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Wire-arc additive manufacturing, droplet oscillation momentum, control strategy, molten pool fluctuation, surface-forming quality, Science, Manufactures, and TS1-2301

ABSTRACTIn feedback control systems of wire-arc additive manufacturing (WAAM), timely adjustments before the occurrence of deviations (feedforward control) would reduce excessive requirements on the sensitivity and accuracy of characteristic parameters of control systems. However, the search for characteristic parameters suitable for feedforward control is extremely rare in the WAAM field. Herein, based on ‘mass-spring' theory, a model of droplet oscillation momentum (DOM) is developed to describe the dynamic behavior of a pendant droplet and its influencing mechanism on surface roughness. The model combines the contribution of wire movement to droplet displacement with experimental correction of the spring/damping coefficients. The results show that the predictions of the model are in good agreement with the experimental values, and DOM is quadratically correlated with the surface roughness. Therefore, the model can be expected as a characteristic parameter to elucidate the development of surface-forming quality of WAAM-fabricated components.

Food 3D printing, Mechanical properties, Post-processing, Porosity topology, Science, Manufactures, and TS1-2301

ABSTRACTThe study of the mechanical properties of 3D printed food is crucial for food personalisation. Texture impacts the sensory experience along the oral food consumption. This work aimed to investigate the mechanical properties of post-processed printed food samples with different porosity topologies (triangled-shape/squared-shape). Image analysis showed changes in the structure before and after post-processing. The mechanical properties characterised via 3-point bending tests revealed that triangle-shaped topologies presented lower strength (20% less) and higher flexural stiffness (≈20%) when compared to the square-shaped topologies. A qualitative comparison of the porosity topologies and their role in the stiffness of structures under tensile and bending loads was performed via finite element models. The flexural stiffness varied between the triangle-shaped designs (13–35%) but remained almost constant for square-shaped designs (40–43%). The results presented in this work showed that the mechanical properties of 3D-printed food could be modified by the selection of porosity topology.

Laser sintering, analytical modelling, degradation, additive manufacturing, polymer material, Science, Manufactures, and TS1-2301

ABSTRACTThe optimisation of selective laser sintering (SLS) of polymeric materials, based on analytical equations providing fast predictions, can broaden the SLS application area. However, the selection of SLS polymeric materials is currently rather limited, due to specific requirements regarding sufficient flowability and limited molecular degradation. The present work highlights that upgrading existing analytical equations, by incorporating a well-calculated overlay factor and correcting for pre-heating starting at ambient conditions, can accelerate SLS screening. Model validation is performed based on density, colorimetric, morphological and mechanical analysis of printed parts, focusing on the prediction of the laser power which corresponds to the onset of degradation, taking polyamide powder as a reference case. Furthermore, the optimised model is successfully applied for two other polymer powders, namely thermoplastic co-polyester and thermoplastic polyurethane powder, to highlight a better overall description of the SLS degradation mechanism.

Continuous fibre, Broadband absorption, Metamaterials, 3D Printing, Science, Manufactures, and TS1-2301

ABSTRACTElectromagnetic pollution and military stealth technique have raised tremendous interest in high-performance microwave-absorbing structures. However, an ultra-broadband absorbing functional structure is still in urgent demand. Herein, a novel continuous conductive fibre-based absorbing metamaterial was successfully designed and fabricated by multi-materials hybrid 3D printing technique. Benefitting from the highly symmetric structured design of a super unit cell and appropriate conductive property of continuous fibre, the absorbing metamaterial is demonstrated to have an ultra-wide band microwave absorption and polarisation insensitivity. Furthermore, the thickness of the proposed metamaterial is only 3.2 mm of 0.085λmax. In the wave absorption test, the metamaterial shows a broadband absorption of 8–18.1 GHz (greater than 90%) and maintains a good absorption effect at an incident angle of 40°. The design and fabrication method of the continuous fibre-absorbing metamaterial provides a new idea for the realisation of the integrated bearing and absorbing metamaterial, which will greatly promote the practical application of absorbing metamaterial.

Additive manufacturing, PLA, ZnO, nanocomposite, fused filament fabrication, fused deposition modelling, Science, Manufactures, and TS1-2301

ABSTRACTPoly(lactic acid)-zinc oxide (PLA-ZnO) nanocomposites for fused filament fabrication have potential applications in the biomedical field as they combine the bio-compatibility of PLA with the antibacterial properties of ZnO. This work investigates the effects of masterbatch mixing strategy, ZnO concentration and ZnO surface treatment (silanisation) on the printability and the mechanical performance of the nanocomposites as a pre-requirement to the wider uptake of these materials. The results showed that the printability decreased as the filler loading increased. However, the surface treatment of the ZnO powder enhanced the matrix-filler interfacial interactions and reduced the thermal degradation of PLA. This ameliorated the printability and the tensile properties of the nanocomposites filled with up to 5 wt.% of ZnO. Moreover, despite the additional thermal treatment, melt-mixing prevented the degradative effect induced by the solvent used for solvent mixing. Future work will focus on assessing the antibacterial properties of the nanocomposite FFF parts.

Additive manufacturing, laser powder bed fusion, polyaryletherketone, nanocomposite, graphene, Science, Manufactures, and TS1-2301

ABSTRACTAchieving good dispersion of graphene (GNP), in polyetheretherketone (PEEK), is challenging due to the high melt viscosity, solvent resistance and processing temperature of PEEK. In addition, certain manufacturing processes tend to enhance the anisotropy due to GNP orientation within the structure. This study investigated the fabrication of nanocomposite parts through hot compression moulding (C-MOULD) and powder bed fusion (PBF) processes, using powder with GNPs fused to the surface of polymeric particles, through a process called mechanofusion. The method applies mechanical forces of compression, shear and impact to generate a mechanical bond between materials, in this case, O2 functionalised GNP and a developmental polyaryletherketones (PAEK) grade powder. The novelty of this work is in the combination of processes used for manufacturing (material preparation and actual manufacturing processes), which are scalable and efficient in comparison with existing methods (such as solvent mixing or melt-compounding). The mechanofusion GNP-PAEK composite powders were successfully printed for the first time using the EOS P800 system with notable improvements in electrical and mechanical properties. This study highlights that the mechanofusion process could be used as an efficient process for making multifunctional nanocomposite materials and this can be combined with additive manufacturing (AM) processes to produce complex components.

Direct wire writing (DWW), flexible electronics, conductive lines, sensor, Science, Manufactures, and TS1-2301

ABSTRACTThis work proposes a rapid manufacturing technique for the conductive lines applied in flexible electronics, which is referred to as the ‘direct wire writing (DWW)’ technique. The fine metal wire is dragged out of the needle by adhesion, and attached to the stick-on substrate synchronously along design paths to form high-quality circuits. This technique overcomes the unstable performance of ink-based conductive lines fabricated by screen printing, spraying, 3D printing, etc., and avoids complex processes for stable metallic circuits mainly manufactured by the photolithography method, etc. Firstly, the forming mechanism of dominating the micro deformation behaviour (local-debonding, slip, warping) is clarified and analysed, which provides guidelines for fabricating in-plane wire patterns and 3D structural circuits rapidly and easily. Subsequently, some practical applications, including strain rosette, wearable sensor patch and light display are presented, showing the promising potential of the DWW technique in the ongoing exploration of flexible electronics.

Ti 6Al–4V alloy, Zirconia, Co–Cr–Mo alloy additive manufacturing, Osteoarthritis, Knee joint, FDM, Internal medicine, RC31-1245, Surgery, and RD1-811

Additive manufacturing (Rapid Prototyping) is a significant innovation in medical field. It allows scientists to create custom-made parts that are often more precise and robust than their standard counterparts. Osteoarthritis (OA) is very common and serious problems in aging people. It is a progressive disease that affects the cartilage, the substance that cushions the bones and joints. Artificial knee joints are being developed as a sort of replacement for the human knee joint. One of the most intricate parts of the human body is the knee joint. This complex joint comprises of a ball-and-socket relationship, which is a very difficult part of the anatomy to design. The joint consists of both the kneecap and the Cartilage, and it has been designed with the intention of having the joint supported by a bone, rather than a cartilage. In this review article the results of a recent study, which was performed by researchers from the various renowned universities of Europe & United States of America over Artificial Knee Joint by Additive Manufacturing Technology.

Post-consumer recycling, Circular economy, Metalized film, Thermal properties, Mechanical properties, Renewable energy sources, TJ807-830, Environmental engineering, and TA170-171

In the recycling point of view, the metalized plastic film is widely known to be one of the most difficult materials to be recycled due to its structural complexity. This paper investigates the effects of the ground metalized-plastic film (MF) as a filler and reinforcement in recycled polypropylene (rPP) packaging to produce a new material through circular economy. MF was incorporated to rPP from 2 to 10 wt% and it was processed by using a twin-screw extruder and an injection molding machine. For MF, elemental analysis, and x-ray diffractometer (XRD) confirmed the existence of C, O, and Al, while the differential scanning calorimetry (DSC) result evidenced the melting position of linear-low density polyethylene (LLDPE). For, rPP/MF composites, MF was found to significantly reinforce rPP with the increased tensile strength. A maximum increase of the tensile strength by around 33% was observed when MF was added at 8 wt%. Elongation at break was found to reduce with MF loading. However, there was no significant difference among rPP with 6–10 wt% MF. DSC results indicated the shifts of both crystallization and melting peaks together with the reduction of the degree of crystallinity (Xc). Based on the tensile strength, tensile elongation at break results together with the statistical analysis and waste utilization issues, the rPP with 10 wt% MF formulation was selected as a final product prototyping.

rapid prototyping, automated hardware design, corner detection codesign, MBD, HDL coder, Xilinx Zynq-7000, Engineering (General). Civil engineering (General), TA1-2040, Technology (General), T1-995, Information technology, and T58.5-58.64

Computer vision systems use corner detection to identify features in an image. In applications such as motion detection, tracking, picture registration, and object recognition, corner detection is often one of the initial steps. In this paper, a real-time image processing system based on Harris corner detection was designed and implemented using Zynq architecture and model-based design tools. The system was based on a development board containing the Zynq-7000 chip, which consists of a combination of FPGA and microprocessor, and the image taken with a high-resolution camera was processed in real-time by applying color conversion and Harris corner detection. The filter hardware designs used in the system were made using the HDL Coder tool in Matlab/Simulink without writing HDL code. The hardware that receives images from the camera was designed on a model-based basis with the Xilinx Vivado 2020. The HDL code that was implemented on the Xilinx ZedBoard using Vivado software was then validated to ensure real-time operation with the incoming video stream. The results achieved exhibited superiority compared to prior implementations in terms of area efficiency (reduced number of gates on the target FPGA) and speed performance on an identical target card. Using the rapid prototyping approach, two alternative hardware accelerator designs were created using various high-level synthesis tools. This design used less than 50% of the host FPGA's logic resources and was at least 30% faster than current implementations.

quantum computing, quantum computing techniques, Telecommunication, and TK5101-6720

Abstract In recent years, numerous research advancements have extended the limit of classical simulation of quantum algorithms. Although, most of the state‐of‐the‐art classical simulators are only limited to binary quantum systems, which restrict the classical simulation of higher‐dimensional quantum computing systems. Through recent developments in higher‐dimensional quantum computing systems, it is realised that implementing qudits improves the overall performance of a quantum algorithm by increasing memory space and reducing the asymptotic complexity of a quantum circuit. Hence, in this article, QuDiet, a state‐of‐the‐art user‐friendly python‐based higher‐dimensional quantum computing simulator is introduced. QuDiet offers multi‐valued logic operations by utilising generalised quantum gates with an abstraction so that any naive user can simulate qudit systems with ease as compared to the existing ones. Various benchmark quantum circuits is simulated in QuDiet and show the considerable speedup in simulation time as compared to the other simulators without loss in precision. Finally, QuDiet provides a full qubit‐qudit hybrid quantum simulator package with quantum circuit templates of well‐known quantum algorithms for fast prototyping and simulation. Comprehensive simulation up to 20 qutrits circuit on depth 80 on QuDiet was successfully achieved. The complete code and packages of QuDiet is available at https://github.com/LegacYFTw/QuDiet.

Digital mental health, Human-centered design, Methodology, Information technology, T58.5-58.64, Psychology, and BF1-990

As digital mental health interventions (DMHIs) proliferate, there is a growing need to understand the complexities of moving these tools from concept and design to service-ready products. We highlight five case studies from a center that specializes in the design and evaluation of digital mental health interventions to illustrate pragmatic approaches to the development of digital mental health interventions, and to make transparent some of the key decision points researchers encounter along the design-to-product pipeline. Case studies cover different key points in the design process and focus on partnership building, understanding the problem or opportunity, prototyping the product or service, and testing the product or service. We illustrate lessons learned and offer a series of questions researchers can use to navigate key decision points in the digital mental health intervention (DMHI) development process.

Technology, Engineering (General). Civil engineering (General), TA1-2040, Applied optics. Photonics, and TA1501-1820

Large-scale pretrained language models have been a revolution in human-machine communication. Recently, such language models also generate code for required tasks. The objective of this work is to evaluate the functionality of the codes generated by ChatGPT (version 15-Dec-2022) for point cloud processing. The programming language selected for the test was MATLAB due to the extensive use in prototyping and toolboxes for Computer Vision and LiDAR. Using the Question-Answer system, the ChatGPT was asked for codes to calculate surface normals, curvature, eigenvalues, and eigenfeatures, with specific parameters and outputs. The provided codes were compiled and executed. The results show that ChatGPT can generate functional code for very specific and short applications, however, it is not capable of generating large code involving the correct use of loops, indexes, or equations.

Nanocellulose, Alginate, Hydrogel, Films, 3D printing, Architectural design, Materials of engineering and construction. Mechanics of materials, and TA401-492

Cellulose nanofibril hydrogel mixed with an aqueous solution of sodium alginate is a novel bio-based material suitable for 3D printing of lightweight membranes with exquisite properties and sustainable traits. However, fundamental knowledge enabling its applications in architectural design is still missing. Hence, this study examines the macro-scale features of lightweight membranes from cellulose nanofibril-alginate hydrogel, relevant for the design of various interior architectural products, such as wall claddings, ceiling tiles, room partitions, tapestries, and window screens. Through iterative prototyping experiments involving robotic 3D printing of lightweight membranes, their upscaling potential is demonstrated. Correlations between toolpath designs and shrinkages are also characterized, alongside an in-depth analysis of coloration changes upon ambient drying. Further, the tunability potential of various architectural features, enabled by bespoke 3D printing toolpath design, is discussed and exemplified. The aim is to expose the wide palette of design possibilities for cellulose nanofibril-alginate membranes, encompassing variations in curvature, porosity, translucency, texture, patterning, pliability, and feature sizes. The results comprise an important knowledge foundation for the design and manufacturing of custom lightweight architectural products from cellulose nanofibril-alginate hydrogel. These products could be applied in a variety of new bio-based, sustainable interior building systems, replacing environmentally harmful, fossil-based solutions.

Hole flanging, Incremental sheet forming, Hardness, Artifiical neural network (ANN), Forming limit diagram (FLD), Numerical simulation, and Technology

In the single point incremental hole flanging (SPIHF) process, a sheet material with pre-cut holes is deformed using the SPIF technique to generate a flange, making it an effective approach for low volume manufacturing and quick prototyping. In the case of the SPIHF technique, the post-forming hardness property, the forming limit diagram (FLD), and spring-back phenomena are not completely evaluated. To this end, this paper employs experimental investigation and numerical validation to analyse the impact of SPIHF process parameters like tool diameter, feed rate, spindle speed, and initial hole diameter on these aspects for the truncated incrementally formed components made from AA1060 aluminium alloy and DC01 carbon steel. The plasticity behaviour of both sheet metals was simulated using the Workbench LS-DYNA model and ANSYS software version 18. Additionally, Cowper Symonds power-law hardening was added to the model to account for material properties. The average post-hardness of AA1060 and DC01 was evaluated using an SPIHF prediction model based on the performance of an artificial neural network (ANN). This ANN model was developed using a feed-forward back-propagation network trained using the Levenberg-Marquardt approach. The ANNs 4-n-1 were created by varying the transfer functions and the number of hidden neurons. Greater spindle speed and bigger pre-cut holes were shown to significantly increase the post-formed hardness of the truncated components, whereas the converse was seen when using a higher feed rate and a larger tool diameter. In addition, the FLD and spring-back improved dramatically with larger hole diameters. Employing correlation coefficient (R) and mean square error (MSE) as validation measures, it was shown that the established ANN models accurately predicted the SPIHF process response. Both the DC01 and AA1060 neural network models with a 4-8-1 network architecture performed very well, with MSE and R values of 0.0000105 and 1 for DC01 and 0.02613 and 0.99982 for AA1061.

Biomedical imaging, 3D printing, prototyping, material science, polymer characterization, Materials of engineering and construction. Mechanics of materials, TA401-492, Biotechnology, and TP248.13-248.65

ABSTRACTIn biomedical imaging, it is desirable that custom-made accessories for restraint, anesthesia, and monitoring can be easily cleaned and not interfere with the imaging quality or analyses. With the rise of 3D printing as a form of rapid prototyping or manufacturing for imaging tools and accessories, it is important to understand which printable materials are durable and not likely to interfere with imaging applications. Here, 15 3D printable materials were evaluated for radiodensity, optical properties, simulated wear, and capacity for repeated cleaning and disinfection. Materials that were durable, easily cleaned, and not expected to interfere with CT, PET, or optical imaging applications were identified.

3d food printing, extrusion, food waste, sustainability, dysphagia, hydrocolloids, Science, Manufactures, and TS1-2301

Food waste utilisation and zero waste approach are among the many ways of building a sustainable economy. Food waste as authentic edible food being accepted by the consumers still has many barriers to overcome. One tool to help in the valorisation of food waste to value-added products is three-dimensional food printing (3DFP). These products can lead to easier and greater acceptance of food waste by consumers, having familiar nature with respect to taste, texture and appearance as other consumables. In the present study, food ink recipes were formulated from spinach stems and kale stalks, the common green leafy vegetable wastes. These spinach and kale inks were then characterised on their rheological properties of shear thinning and yield stress. The inks were subjected to IDDSI tests meant for standardisation of soft foods for dysphagia patients. This paper demonstrates ways of converting vegetable wastes into edible diets that are aesthetically pleasing through 3DFP.

Multiple materials, additive manufacturing, wire arc additive manufacturing, Science, Manufactures, and TS1-2301

ABSTRACTThe dynamic landscape of additive manufacturing (AM) is undergoing a transformative phase with the advent of multiple wire arc AM (MWAAM) processes. This systematic review offers an exhaustive exploration of the latest advancements and multifaceted applications of these innovative techniques within the realms of AM and welding. Prominently discussed processes encompass Bi-Metallic Wire Arc Additive Manufacturing, Twin Wire Arc Additive Manufacturing, Tandem Gas Metal Arc Welding, Twin-Wire Plasma Arc Additive, and Hybrid Wire Arc Additive Manufacturing. These techniques, instrumental in fabricating an array of materials from titanium aluminides to low-carbon steel, underscore the versatility and potential of modern AM. The application breadth spans key industries such as aerospace, naval, automotive, and energy, highlighting the ubiquity and relevance of these processes. While they promise enhanced productivity, improved material attributes, and economic efficiencies, challenges persist, including the need for meticulous parameter control, an in-depth grasp of foundational physics, and the development of sophisticated predictive models. Projecting into the future of AM, this review anticipates a harmonised integration of computational advancements with automation, positioning these MWAAM processes as pivotal in the next wave of manufacturing innovations.

additive manufacturing, 3d printing, field assistance, magnetic field assistance, electric field assistance, acoustic field assistance, additive manufacturing of polymers, additive manufacturing of metals, Science, Manufactures, and TS1-2301

Additive manufacturing (AM) has emerged as a transformative technology capable of fabricating complex geometries and multi-material structures across various industries. Despite its potential, challenges persist in terms of limited material selection, anisotropic properties, and achieving functional microstructures in polymer and metal composites. Field-assisted additive manufacturing (FAAM) employs external fields like acoustic, magnetic, and electric fields. It has shown promise in addressing these limitations by controlling filler orientation and concentration in polymeric composites and improving surface finish and microstructure in metals. This review paper provides a comprehensive analysis of the state-of-the-art FAAM processes for polymer and metal composites, focusing on material compatibility, the mechanics of each field, and their integration with AM technologies as well as current applications, limitations, and potential future directions in the development of FAAM processes. Enhancing FAAM process understanding can create tailored anisotropic composites, enabling innovative applications in aerospace, automotive, biomedical fields, and beyond.

3d printing, additive manufacturing, cooperative robots, mobile robots, teams of robots, cooperative printing, Science, Manufactures, and TS1-2301

Additive manufacturing (AM) is a key enabler and technological pillar of the fourth industrial revolution (Industry 4.0) as it increases productivity and improves resource efficiency. However, current AM systems present some limitations in terms of fabrication time, versatility, and efficiency. The concept of teams of robots represents a novel approach for AM aiming to address these limitations. This review paper discusses the current state-of-the-art of the use of cooperative AM systems based on gantry systems, robotic arms, and mobile robots. The information flow, path planning and slicing strategies are discussed in detail, and several examples of the use of cooperative AM systems are provided. Finally, major research challenges and future perspectives are discussed.