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The uniaxial compression experiments were conducted on GCr15 bearing steel to obtain the flow stress curves under hot deformation conditions. Based on the results of uniaxial compression experiments, finite element modeling was conducted on the cross wedge rolling (CWR) of GCr15 bearing steel balls, and numerical simulation was conducted using Simufact Forming 16.0. The results show that the distribution of effective strain of existing CWR steel balls is uneven, which may lead to uneven quality of steel balls. In addition, the three principal stresses at the center of the steel balls are all tensile stresses, and the effective stress at the center of the middle ball is relatively large, which can easily induce central defects. Moreover, different diameter billets were used for steel balls rolling experiments. It can be seen that when the die cavity is underfilled with billet, the rolled steel balls have no central defects. When the die cavity is fulfilled with billet, there is central piercing appearing at the middle ball, while the side balls have no obvious central defects. Finally, the paper proposes the method of even numbered ball rolling (ENBR) which starts from the middle connector to improve the CWR process of steel balls.

This paper outlines the creation and evaluation of Benchtop-AFP, an innovative approach to producing composite materials akin to Automated Fibre Placement (AFP) but without the high capital expenses typical of traditional AFP methods. This unique technique, with further refinement, could serve as a valuable tool for research and development in automated fibre placement. As a world first, it aims to democratise AFP research, particularly for institutions where access to full-scale AFP facilities is unavailable and limited due to financial, skills, or safety constraints. This article presents the new method and provides examples of samples generated using this technique.

Lubricant breakdown and galling phenomena are widely observed at the tooling surface during the stamping of aluminium components for the automotive industry, which compromise the formed surface quality and reduce tool-life. The lubricant performance has been found to be significantly influenced by its method of application. In the present research, a dedicated lubricant was evaluated by utilizing an advanced lab-scale friction testing system, TriboMate, and the effects of lubricant application method and lubricant quantity on the coefficient of friction evolution were investigated. It has been found that lubricant performance was significantly improved when the lubricant was applied on the hot workpiece blank, compared to the cold tooling surface, and when the lubricant quantity was increased. The gradual increase of friction evolution despite lubricant application on the workpiece blank was found to be due to the formation of an aluminium transfer layer at the tooling surface.

Manufacturing significantly contributes to global warming due to its substantial carbon emissions. United Nations sustainable development goals support the reduction of carbon emissions in the manufacturing sector, which can be accomplished by making the manufacturing process sustainable with a minimal carbon footprint. This is also appropriate for novel manufacturing processes such as additive manufacturing. This study introduces the investigation of the additively manufactured specimen. Prior research delves into examining the impact on the energy consumption of solid specimens under distinct printing process parameters. Nonetheless, the influence of electrical energy consumption and total carbon footprint for the additively manufactured solid and lattice structure has yet to be investigated. The current study fills the research gap by assessing layer thickness and infill density on both specimens’ electrical energy consumption and total carbon footprint. The presented study offers insight into the impact of layer thickness and infill density for the solid and lattice structure specimens and their comparison of electrical energy consumption and total carbon footprints. The results demonstrated that a rise in an infill density directly correlates with increased energy consumption and carbon footprints. However, rising layer thickness resulted in a reduction in both power consumption and carbon footprints. Furthermore, it was observed that the triangular, octagonal, and hexagonal cellular structures manifest higher power consumption when the infill density is set at 50% and 80%, respectively. Moreover, when assessing a solid specimen at 100% infill density, the total carbon footprint exhibits increases of 12%, 21%, 23%, and 41% in comparison to triangular, octagonal, hexagonal, and square lattice structures, respectively.

This paper revisits double-flush riveting to compare the static and fatigue performance of the resulting joints with those fabricated by conventional bolting. Experimental measurements of electrical resistance, combined with finite element analysis of electric current flow, serve a dual structural and electrical purpose of validating the number of cycles after which the loss of contact between the overlapping sheets becomes significant, and evaluating the relative performance of both types of joints in electric energy distribution systems built upon aluminum strips. The first of these purposes is a novelty in fatigue testing while the second paves the way for improving the efficiency of electric power grids.

In this study, two types of Cu/Nb multilayer composite sheets with individual layer thicknesses of 11.11 μm and 0.35 μm, respectively, were first prepared and then tested by micro-blanking. The results show that the sheets of 0.35 μm exhibit higher ultimate tensile and shear strengths, and greater elongation, compared to those with an individual layer thickness of 11.11 μm. The sheet with an individual layer thickness of 11.11 μm achieves optimal blanking accuracy at a relative blanking clearance of 7%. Additionally, when the relative blanking clearance is 3%, it exhibits a significant proportion of smooth areas on the shear surface. Investigation of the shear surface at different ratios of punch stroke to sheet thickness (h/t) reveals that the Cu/Nb multilayer composite sheet experiences significant extrusion and bending during the micro-blanking process. Furthermore, the laminated structure exhibits remarkable continuity and deformation mobility, delaying crack formation. This study provides theoretical support for the plastic micro-blanking technology of multilayer composite.

It is difficult for as-cast titanium alloys to achieve high strength and toughness due to the presence of coarse β grains. In this study, multi-directional forging (MDF) was employed to break down the coarse β grains into fine grains and the mechanism of strengthening and toughening was also revealed. Results indicated that nearly all peaks corresponded to the β phase, with the α phase peaks being almost imperceptible. As the MDF temperature increased, the grain size initially decreased and then increased. All the dislocation is concentrated near the grain boundaries. The refinement of the grains can be attributed to the combined effects of mechanical crushing refinement and dynamic recrystallization. The tensile strength and fracture toughness is 1130 MPa and 82 MPa·m1/2. Grain refinement and dislocation proliferation caused by MDF are the main contributors to the improvement of strength and toughness in the alloys. This discovery lays a solid foundation for further research on new ultra-high strength and toughness titanium alloys, while also providing a new design concept for other high-performance alloys.

In present work, Fields Activated Sintering Technology (FAST), has been applied to successfully sinter the high-entropy alloy (HEA) samples. Based on the analysis of the microstructure, relative density and microhardness of the sintered HEA samples, the influence of sintering temperature and pulsed magnetic field treatment (PMT) has been investigated. In terms of performance, HEA samples fabricated using PMT-powder sintering exhibit superior properties compared to UT-powders. Regarding elemental distribution, pre-treating the powders with a pulsed magnetic field can enhance the uniformity of the alloyed powder components. Furthermore, elevated sintering temperatures have been observed to substantially accelerate the densification process, thereby improving the relative density of the sintered samples.

Titanium matrix composite parts with excellent mechanical properties can be obtained by laser powder bed fusion (LPBF) by introducing nano SiC ceramic particles into titanium and titanium alloys. In order to cope with the instability of the forming quality of the parts caused by the addition of SiC particles, this paper proposes to explore the quality of single-track melt under different process parameters, to optimize the parameters more accurately to achieve better forming quality. In this paper, the influence of process parameters on the morphology and geometric size of the molten pool is studied, and the optimal molten track morphology parameters are selected for printing experiments. The results show that when the thickness of the powder layer = 30um is the optimal process parameter with the laser power 170 W, the scanning speed 1100 mm/s and the line energy density 0.155 J/mm. At this time, the molten track of TC11/SiC formed by LPBF process is continuous and stable, with good surface morphology.

The forming limit curve (FLC) has been commonly used tool to predict the metal forming cracking in engineering. Whereas, based on the assumption of plane stress state, the formability prediction of thick sheet of hot-rolled high-strength steels is quite different from the experimental measurement. Finite element simulation was used to study the effect of sheet thickness. It is found that extra stress along thickness is introduced between inside and outside the instability region, which become larger increased. Additionally, the visco-plastic self-consistent (VPSC) model and the M-K model are combined to establish the VPSC-MK model for investigating the influence of thickness difference. With reasonable capture of thickness stress, accurate prediction of FLC under different sheet thickness of hot rolled high-strength steel (HR-HSS) is well realized via VPSC-MK model. That is, it is revealed that the sheet thickness effect for HR-HSS mainly origins from normal stress induced during necking process.

The content of C element and in-situ Ti2AlC phase is adjusted to reduce the content of B2 phase in the TiAl matrix, ultimately improving the compressive properties of TiAl alloys. Results show that there is a high content of B2 phase inside the lamellar colony, and the Nb content in the B2 phase is higher than that dissolved in matrix. The addition of C element results in the formation of a round rod like reinforcing phase and refining the lamellar colony. As the C content increases from 0 to 3.0 at. %, the content of in-situ Ti2AlC reinforcing phase increases from 0 to 17.8 vol. %, the content of B2 phase decreases from 10.4 to 1.4 vol. %, and the size of the lamellar colony decreases from 161.3 to 19.5 μm. The decrease in the content of B2 phase is due to the preferential formation of Ti2AlC reinforcing phase in the liquid, Nb will preferentially dissolve in it, resulting in a more uniform distribution of Nb in the solidified structure and reducing the segregation of Nb. Then, Ti2AlC particles act as heterogeneous nucleation, increasing the nucleation sites in the alloy melt and refining the microstructure. According to the results of the compression test, as the C content increases from 0 to 2.5 at. %, the compressive strength increases from 1186.9 to 2154.5 MPa, and the compressive strain increases from 6.5 to 20.2 %. Therefore, the precipitation strengthening effect of Ti2AlC, the grain boundary strengthening effect of refined microstructure, and the decrease in the content of B2 phase jointly contribute to the improvement of the compressive properties at room temperature.

With one in four EU adults having disabilities and only half employed full-time, there is a need for enhanced workforce inclusion and accessibility. Despite Industry 4.0’s technological advancements, gaps in adoption persist for individuals with disabilities, hindering potential engagement within manufacturing. Leveraging Virtual Reality (VR)’s immersive qualities, empathic design principles were applied to empathise with individuals living with cognitive impairment in the context of digital manufacturing assembly processes. Exploring empathy’s role in enhancing inclusivity and accessibility, a qualitative study was conducted with manufacturing professionals and individuals with cognitive conditions, bridging the gap between current and future employees with diverse cognitive abilities. The findings, which are visualised through a novel user journey map, showcase VR’s potential as a tool for inclusive design by determining interaction modes that augment workforce diversity in manufacturing.

The Institute for Metal Forming Technology (IFU) at the University of Stuttgart / Germany since more than six years strongly strives to future oriented research work focusing on far-reaching concepts for digitization of metal forming processes. Main activities of engaged research groups are integrating sensors and actuators into metal forming machines or dies to analyse process data gained that way. Also, development of advanced methods for production data mining are related to those fields of activities. The paper therefore highlights strategies and practical applications of such digitization concepts. Also, important issues in terms of metal forming production processes will be addressed such as avoidance of scrap during ramp up phases and batch processing. Finally, the practical use of machine learning algorithms will be demonstrated in real trimming and metal forming processes.

This paper reports the study of the process chain for sheet metal forming using multi-point tooling for stamping at elevated temperatures and developing a complete production line integrating heating, intermediate fast-cooling, forming and aging. It aims to deliver a high-efficient and cost-effective sheet-metal forming technology with improved process capability and flexibility for the forming of high-strength sheet metal parts. Multi-point tooling sets are employed to test the flexibility of hot/warm-forming the lightweight high-strength metal sheets with fast tooling reconfigurability. The intermediate cooling with high cooling rates was achieved with a contact cooling system recently developed at the University of Strathclyde. With this pilot line, the aluminium sheets heated to the solution heat treatment (SHT) temperature were subjected to the intermediate cooling prior to forming with multi-point tooling. The cooling step is fast and controllable, with different cooling rates tested. The tests conducted on the pilot line demonstrated significant enhancement of the forming limit and manufacturing flexibility.

Pulsed magnetic field treatment, as a novel, quick and environmentally friendly post-processing approach can directly modify the coated tools without causing damage. This study examined the wear performance of the TiAlSiN-coated cemented carbide block specimens treated by the pulsed magnetic fields in both dry friction and cutting fluid friction. The findings show that TiAlSiN coating block specimens subjected to pulsed magnetic fields exhibit better wear resistance in both friction conditions. The wear rate of the coating decreases by 21.49% in a dry friction environment, and the friction process becomes more stable while the wear width of the coating decreases by 4.60% in the cutting fluid friction environment. In addition, the nano-indentation tests show that the hardness and elastic modulus of the coating increases by 6.58% and 5.64%, and the coating binding force increases by 15.27% after the treatment.

The construction industry is under pressure to address climate change and resource scarcity, leading to a growing interest in emerging biobased materials. This research focuses on microbial bricks through a life cycle assessment (LCA) based on ISO 14042 standards and CML2001 impact categories, examining various environmental criteria across a defined system boundary: Manufacturing. The findings highlight the positive potential of biobased materials in contributing to a greener supply chain management for the construction industry, even more than clay that we know as an earth (green) material. The biggest differences lay in the use of fossil fuels, electricity, transportation, and the assembly process. By addressing challenges and leveraging opportunities, these materials can lead to a more resilient and ecologically conscious sector, in alignment with the sustainable development goals (SDGs) defined by the United Nations (UN). The aim of this study is to stimulate additional dialogue and cooperation among academic and industrial participants to promote sustainable advancements in construction materials and manufacturing methods, transcending mere superficial green initiatives.

Titanium alloys pose significant challenges during machining, necessitates a thorough investigation into the impact of process parameters on machining Ti6Al4V alloy. This study investigates into the machinability of Ti6Al4V alloy under dry machining conditions using uncoated tools. The experimental design studiedthe effect of process parameters on the cutting power, surface roughness and material removal rate during dry machining of Ti6Al4V alloy. Utilizing Taguchi design of experiments, unified cutting experiments were conducted under dry conditions employing uncoated tools. The study findings revealed that optimal cutting parameters lead to improved cutting energy consumption, reduced tool wear, and enhanced surface finish and material rates. Analysis of Variance (ANOVA) and regression modelling were employed to obtain an objective function capable of predicting the best cutting conditions. ANOVA showed that cutting speed is the main factor for an increase in the cutting power with major contribution of 73 % whereas feed rate is the key factor for surface roughness with the contribution of 80 %. These results help to gain the advantages of dry machining under optimal conditions, facilitating clean production with minimal energy consumption and improved surface quality.

An experimental study is conducted to measure vibrations of the deforming sheet induced by tool rotations in a newly developed incremental sheet forming (ISF) process, Rotational Vibration assisted ISF (RV-ISF). Two new tool designs, elliptical double-offset tool and rosette tool of four-grooves, are tested in the experiment. Non-contact measurements by Eddy current sensor are obtained to characterise vibration frequency and amplitude of the deforming sheet during the RV-ISF of an aluminium alloy.

The damage behaviour of titanium alloy laser-welded seam during hot gas pressure forming was studied by experiment and simulation. The GTN damage model was used to simulate the hot gas pressure forming process of the welded blank. The evolution of the void volume fraction during the forming process was obtained. Hot gas pressure forming experiments of cup-shaped parts were carried out. The microstructure at different positions of the cup-shaped part was observed by scanning electron microscope. Results show that the damage to the weld seam during hot gas pressure forming was mainly related to the strain. The damage of the inside fillet near the flange develops most rapidly, and it easily cracks due to the large deformation during the free bulging stage. The damage on the bottom centre develops slowly at the free bulging stage. After the bottom of the cup-shaped part contacted the die, the volume fraction of damage on the bottom center continued to increase firstly and then reached to a stable value gradually. Various micro cracks were observed during the hot gas pressure forming. The volume fraction of cracks increased with the increasing strain, and the small cracks gradually grew, expanded, and merged to form larger cracks. It is important to control the maximum strain of the weld seam during the forming to avoid possible harmful damage.

A three-dimensional non-local crystal plasticity finite element model (CPFEM) integrating the evolution of geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) was developed to simulate the nano-indentation of single crystal copper. The simulation accurately reproduced published experimental results when considering force-depth curves, indentation size effect (ISE), anisotropic plastic deformation and sink-in phenomenon. The accumulated slip, i.e., shear strain in individual slip systems, was quantitively investigated. It is anticipated that the developed non-local CPFEM model can support future sub-micro and nanoscale manufacturing research as it enables the rapid exploration of slip system level mechanical response of a diverse range of crystalline alloys.

The complex shape microchannels is useful for the functional surface with capillary performance. The investigation of multi-pass micro-rolling was carried out using FE simulation and experiments. The effects of parameters, such as reduction of thickness, clearance between two rollers and downward displace of upper-roller, were studied by measure thickness of sheet and the depth of microchannels. It was found that the depth of microchannels increased with decreasing of clearance between two rollers. And, the shape of microchannels was changed from rectangle to complex shape in the second pass “without mould”. After process optimization of process, the multi-pass rolling can be used to fabricate microfeature with complex shape of sharp corner from the viewpoint of capillary performance.

An elliptical die hydraulic bulging test was carried out to explore the forming performance of 2A16 aluminum alloy sheets during hydroforming. By using five groups of elliptical dies with ovality of 1.0, 0.9, 0.8, 0.6, and 0.4, the effects of different pressure rates of 0.02 MPa/s, 0.04 MPa/s, and 0.08 MPa/s on the test results were studied, and different sheets thicknesses of 2 mm and 2.5 mm were also explored, then the equivalent stress and strain values obtained by theoretical calculation were also analyzed. Finally, the complete forming limit diagram (FLD) of the 2A16 aluminum alloy sheet at room temperature was plotted through the elliptical hydraulic bulging test and the uniaxial tensile test under the same test conditions. The results show that as the ellipticity increases, the maximum equivalent stress-strain value of sheets gradually increases; reducing the hydroforming pressure rate or increasing the thickness of the sheet can slightly increase the maximum bulging height of the sheet, but it has no significant impact on the maximum equivalent stress and strain value of this material. There is no noticeable difference in the FLD on the right side, indicating that its FLD is universal for a material.

Pre-strengthening hot/warm forming (PHF) technology can effectively shorten the microstructure evolution process of aluminium alloy deformation and heat treatment, and has a broad application prospect. In this paper, the process parameters in PHF are abstracted into sequence data, which is used as the input of long short-term memory neural network (LSTM) model to predict mechanical properties of aluminium alloy components after PHF process. Besides, the prediction models based on Random Forest (RF), Support Vector Regression (SVR) and Back Propagation Neural Network (BPNN) are established and compared with LSTM model. In addition, a Few-Shot Learning method based on the constitutive model is proposed to predict the properties of aluminium alloys.

Phase-measuring deflectometry (PMD) is a key measurement technology for specular surfaces form measurement. Compared with the phase measuring deflectometry techniques based on the conventional configuration, the near optical coaxial phase measuring deflectometry (NCPMD) can achieve compact configuration, light weight and insignificant measurement error caused by structure shadows by utilizing a plate beamsplitter. However, the introduction of the plate beamsplitter will make some influence of the measurement accuracy of the NCPMD system. In the one hand, the introduction of the plate beamsplitter can reduce the measurement accuracy of the NCPMD system due to the refractive of the ray between the two surfaces of the beamsplitter. In the other hand, due to the processing and manufacturing problems of the beamsplitter, there are inevitably certain unevenness errors on the upper and lower surfaces. In this paper, a virtual simulation system of NCPMD is established, and an error model of the NCPMD system by considering both the refraction influence and reflection influence of the plate beamsplitter is presented to analyse the shape reconstruction error caused by the plate beamsplitter.

Flexible manufacturing systems, such as Additive Manufacturing, Robotics and Computer Numerical Control (CNC) machines, can be readily deployed and operated in standard warehouse infrastructure providing the opportunity for the on-demand production of a wide variety of goods closer to their point of consumption. This has the potential to shift long-distance logistics towards raw material transport (which can be packed more tightly) and maximise the potential of zero-emission ‘last mile’ logistics. This paper reports a study to demonstrate the merits of Global Local (Glocal) supply chains in terms of the potential reductions in Greenhouse Gas Emissions (GHG). The study used the United Kingdom (UK) and its seven largest cities as the areas of supply and demand with material entering through Dover. The Monte-Carlo simulation showed that distributed production significantly outperforms single location manufacturing and product importing by up to 2-3x.

The stress relaxation with synchronous ageing of TA15 titanium alloy was studied under a plastic pre-loading condition. The evolutions of microstructure and room temperature properties were characterized. Results show that the stress can be eliminated by 85 %, and the ultimate tensile strength can be increased by 5 % compared to the as-received sheet at room temperature. The plastic pre-loading results in dislocation entanglements in primary α (αp) and precipitation of partial secondary α (αs). The main stress relaxation mechanisms in the early stage are the precipitation and growth of αs, stress-induced twinning and the dynamic recovery in αp. The main stress relaxation mechanisms in the late stage are the globularization of αs and dislocation recovery in αp. The strength improvement after stress relaxation is mainly due to the formation of αs.

The effect of electric field direction on atomic diffusion in NiAl binary alloy was investigated using molecular dynamics simulation method. Different interfacial diffusion models for NiAl binary alloy were simulated, and an electric field was applied on the Ni(110)//Al(110) interface diffusion model to study the effect of electric field direction on the diffusion behavior of Ni and Al atoms. The results indicated that, due to the difference in activation energies for Ni and Al atom inter-diffusion, applying an electric field in the same direction as the inter-diffusion of Ni atoms facilitates the inter-diffusion of Ni and Al atoms.

This review aims for a comprehensive insight into the interfacial reactions and the effects of surface metallization in high temperature die-attach, which is critical in governing the reliability of resultant interconnects of power electronic modules. With the emerging high-temperature filler materials, the interfacial interactions and microstructural evolutions exhibit various distinctive features, which demands detailed examination in order to identify suitable surface finishes. The metallization is not always beneficial to improving the quality and reliability of the interconnects, and consideration should also be given to the cost-effectiveness and manufacturability. The intermetallic compounds (IMCs) formed during interfacial reactions are of prime concerns for an extended discussion, together with the formation of solid solution at interfaces which can also be an important topic to explore. In this work, five commonly-encountered high temperature solder fillers are examined, including high-Pb, Au-based, Bi-Ag, Zn-Al solders and nano Ag paste, the emphasises are put on the interactions with different metallized surfaces in die-attach. The effects of metallization on interfacial reactions and formation of interfaces are discussed. Finally, the recommendations of suitable metallization are outlined to enable cost-effective and reliable interconnects for the related applications.

In order to improve the hydrogen storage capacity of hypereutectic Mg-Ni alloy, the Mg40Ni10 and Mg40Ni8Cu2 alloys were prepared by metallurgy method. The effects of Cu on the alloys’ phase composition, microstructure were studied systematically. The volumetric Sieverts’ method was used to test and analyze the activation performance and hydrogen absorption and desorption kinetic performance of the alloys. It was found that the partial substation of Ni in the Mg2Ni-riched matrix alloy with Cu can change the primary Mg2Ni and eutectic Mg-Mg2Ni morphology of the alloy. With the doping of Cu content, although the activation property of the alloy decreases, the hydrogen storage capacity as well as the kinetic of hydrogen absorption and desorption are improved significantly.

Digital twin and additive layer manufacturing plays a vital role of the fourth industrial revolution. Digital twin is the ideal solution for data-driven optimisation of additive manufacturing challenges. It is helpful in understating, analysing, and improving 3D printing machining process variables and consequently reducing the number of trial-and-error and component’s non-conformance and shorten product development lead time. Furthermore, the development of genuine digital twin still requires more research efforts to develop a thorough understanding of its concept, data management framework, and development techniques. Therefore, this paper aims to capture important data-driven digital twin requirements for additive layer manufacturing through a systematic approach by identifying the requirements, analysing technologies and processes for digital twin development. The main novelty of this research is applying a holistic approach to build digital twin of additive manufacturing process by capturing the requirements from both literature review and world-class aerospace industrial experts. Overall, the captured requirements will not only serve industries as a basis for implementing digital twin for additive manufacturing and modernize existing data management systems but also opens new research areas in the digital twin domain.

Additive manufacturing (AM), also known as three-dimensional (3D) printing, offers great potential to create complex structures layer by layer from computer-aided design (CAD) models. Despite advancements in printable concrete technology, controlling printing quality remains a challenge associated with both the geometric and materials design of the printer nozzle, especially for small-scale printing that may be required by small and medium-sized enterprises (SMEs). Therefore, this study explored the design and development of a robot nozzle system, optimised for a small-scale 3D printing of cement-based structures. Key design considerations included weight, nozzle diameter/shape, material compatibility, flow control, mixing mechanism, temperature resistance, cost-effectiveness, adaptability, safety, and ease of maintenance. Iterative designs were developed, focusing on stress concentration mitigation and material flow optimisation. The challenge of incorporating mixing mechanisms during nozzle designs was discussed, leading to the adoption of an on-demand accelerator spraying system. This method involved a micro-peristaltic pump connected to an accelerator tank, spraying accelerator onto the surface of the deposited material, as the robot moved along its programmed path. Evidently, both the nozzle design and the spraying approach improved the buildability and print quality of the extrusion-based 3D-printed cement-based structures.

Since the first documented modern wearable exoskeleton appeared, the development of wearable exoskeleton could be summarized as three stages: germination, exploration, and innovation. This paper has 5 sections. Section 1 briefly introduces the research background of the modern wearable exoskeleton. Section 2 reviews the classical design cases since the emerging of the concepts of wearable exoskeleton. Section 3 provides a detailed integration of the theory developments on the design methodology of the wearable exoskeleton. Section 4 illustrates a framework of the aesthetic design of wearable exoskeleton by combining Total Design methodology (as a design framework core), QFD, TRIZ and Product Semantics. Section 5 gives a conclusion on the discussion of the design framework as well as the future work.

This review investigates the challenges of Additive Manufacturing using commodity, engineering, and advanced materials, both amorphous and semicrystalline. It explains the reasons behind the weaker mechanical performance of semicrystalline materials compared to amorphous polymers used in the 3D printing process. The performance of 3D printing is discussed to demonstrate the current position of additive manufacturing as one of the promising techniques meeting the requirements of the 5.0 Industrial Revolution, particularly in terms of delivering personalized products. The differences between amorphous and semicrystalline materials on a macromolecular level, including the strength of the single bond in the polymer backbone chain and the effect of electron donation to the backbone, are discussed. Interlayer imperfections are classified into several groups: moisture in the feedstock filament, inconsistent filament diameter, shrinkage of the deposited materials, and, most importantly, crystallization kinetics of semicrystalline materials. Finally, insights on how to achieve properties closer to an isotropic body when advanced semicrystalline materials are printed, in order to overcome layer-layer defects, are provided.

Industry 4.0 has changed the ways in which Small to Medium (SME’s) and Large Enterprise (LE’s) manufacturers and businesses operate. Artificial Intelligence (AI), Bigdata, Edge Computing, Cloud Computing, Internet of Everything (IoE), Fifth Generation (5G) and Information Communication Technology (ICT) allow processes to be optimized, controlled, and monitored in close real-time. These enabling technologies allow manufacturing facilities to collect enormous amounts of data from process lines, such as real-time measurement data, machinery state of health, and cycle time, to accurately plan and report the state of both processes, machinery, and final products. In this work, the research programme focuses on the collected data from process input variables that can be monitored to ensure process outputs and final components conform to design specifications. Current methods of analyzing data, especially in aerospace manufacturing environments, require engineers or process operators with a precise and high skill set to be able to map the results into the appropriate chart and interpret these results. Furthermore, the quantity of data analysis required to monitor process inputs in real-time renders conventional analysis techniques unfeasible. Current development using AI has shown the potential and the capability to detect trends in large data sets using machine and deep learning. It also enables a more precise and automated analysis without human intervention. This paper focuses on determining the feasibility of using a deep neural network (i.e., deep neural networks -DNN) to predict process outputs based on process inputs. A simplified example is presented using data collected from firing a ‘statapult’ with varied configurations, training a deep neural network and predicting future results based on process inputs. Initial results are presented, and the results show promising estimating and prediction capabilities.

The surface quality of components fabricated via laser-based powder bed fusion (L-PBF) is highly dependent on the post-machining technique. This study aims to investigate the microstructure evolution of the turning-affected subsurface layer of the IN625 superalloy manufactured by L-PBF with the assistance of the finite element analysis (FEA). A finite element model with integrated user-defined subroutine VUSDFLD was created for numerical modeling of the dislocation density and grain size evolution due to turning operation. The simulation results regarding grain size and the depth of the affected layer were validated against the experiments. This study shed some light on the metallurgical behavior evolution when turning of L-PBF of nickel-based superalloy based on the proposed material microstructure model.

Laser cladding is an effective method to repair damaged aeroengine blades. However, the heat affected zone of laser cladding reduces the strength of the repaired component. A solution method that strengthening the joint surface by laser shock peening (LSP) before laser cladding was proposed. The process parameters of LSP, such as energy, spot size, overlap ratio, spot path, etc., were determined based on the theoretical analysis; and the specimens were prepared by laser cladding after LSP. The influence of LSP on the strength, hardness and microstructure of the repaired specimens of GH4169 superalloy were researched based on the axial tensile test, metallographic test and hardness test. The results show that the tensile fracture of the specimens which only treated by laser cladding appears on the joint surface; however, the tensile fracture of the specimens treated by both of LSP and laser cladding does not necessarily appear on the joint surface, which indicates that the LSP can effectively improve the strength of the joint surface. The tensile strength of the specimen treated by both of LSP and laser cladding increased by 52.3%, and the elongation of the specimen increased from 0.8% to 9.2%. The metallographic observation showed that the grains of the specimens treated by LSP were refined obviously, and the grain size decreases by 36.5%, which is beneficial improve the strength of the joint surface. The microhardness of the specimen was more uniform and the maximum difference between the two sides of the joint surface decreased by 19.4% when the LSP was added in the repairing process.

Stepped spillways provide an excellent form of energy dissipation and are used in many locations around the world. Effective designs are crucial in improving protection to downstream erosion and providing economic benefits to the stilling basin design. Additive manufacturing (AM) provides a wide range of possibilities of testing complex and varied geometries in fluid flow research at relatively low cost. This research builds upon previous studies in utilising AM in open channel flow applications. This paper presents a comparative analysis between two types of stepped spillway using preceding weir designs in terms of fluid velocity profile, flow rate, water height upstream and downstream; associated fluid flow parameters and experimental observations. For validation and further analysis, computational fluid dynamics (CFD) modelling is conducted to show close comparisons to the experimental results. Conditions are varied to compare the differences between models being sealed and unsealed, allowing for significant side flow. AM technology allows for cost-effective small models to be created, that can significantly improve the design process for larger scale testing and enhances the field of study for experimental fluid flow research.

Sapphire optical components are widely used in various industrial sectors. However, they are currently not available through efficient and highly accurate ultra-precision cutting. Therefore, this paper investigates the effect of cutting speed, a key factor in ultra-precision cutting, on the removal behaviour of sapphire materials. The plunge-cuts tests at different cutting speeds (10, 20 and 30 mm/s) have been conducted. The groove surface morphology, critical cutting depth for ductile-brittle transition, cutting force and tool wear of each plunge-cuts test with various cutting speed test were analysed. The experimental results shown that increasing the cutting speed is beneficial to obtain less defective machined surfaces and increase the critical cutting depth for ductile-brittle transition. However, at the same time, the cutting force increases dramatically in the brittle removal mode during high-speed cutting, which leads to severe tool wear. Therefore, increasing the cutting speed to meet the requirements of ultra-precision cutting and machining within the critical cutting depth is a highly efficient measure for obtaining sapphire optical surfaces.

Quasi-static 3-point bending of additive manufactured sandwich components with auxetic star-4 cores was investigated to obtain information on the influence of geometry parameters of the auxetic structure on the stress distribution of the face sheets. Experiments were carried out on specimens manufactured by fused deposition modelling from a PLA polymer to verify a simulation model for analyses. A hyperelastic material model was used in the finite element models to describe the elastic material behaviour and a hardening model to consider plasticity. Nanoindentation tests on the printed structures were conducted to identify the material parameters with modelling the nanoindentation procedure using the finite element method and applying automated optimisation techniques. This approach enabled an accurate reproduction of the nanoindentation tests in the simulations. The derived models for analysing the auxetic geometry have shown that the stress distribution in the face sheets of the sandwich components can be noticeably influenced with targeted changing the wall thicknesses of the auxetic star-4 structure. The simulations have also made it apparent that more effort is required to take into account the influences of the printing process on the deformation behaviour of the sandwich structure in the simulation model.

As the manufacturing industry continues its shift towards highly complex Industry 4.0 production environments, there is an expected exponential increase and change in the demanded skills and qualifications among employees. However, traditional teaching methods may pose challenges when it comes to applying learned skills in real-life engineering situations, given the complexity of these environments. Recent advancements in technologies enabling virtual co-existence have opened up new opportunities for personalised and immersive services in pedagogy. While Mixed Reality (MR) and, more significantly, Metaverse infrastructure are still in their early stages, researchers and educators have the opportunity to lead the exploration of new avenues for reskilling educators and enhancing student learning experiences. This paper presents research conducted at the University of Malta, focusing on exploring the potential transformative pedagogical effects of MR in specialised Industry 4.0/5.0 engineering training. The paper proposes a framework for developing a Virtual Learning Factory (VLF) using MR technology, grounded in established and effective learning methodologies. The envisioned VLF aims to create an immersive experiential learning environment where engineering students can better adapt to the evolving industrial landscape, preparing them to excel in the dynamic era of advanced manufacturing. Additionally, the research delves into the potential impacts of MR-based training on enhancing training precision and efficiency.

Submerged Arc Additive Manufacturing (SAAM) is a process known for its high material deposition characteristics, and since it is based on Submerged Arc Welding (SAW), it is expected to obtain thicker material depositions. In this work, an algorithmic framework has been developed which helps product designers or the user by taking their expectations of the bead width according to their requirement, and the algorithm suggests the optimal input process parameters which would help obtain an optimal bead width and optimal use of energy, minimizing the need for post-processing. The framework incorporates penetration depth, a critical factor for proper interlayer fusion. The framework was compared with a Genetic Algorithm (GA) output with similar GA parameters for a single run to evaluate its effectiveness. The proposed framework achieves a 93.7% accuracy in bead width prediction and a 27.5% reduction in energy input per unit length compared to the GA. This user-friendly tool empowers novice SAAM users and manufacturers to optimize deposition and energy efficiency.

Wireless Sensor Nodes (WSNs) have developed significantly over the years and have a significant potential in diverse applications in the fields of science and technology. The inadequate energy accompanying with WSNs is a key constraint of WSN skills. To overwhelm this main restraint, the development and expansion of effective and reliable energy harvesting systems for WSN atmospheres are being discovered. In this research, low power acoustic affordable and clean energy harvesters are designed and developed by applying different techniques of energy transduction from the sound available in the surroundings. Three acoustic energy harvesters were developed based on piezoelectric phenomenon, electromagnetic transduction & Hybrid respectively. The CAD modelling, lumped modelling and Finite Element Analysis of the harvesters were carried out. The voltages were obtained using FEA for each Acoustic Harvester. Characterization of all the three harvesters were carried out and the power generated by piezoelectric harvester, electromagnetic harvester and Hybrid Acoustic Energy harvester are 2.25x10-9W, 0.0533W and 0.0232W respectively.

Micro MIM is one of the manufacturing methods for medical devices, which has seen a rapid increase in demand in recent years, but due to the porous structure of the product, there are concerns about insufficient strength due to low density. Ultrasonic-assisted surface reinforcement was proposed to supplement the strength by hardening the surface and improving bending stiffness in this study. Ultrasonic-assisted pressing was performed to verify mechanism for the surface hardening by comparing MIM and rolled specimen. The materials used are pure copper MIM. It was found that MIM specimen have a characteristic in which strain is concentrated near the surface compared to rolled specimen. This suggests that the cause of the concentration of strain on the surface may be the absorption of ultrasonic energy by the pores inside the material due to sound and shock absorption properties of the porous structure.

Electrochemical machining (ECM) is a non-contact type machining technique in which, material is removed from the workpiece by the process of electrochemical dissolution in the presence of an externally applied electric field. Electrochemical turning (ECT) is a variant of ECM which closely resembles the conventional turning operation in configuration. ECT produces parts without burrs, thermal or mechanical residual stresses, and generally possesses a good surface finish. According to the classical theory of electrochemistry, the rate of material removed from the anode surface depends upon several process parameters such as: applied potential, electrical conductivity of electrolyte, gram electrochemical equivalent and mass density of the anode material, and the interelectrode gap. However, in ECT, workpiece rotational speed is also a key parameter which significantly influences the machining rate, but no analytical or empirical relationship in existence takes account of it. In the present research, a numerical model is developed to study the influence of rotational speed in ECT. This model numerically approximates the distribution of current density on the anode surface in two-dimensions without considering the hydrodynamics of the electrolyte flow. For a specific set of other process parameters, simulation results suggest a positive correlation between the machining rate and rotational speed.

Nowadays, satellite systems are experiencing noticeable disruptive issues due to the single functionality, high cost of operations, and limited adaptability. This paper presents a satellite mission control system with RF duplex communication, which gives multiple functionalities and health monitoring systems with solar tracking capability. This aims to present a flexible and affordable solution called the Remote Sensing Mission Sentinel Pro Platform. The quantitative approach is used and implemented to trans-receive data from space and pass it to the ground station. Arduino-based prototype uses the nRF24L01 module with an antenna at the ground station to trans-receive satellite data has been developed. Testing and verifications of the developed platform prototype indicated that satellites could monitor key health parameters, including temperature, humidity, and battery charge capacity.

Conventional commonly used titanium stamping techniques like hot forming and superplastic forming each have distinct disadvantages. Hot forming usually leads to limited formability and significant springback, whilst superplastic forming often results in long cycle times, high energy use, and costly tooling. A novel, energy-efficient, and cost-effective Heat Stamping process emerges as a promising solution. Two types of Ti6Al4V components, cup-shaped and U-shaped, were produced using the novel Heat Stamping process, and their properties were examined. A defect-free cup-shaped component achieving a considerably high draw ratio of up to 1.8, was successfully fabricated. A moderate enhancement in the hardness of the component indicated a superior post-form strength achieved by Heat Stamping. Further analysis of the U-shaped components shows that the one produced using the novel method demonstrated a notable reduction in springback angle, from 4.8° to 0.7°, highlighting the potential of H eat Stamping in achieving high shape accuracy for near-net-shape forming.

Machining of additive manufacturing (AM) process results in excessive consumption of the cutting power due to the high strength and hardness of the material produced that led to high cutting forces and short tool life during machining process. This paper aims to investigate the effect of cutting conditions and coefficient of friction on the cutting forces, during finite element analysis (FEA) of an orthogonal cutting of AM Ti6Al4V alloy bar. The FEA simulation considers three different experiments at low, medium, and high cutting conditions. The result shows that as the depth of cuts gets deeper and the cutting speed increases, the cutting forces were found to increase, leading to serrated or segmented chips formation. A cutting force of 1300.36N was observed at a cutting speed of 150 m/min and a coefficient of friction of 0.9. The cutting force was found to be weaker at the higher shear plane angle of 42.2o and higher at a smaller angle of 37.57o. The coefficient of friction was observed to be insignificant at lower value of 0.09 and was seemed to affect the cutting force at value around 1.

Additive manufacturing (AM) is treated as a significant contributor to sustainability due to lower energy consumption, less material usage and reduced number of wastes generated when comparing with traditional manufacturing technologies. Currently there is a lot of commercial applications of such new technology in number of industry segments. However, such sector as high voltage engineering still struggles with number of challenges when considering additive manufacturing. In products working in high voltage environment, very often, in addition to mechanical loads there are demanding conditions, as elevated temperature and presence of insulation oil or gas. This requires a special approach to printing quality of the printed structures without internal voids and in case of metals, with improved electrical conductivity. In the paper, few examples of additive manufacturing applications in area of power products have been presented, including printed transformer insulation, printed copper, and application of AM for spare parts. For each case, the main challenges have been discussed.

Magnesium (Mg) alloys are very popular among the biomaterials for biodegradable bone implants due to their suitable properties matching with that of human cortical bone. However, their poor corrosion resistance in biological fluid is a major constraint to become an ideal choice for bioimplants. The corrosion resistance of Mg-alloys is further retarded with microstructural impurities such as micro-pores, micro cracks, heterogeneous distribution of alloying element etc., which is commonly present in as-cast Mg-alloys. In present study, Friction stir processing (FSP) has been performed on Mg-2Zn alloy to refine the microstructures as well as to develop Mg-Zn-HA composites by using HA powder reinforcement. HA powder reinforcement was added using micro-grooves and multiple FSP passes on as-cast Mg-2Zn alloy having average grain size of 63.86 µm. Filling HA powder in 2-grooves and using 3-pass FSP, a refined microstructure having an average grain size of 7.15 µm and homogeneous distribution of HA powder was obtained for the developed Mg-Zn-HA composite. The Mg-Zn-HA composite developed with 3-pass FSP treatment has shown significant improvement in tensile strength and corrosion resistance as compared with as-cast Mg-alloy.

Automation is crucial for the future of the industry as it enhances efficiency, quality, and accuracy while reducing operating time and the occurrence of human errors. Establishing an automated factory requires significant resources, including robot installation, worker training, program development, and ensuring quality and safety measures. This paper presents a study on automating the testing process for an aerospace company aiming to enhance productivity and minimise errors. The study aimed to achieve full task automation using a Universal Robotics Arm (UR5), which undertook the tasks of retrieving, inserting, securely locking, and removing the six connectors into the equipment, effectively executing the entire process. In initial trials, wireless connectors exceeded expectations, achieving 16 cycles in 2 hours. The inclusion of cables brought about significant challenges, particularly in terms of cable entanglement and concerns regarding the durability of connectors. Proposed solutions include improving the rack system and refining the gripper’s functionalities. This highlights the project’s potential for transformative advancements in aerospace manufacturing.