness for both materials. The topographical and morphological observations confirm the qualitative improvement on the surfaces. In addition, the conical bubble structures that frame the acoustic cavitation streaming are elucidated by implementing high-speed imaging techniques, and their enhancement at different parametric conditions is delineated. Henceforth, the findings suggest a notable insight into the potential of the employed approaches in enhancing the acoustic cavitation streaming for achieving a better surface finish of AM components. [Display omitted] • Surface finishing of AM components by enhanced acoustic cavitation. • Overcoming the limitations of acoustic cavitation for surface quality improvement. • Acoustic cavitation: factors affecting acoustic streaming and AM surface quality. • Thermal effect on bubble structures in free-field and confined acoustic cavitation. • A study on parametric investigation of acoustic cavitation: a different approach. [ABSTRACT FROM AUTHOR]

Lattice structures to fabricate bone implants can avoid stress-shielding effects and promote bone-in-growth. However, the performance of bones varies in different body parts, creating a barrier to manufacture an appropriate lattice structure for bone implant. Here, the formability, anisotropy, energy absorption abilities, stress distribution, and deformation mode of the laser powder bed fusion (LPBF) processed face-centered cubic (FCC), Octet, and Kelvin lattice structures were systematically compared through experiments and finite element analysis. The results show that the Kelvin lattice structure had the optimal comprehensive mechanical performance. This research has potential value for the design and manufacturing of specific bone implants. [ABSTRACT FROM AUTHOR]

Arc weaving is a feasible technique for making thick-walled components in the arc-based directed energy deposition process (DED-Arc). In the current study, four different arc weaving strategies, namely, triangle, square, semi-circle, and helix, are used to fabricate the walls. For this, gas tungsten arc welding (GTAW) based DED-Arc set-up using aluminium alloy wire (ER4043) as a filler material is used for different printing strategies. The fabricated walls were investigated for their surface characteristics, microstructure, mechanical properties and residual stress. The weld-bead and wall geometry study revealed that for the same number of layers, the semi-circular arc-weaving strategy had the maximum height among all, with an effective area of 65.77 %. The waviness of the side surface of the walls was maximum for the semi-circle (714 ± 35 µm), indicating the semi-circle will require almost twice the amount of machining than the helix, square, and triangle in postprocessing operation. The optical micrographs showed that the semi-circular weaving pattern exhibited a coarser gain with thicker grain boundaries with an average grain size of 46.4 ± 23.7 µm as compared to other weaving patterns. The triangle weaving pattern demonstrated the smallest grain size among all, resulting in high hardness and superior wear resistance. The residual stress (RS) results revealed that the RS is in tension (22–24 MPa) in the bottom layers for all the walls and becomes almost zero (−1.5 to −2.5 MPa) in the top layers except for the walls formed by helix strategy. The square weaving strategy strikes a balance between surface characteristics, microstructure, and mechanical properties, making it a highly viable option for thick wall fabrication. [Display omitted] [ABSTRACT FROM AUTHOR]

Irregular (i.e. non-spherical) morphology powder is more cost-efficient to produce than spherical shaped powder. However, its reduced levels of flowability limit the wide application ranges of laser beam powder bed fusion (LPBF). To address this issue, a novel powder sheet additive manufacturing concept (MAPS) is proposed. Herein, a pre-manufactured metal particle-polymer binder composite (i.e. powder sheet) feedstock is employed as a raw material. The printability of irregularly shaped powder particles in sheet (MAPS) format was physically investigated using a range of different process parameters. The manufacturing process was observed by high-speed imaging. Microstructural and chemical element characterisations of the irregularly shaped powder particle print were then compared against those prints which were conducted using sheet-based (MAPS) spherical powder morphologies. The results indicated that the geometric accuracy and density of irregular powder morphology sheet printing improved when using a negative defocus strategy of the laser beam. A negative defocusing strategy allowed for the melting mode of the material to be transformed from keyhole to a more favourable conduction state. High speed imaging revealed that more spatter and vapour plume were observed with the increase in the magnitude of the negative defocus. The multi-morphology 304 L stainless steel (SS304) samples were printed in a single printer using an efficient method for the first time, i.e. printing spherical SS304 material on top of irregular SS304. EDX results indicated an insignificant change of chemical elements between the spherical and irregular prints. EBSD results revealed that columnar grains could grow through the irregular-spherical transition zone and similar grain size can form between spherical and irregular prints. The results of this study provide insights into the optimum printing configurations for powder sheet additive manufacturing using a cost-effective solution of irregular morphology material. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM), often referred to as 3D printing, is a manufacturing technique that involves the creation of complex objects layer-by-layer while providing design flexibility. The broad spectrum of additive manufacturing applications in aerospace, medicine, automotive industries, etc., using high-value materials necessitates a precise final product with minimal wastage. However, the print's dependence on optimizing parameters such as nozzle diameter, printing speed, extrusion speed, nozzle temperature and other multifaceted factors can contribute to deviations from the intended design. This paper introduces a closed-loop in-situ assessment of layer height deviations using point cloud data to ensure real-time printed part modification. The printing is done using a direct-fed pellet screw extruder mounted on top of 6 degrees of freedom robotic arm. A structured light 3D scanner is used to obtain point cloud data. A Robot Operating System (ROS) based digital toolchain is employed to have seamless communication between all nodes of the AM system. The layer-by-layer printing is observed using an in-house CAM solution, which examines the point cloud data and compares it to the original CAD model. The deviations are analyzed, and the path of the next layer is re-planned to adjust for the digression in the previous layer. This control loop ensures that the final product meets the desired quality standards at minimum cost and efficient time and increases the opportunity for rapid prototyping and iterative design improvements. [ABSTRACT FROM AUTHOR]

The dependencies between process parameters and the resulting geometrical accuracy of additively manufactured parts are usually highly non-linear and thus complex to investigate and mathematically quantify. Therefore, the application of artificial intelligence techniques is promising to generate mathematical models that reduce effort and increase the prediction quality. The overall goal is to establish a procedure to automatically determine the optimal settings of the manufacturing process parameters to guarantee the highest geometrical accuracy of parts in additive manufactured production. This paper presents the first step towards this fully automatic procedure – the training and evaluation of a mathematical model based on artificial neural networks to quantify the effects of varying process parameters of a material extrusion process on both macro- and micro-geometrical performances. Therefore, a dataset is established based on the Design of Experiment of an additively manufactured part made from Polylactic Acid filament. The dataset is then used to train an artificial neural network that predicts the dimensional and micro-geometrical deviations of the manufactured parts. Finally, the evaluation of the network's prediction quality and reliability indicate that it is possible to predict the parameters linked to resulting print quality with a mean absolute error from 0.0004 to 0.036. [ABSTRACT FROM AUTHOR]

Directed energy deposition (DED) is an additive manufacturing technique that is very well adapted for remanufacturing metallic components. The process works by depositing material onto either a substrate or, in the case of remanufacturing, existing component using a metal wire or powder that is fed into an energy source, usually either a laser or electron beam. DED naturally introduces a large amount of heat into the component in a manner that generally produces both large and sharp temperature gradients. These gradients generate residual stresses in the material which cause the component to warp in ways that are often difficult to accurately predict. To use this method for remanufacturing components with specific geometrical demands, such as turbine blades, any potential warping must be accounted for and minimized. A simulation methodology based on inherent strain (IS) is proposed as a high-throughput high accuracy method of evaluating the warping based on the geometry and parameters of an individual component. The study compares the results of this high throughput IS-based simulation tool with more traditional thermomechanical simulations with respect to both accuracy and time efficiency when applied to an industrial case. [ABSTRACT FROM AUTHOR]

Compared with traditional machining processes, additive manufacturing (AM) has received widespread attention in recent years because of its high degree of modeling freedom. However, due to the multiple manufacturing errors and complex physical state changes involved in the process, the geometric deviation on the AM part surface is a challenge for controlling product geometrical quality. To address this problem, data-driven machine learning (ML) techniques have been widely studied in product quality controlling. However, traditional ML greatly depends on the training sample data, and suffers the risk of violating physical mechanisms due to the lack of domain knowledge. In order to take the best advantage of domain knowledge, prior information and deep learning algorithm, this paper proposes a knowledge-integrated deep learning algorithm and constructs the geometric deviation prediction model of the AM part surface. After that, the method was verified with design of experiments. The results show that compared with the data-driven neural network (DDNN), the knowledge-integrated neural network (KINN) has fewer iterations during the training process, less sample data requirement and more accurate prediction results. [ABSTRACT FROM AUTHOR]

To enhance the energy absorption characteristics of the energy-absorbing structure in metal alloy 3D printing, various heat treatment conditions were studied on the 3D printed hourglass multi-cellular energy-absorbing structure (HTMEAS). The results reveal that as the annealing temperature rises, the structural morphology of the α-Al+Si phase in AlSi10Mg alloy undergoes alterations, particularly when the annealing temperature remains below 300°C. After heat treatment, the HTMEAS can contract layer by layer along the gradient and undergo controllable and orderly deformation. The maximum energy absorption, displacement, and peak force reached 758 J, 30 mm, and 30 kN, respectively.These values represent a significant enhancement of 146.8 %, 157.8 %, and 50 % compared to those without heat treatment, showcasing commendable mechanical properties. This advancement establishes a solid theoretical framework and assurance for the future development and refinement of 3D printing energy-absorbing structures. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Taibah University Medical Sciences is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Afyon Kocatepe University Journal of Science & Engineering / Afyon Kocatepe Üniversitesi Fen Ve Mühendislik Bilimleri Dergisi is the property of Afyon Kocatepe University, Faculty of Science & Literature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The growth of 3D construction printing needs appropriate integration into the planning and execution phases of building projects. With this aim, the Architecture, Engineering, and Construction sector (AEC) has been increasingly adopting building information modeling (BIM) systems to synchronize design and construction processes. This study proposes a technical workflow to manage 3D construction printing into BIM models, evaluating various procedures according to construction element features. Based on mature software platforms, the research details the data transfer process using a case study of a single-story home. The case delves into design procedures for constructing walls of varied shapes, adjustments in width, joints, openings, textures, fillings, and the insertion of reinforcements and services while also discussing requirements of other building elements. Work steps for managing design information and controlling printing machines are described. The study's outcome presents a comprehensive information flow, encompassing model segmentation, geometric data transfer, adjustments of details, and the generation of printing paths. Then, it is offered a discussion that underlines the importance of a synergistic digital information flow that merges both design and execution phases, promoting construction efficiency and the embrace of innovative technologies. The contribution of the paper focuses on technical design strategies for 3D construction printing, but also on suggesting an integrated process. [ABSTRACT FROM AUTHOR]

This study presents a scientometric analysis focusing on fused deposition modeling (FDM), highlighting key findings such as the top contributing nations, prevalent publication types, and prominent publishers. It tracks changes in FDM research over time, noting a significant increase in publications, and identifies popular keywords indicating recurring topics in the field. Additionally, the analysis explores highly cited journals and their burst rates, concluding with an examination of research categories and institutes involved in FDM research. These insights offer valuable guidance for researchers, institutions, and stakeholders interested in advancing FDM technology, with practical implications discussed. The detailed examination of the scholarly landscape in FDM contributes to a deeper understanding of the field's dynamics and potential avenues for future research and innovation. [ABSTRACT FROM AUTHOR]

Purpose: This review aims to summarize the available technologies, material categories, and prosthodontic applications of additive manufacturing (AM) dental ceramics, evaluate the achievable accuracy and mechanical properties in comparison with current mainstream computer-aided design/computer-aided manufacturing (CAD/CAM) subtractive manufacturing (SM) methods, and discuss future prospects and directions. Study selection: This paper is based on the latest reviews, state-of-the-art research, and existing ISO standards on AM technologies and prosthodontic applications of dental ceramics. PubMed, Web of Science, and ScienceDirect were amongst the sources searched for narrative reviews. Results: Relatively few AM technologies are available and their applications are limited to crowns and fixed partial dentures. Although the accuracy and strength of AM dental ceramics are comparable to those of SM, they have the limitations of relatively inferior curved surface accuracy and low strength reliability. Furthermore, functionally graded additive manufacturing (FGAM), a potential direction for AM, enables the realization of biomimetic structures, such as natural teeth; however, specific studies are currently lacking. Conclusions: AM dental ceramics are not sufficiently developed for large-scale clinical applications. However, with additional research, it may be possible for AM to replace SM as the mainstream manufacturing technology for ceramic restorations. [ABSTRACT FROM AUTHOR]

• The optimized full liquid phase sintering is investigated for binder jetting printed Mg alloy. • The Y and Nd in WE43 powder film contributes to keeping the shape during sintering. • The full liquid phase sintering exhibits a significantly reduced sintering time and low porosity. • The final sintered WE43 alloy products display superior corrosion resistance and mechanical properties. This study investigates full liquid phase sintering as a process of fabrication parts from WE43 (Mg-4wt.%Y-3wt.%RE-0.7wt.%Zr) alloy using binder jetting additive manufacturing (BJAM). This fabrication process is being developed for use in producing structural or biomedical devices. Specifically, this study focused on achieving a near-dense microstructure with WE43 Mg alloy while substantially reducing the duration of sintering post-processing after BJAM part rendering. The optimal process resulted in microstructure with 2.5% porosity and significantly reduced sintering time. The improved sintering can be explained by the presence of Y 2 O 3 and Nd 2 O 3 oxide layers, which form spontaneously on the surface of WE43 powder used in BJAM. These layers appear to be crucial in preventing shape distortion of the resulting samples and in enabling the development of sintering necks, particularly under sintering conditions exceeding the liquidus temperature of WE43 alloy. Sintered WE43 specimens rendered by BJAM achieved significant improvement in both corrosion resistance and mechanical properties through reduced porosity levels related to the sintering time. [Display omitted] [ABSTRACT FROM AUTHOR]

• To review on development of magnesium and its alloys. • To investigate multiple biomedical applications of magnesium-based materials including orthopedic implants, cardiovascular implants, biodegradable surgical wires, staplers, and their anti-tumor activity. • To explore magnesium alloys functional properties such as biocompatibility, density, mechanical properties, corrosion resistance in biomedical environment, ductility, nontoxicity, host tissue response, and various anti-microbial strategies. • To peruse different surface modification and advanced manufacturing technologies of magnesium and its alloy to improve biomedical properties. • To survey magnesium and its alloy for biomedical applications and future direction. Magnesium (Mg) and its alloys have recently gained increasing attention in the biomedical field as promising biodegradable materials with harmless degradation products. Magnesium-based alloys have a wide range of biomedical applications because of their outstanding biocompatibility and unique mechanical properties. Widespread use of Mg-based biomedical devices eliminates the need for post-healing biomaterial removal surgery and minimizes the negative consequences of the implantation of permanent biomaterials, including stress shielding and undesired metal ion release in the body. This paper provides a literature review on the properties and manufacturing methods of Mg-based alloys for biomedical applications, including orthopedic implants, cardiovascular applications, surgical wires and staplers, and antitumor activities. Each application of Mg-based biomaterials is investigated from a biological perspective, including matching functional properties, biocompatibility, host tissue responses, and anti-microbial strategies, along with potential additive manufacturing technologies for these applications. Finally, an outlook is presented to provide recommendations for Mg-based biomaterials in the future. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper presents a multidisciplinary design methodology for a single-stage radial compressor of a small-scale gas turbine jet engine. The entire engine, producing more than 600 N thrust with an engine diameter of less than 30 cm, will be manufactured by additive manufacturing (AM) in a single piece. Therefore, it is crucial to pinpoint the design limitations that may arise due to the AM methods. The preliminary design calculations are carried out in the Von Karman Institute for Fluid Dynamics (VKI's) in-house centrifugal compressor off-design (CCOD) code. The detailed design and optimization studies coupled with computational fluid dynamics (CFD) simulations are performed to improve the aerodynamic performance of the radial compressor by using the sequential quadratic programming (SQP) method with an Adjoint solver in the VKI's in-house computer aided design and optimization (CADO) tool. In the final design, a large increase in thrust is obtained and the manufacturing constraints are satisfied. [ABSTRACT FROM AUTHOR]

In this study, ultrasonic nanocrystal surface modification (UNSM) was employed to process 316L stainless steel fabricated using selective laser melting (SLM). The surface integrity, microstructure evolution, and mechanical behavior of this alloy before and after UNSM treatment were systematically characterized. The results show that the surface integrity and wear resistance of the alloy has been significantly improved due to the synergistic effect of grain refinement, work hardening, and beneficial compressive residual stresses that resulted from UNSM processing. The effect of the gradient structure and residual stress introduced by UNSM processing on the strengthening mechanism and its effect on friction and wear behavior have been discussed. The improved surface finish, the grain refinement layer, and the presence of compressive residual stress of the UNSM SLM 316L stainless steel alloy successfully demonstrated UNSM to be a promising post-processing surface treatment technology to enhance the fatigue performance of additively manufactured metallic materials. [ABSTRACT FROM AUTHOR]

Additive Manufacturing (AM) is vital for industrial innovation, offering high potential for groundbreaking solutions. However, its successful implementation still depends on overcoming several challenges. Particularly, the assessment of surface integrity in AM-generated components, and its degradation when subjected to contact stresses presents an ongoing endeavor. Within this context, the current work delves into the study of the surface integrity of 20MnCr5 case-hardened samples manufactured through laser powder bed fusion (L-PBF), as well as delves into the investigation of surface failure progression when the samples are subjected to cyclic contact stresses. This study encompasses the analysis of residual stresses, hardness, and roughness of specimens manufactured through both additive and conventional production routes. The study's findings show that it is feasible to attain analogous surface quality when proper finishing is applied to L-PBF samples. Although, despite the comparable surface quality, the contact fatigue performance was significative lower on the AM sample when compared to the conventionally manufactured. Additionally, additive manufacturing brings up new challenges to performance by presenting a heterogeneous stress distribution and sub-superficial porosity. In conclusion, to attain a desirable surface integrity for additive manufactured parts, further research should not only focus on improving the process parametrization but should also developing finishing routes especially oriented to additive manufacturing, considering therefore how the interaction between the manufacturing processes will evolve into a desirable surface integrity state. [ABSTRACT FROM AUTHOR]

Additive manufacturing processes for the production of large structural components, such as wire arc additive manufacturing (WAAM), offer great manufacturing potential due to their flexibility and design freedom, e.g. for the automotive industry. In order to achieve the desired surface and properties of the surface zone, additive manufacturing is usually followed by mechanical finishing. In this paper, the influence of the process parameters during WAAM and deep rolling (DR) on the residual stresses and the lifetime of AlSi12 components is investigated. Knowledge of the interactions between the process parameters in WAAM and DR as well as their effect on the surface zone properties and the application behavior is elementary. This enables the prediction of the component properties and quality. With the help of the appropriate selection of the process parameters, the residual stress state and the service life can be increased in such a way that components with high fatigue strength can be manufactured. This results in an average increase in service life of up to 17.8 times. [ABSTRACT FROM AUTHOR]

Due to the large design freedom of additive manufacturing (AM), components manufactured by laser powder bed fusion (PBF-LB) possess a high lightweight potential, which increases the importance of PBF-LB for applications in the automotive, aviation and aerospace industries. The typically high surface roughness of PBF-LB parts leads to a significant reduction in fatigue strength. Therefore, a finishing process for improving the surface roughness of complex PBF-LB parts is required. Stream finishing represents such a process. In a first step, surface roughness evolution and abrasion rates were measured for specimens manufactured with PBF-LB at different stages of the finishing process. In a second step, fatigue specimens were manufactured, machined both by turning and stream finishing, and tested by rotating bending fatigue tests. To evaluate crack initiation and propagation, the fracture surfaces were examined by scanning electron microscopy. The microstructure and microhardness near the surface were investigated to assess the influence of the surface layer on the fatigue behaviour. Stream finishing proved to be a suitable finishing process, as the specimens exhibited very low surface roughness and improved fatigue behaviour compared to turned specimens, especially for lower stresses. [ABSTRACT FROM AUTHOR]

Additively manufactured workpieces often exhibit issues such as porosity, roughness, and induced tensile residual stresses. The surface characteristics of such workpieces can be modified by post-processing techniques like Machine Hammer Peening (MHP). However, the influence of MHP on surface characteristics of additively manufactured workpieces has not been comprehensively studied. Thus, this study investigates the influence of MHP on surface integrity of workpieces created using wire-based Laser Metal Deposition (LMD-w) with Inconel 718 wire. The effect of secondary temperature on surface integrity is first evaluated. Following this, the impact of MHP process parameters on surface integrity is systematically investigated. The quantification of surface integrity is achieved by measuring its key aspects such as topography and surface layer characteristics, including surface roughness, waviness, hardness, recrystallization, and residual stresses. Microstructural analysis of the selected samples is conducted employing Scanning Electron Microscope (SEM) and optical microscopy. The obtained results provide valuable insights into the effectiveness of MHP on the surface integrity of LMD-w workpieces, along with practical guidelines for its optimization. Extending its impact, the study enhances the broader understanding of surface treatment in additive manufacturing. [ABSTRACT FROM AUTHOR]

The implementation of additive manufacturing as a disruptive process for the development of components has generated the need to know manufacturing parameters to obtain mechanical properties similar to or better than those of conventional processes. Thus, the improvement and optimisation of materials used have aroused interest in converting Polylactic acid (PLA) 3d printed parts from prototyping to functional components. In this regard, they must withstand cyclical loads. To do so, conventional methods must consider all variables used in the manufacturing process. Herein, we propose the use of neural networks to perform mechanical fatigue analysis of the printed components of PLA. The mechanical behaviour of the printed components was expressed for the neural network as parameters based on quasistatic tests, and the output of the network was the expected fatigue life in cycles. The initial quasistatic behaviour of the 3d printed parts was linearly elastic. However, a viscoelastic behaviour developed over time. The discharge time between charging cycles influenced the cumulative damage process. According to the experimental results and their correlations, the fatigue life of printed components can be predicted using neural networks by achieving an average error of 1.59% . [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) technology, such as selective laser melting (SLM), has been used to fabricate medical devices of Ti-6wt.% Al-4wt.%V (Ti6Al4V) alloys in dentistry. Strontium (Sr) has been shown to have the potential to treat osteoporosis. The aim of this study was to investigate the physicochemical and biological properties of strontium-containing coatings on selective laser melted Ti6Al4V (SLM-Ti6Al4V) substrate. The disk of Ti6Al4V was prepared by SLM method. The strontium-containing coatings were prepared by micro-arc oxidation (MAO) in aqueous electrolytes. The surface topography, chemical composition, and phase of strontium-containing MAO (SrMAO) coatings were performed by scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS), and thin film X-ray diffraction (TF-XRD), respectively. The apatite-forming ability of the MAO coatings was conducted in simulating body fluid (SBF), and the cell proliferation was determined by methylthiazoletetrazolium (MTT) assay. The microstructure of SLM-Ti6Al4V displays acicular α-phase organization. The TF-XRD results indicated that the phase of SrMAO coating was anatase, rutile, and titanium. The calcium, phosphorus, and strontium were detected in the coatings by EDS. Using the SEM, the surface morphology of SrMAO coatings exhibited a uniform 3D porous structure. The SrMAO coatings could induce a bone-like apatite layer after immersion in SBF, and presented significantly higher cell proliferation than untreated specimens in in-vitro experiments. All findings in this study indicate that SrMAO coatings formed on SLM-Ti6Al4V surfaces exhibit a benefit on biological responses and thereby are suitable for biomedical applications. [ABSTRACT FROM AUTHOR]

Ultrasonic impact treatment (UIT) could improve the residual stress of additive manufactured parts. However, there is almost no report on the effect of in-situ UIT, where the UIT equipment moves with laser metal deposition (LMD) equipment at a controllable offset, on residual stress. In this work, the effect of in-situ UIT on residual stress and the effect of offset on the effectiveness of in-situ UIT were investigated by finite element analysis. The stress change introduced by in-situ UIT includes the impact and cooling process. The results show that the value of residual compressive stress (RCS) introduced by the impact of in-situ UIT is higher than that after ex-situ UIT. In the cooling process, the unfinished shrinking behavior reduces it. The increasing offset has little influence on the residual stress field introduced by the impact of in-situ UIT. Residual compressive stress (RTS) reappears in the deposition layer after the cooling process of in-situ UIT, when the offset is small, increasing the offset can retain the RCS. In-situ UIT can improve the residual stress field and the impact of in-situ UIT becomes increasingly similar to that of ex-situ UIT as the offset increases. The findings serve as invaluable guidance in devising strategies to manage and mitigate residual stress in components produced by LMD and other additive manufacturing techniques. [ABSTRACT FROM AUTHOR]

This in vitro study aimed to evaluate the additive manufacturing (AM) of cobalt chromium Co-Cr and titanium Ti alloy clasps for clinical use. After scanning the Ni-Cr die of the first molar, Akers' clasps were designed using computer-aided design/ computer-aided manufacturing (CAD/CAM). The clasps were manufactured from Co-Cr-W dental alloy and Ti-6Al-4V alloy powder using AM machines. Then, they were divided into two groups. The initial retentive force of the clasps was measured using a universal testing machine. Cyclic loading of the clasps was carried out by a specially designed insertion-removal testing apparatus in wet condition up to 5000 cycles. Retentive force was measured at 1000, 2000, 3000, 4000, and 5000 cycles. Moreover, the intaglio surface of each clasp was scanned using the scanner; and superimposition between the pre- and post-cycling clasp files was performed to evaluate deformation after cyclic loading. The fitting surfaces of retentive clasp tips were examined with a scanning electron microscope (SEM). Finally, it has been found that the initial retentive force for the Co-Cr group was 10.81 ± 0.37 N, and for the Ti group was 5.41 ± 0.18 N. Additionally, during the testing periods, both Co-Cr and Ti clasps continued to lose retentive force within the cycles of placement and removal. This effect was more prominent in the Co-Cr than in the Ti clasps. The distances between pre- and post-cycling in the retentive arm were −0.290 ± 0.11 mm and −0.004 ± 0.01 mm in Co-Cr and Ti alloys, respectively, and in the reciprocal arm were −0.072 ± 0.04 mm and −0.032 ± 0.04 mm in Co-Cr and Ti alloys, respectively. The retentive force required to remove the Ti clasps was found to be significantly lower than those required to dislodge the Co-Cr clasps. Co-Cr and Ti clasps lost significant amounts of retentive force from the initial use to the 3.5-year periods of simulated clinical use. [ABSTRACT FROM AUTHOR]