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This work simulated a modified three-dimensional single-track finite element model and a temperature discrimination mechanism in order to investigate the variation of temperature field in stainless steel and the effect of technological parameters on the coating. Through theoretical calculation, the distinction between the thermal characteristics of CoCrCuFeNi powders and CoCrCuFeNi alloys was made to improve the precision of simulation findings. In addition, to more precisely represent the heat transfer, an asymmetric Gaussian was used to distributed heat source and exponentially change the laser energy to account for the attenuation of laser power along the z-axis. The absorption rate of the laser beam at different temperatures of the material was also considered. The data was curve-fitted to examine the impact of laser power and scanning speed on the cladding layer morphologies. The laser power was found to be proportional to the width and depth of the clad layer, whereas the laser scanning speed was found to be inversely related to the width and depth of the clad layer. The simulation results were basically matched to the experiment. [ABSTRACT FROM AUTHOR]

Wire arc additive manufacturing (WAAM) is one of the most productive metal additive manufacturing methods. One of its most promising applications holds in the manufacturing of difficult-to-cut materials where production costs can be reduced with minimizing the time of machining and total tool costs. To develop a correct WAAM, technological processes for manufacturing complex-shaped components welding torch path corrections and welding power corrections have to be made especially in critical sections such as corners and sharp edges. A predictive mathematical model of the material cladding during the WAAM process has been developed for the purposes of generating an optimal toolpath of the WAAM clads. This predictive mathematical model is simplified to reflect the important physical phenomena in the weld pool but also to optimize computing time. In this paper, the principle of the mathematical model is described, and its functionality is verified by the welding experiments with five different welding power settings. For the initial calibration of the model parameters single straight-line weld clads with 5 different welding power settings (wire feeds) ranging from 5.0 to 8.6 m/min were investigated. 3D scans of these welded samples are used for the verification. With the calibrated simulation model, it was possible to predict the precise shape with a maximum deviation circa 0.20 mm. The start portions of the weld clads seem more complex having the deviation circa 0.30 mm. These are valuable results as the WAAM technology is generally considered to be reasonably rough. [ABSTRACT FROM AUTHOR]

In the dynamic landscape of modern manufacturing, the pursuit of efficiency, reliability, and optimal performance has prompted the integration of cutting-edge technologies. Among these, digital twins (DT) have emerged as transformative tools, offering a virtual representation of physical processes, systems, and equipment. This paper delves into the pivotal role of digital twins in advancing the monitoring and supervision of manufacturing processes, focusing specifically on process digital twin (PDT) and its application in the domain of froth flotation in minerals processing. Our data-driven digital twin, replicating the behavior of a flotation cell, was developed using a combination of industrial and simulation data anchored by Artificial Neural Networks. This approach provides precise process emulation of the flotation process. Industrial evaluations of the AI model within the Digital Shadow demonstrated an overall 94% accuracy in estimating insightful information regarding the flotation cell operations with 2 s in response time. This research significantly contributes to the practical implementation of digital twins in industrial processes, highlighting their potential to revolutionize process control and enhance efficiency in the industrial sector. [ABSTRACT FROM AUTHOR]

Fiber composite materials exhibit exceptional specific stiffness and strength compared to traditional engineering materials. Nevertheless, automating the handling of limp flexible materials like fabrics remains a challenging process, often relying on multi-stage manual operations for hand layups. In this study, carbon fabric properties were initially characterized through standard experiments to develop and calibrate a finite element (FE) model. The FE model was subsequently validated against real-world pick-and-place tests involving soft robotic grippers. The validation results demonstrated a high correlation between the FE model and experiments, achieving an average accuracy of 97.2% for fabric projected area and 84.6% for fabric vertices' displacement. Additionally, the FE model was used to design, evaluate, and optimize alternative automation strategies. It was discovered that a convex surface improved fabric projection area and placement accuracy by 5.9% and 1.9%, respectively, compared to a concave surface with the same curvature radius. Larger concave surfaces contributed to increased projected area and placement accuracy as well. Longitudinal pick-and-place operations also enhanced the projection area and placement accuracy compared to transverse handling processes. Achieving successful fabric pick-and-place operations necessitates a comprehensive system's approach, considering the interaction between grippers, fabric, and mold surface. The FE model developed in this study will be further employed by the current research team in designing innovative compliant grippers tailored to complex mold surface geometries and specific fabric material requirements. The presented FE model offers valuable insights and paves the way for rapid, efficient, cost-effective, and secure implementation of automation solutions for handling limp flexible materials. [ABSTRACT FROM AUTHOR]

Powder bed fusion (PBF) is an additive manufacturing (AM) technique that holds a great promise for alumina ceramic materials to be processed in a one step. To ensure an effective outcome, the powder material should be thoroughly tailored, and the process parameters should be appropriately investigated. These process parameters include laser power, scanning speed, hatching space, and scanning strategies. The alumina powder has been tailored and modified to be appropriately used for PBF using the spray-drying technique, and the process parameters have been predicted and selected using a developed numerical model. Different scanning speeds of 100, 200, 300, and 400 mm/s have been considered, and the other parameters have been numerically predicted. The results demonstrated that spray drying is an effective technique for tailoring the characteristics of alumina powder, such as particle shape, particle size distribution, flowability, and absorptivity, making it ideally suited for PBF processing. Furthermore, the developed numerical model demonstrated outstanding reliability in predicting the most effective laser power and hatching space for different scanning speeds, resulting in significant cost and time savings when compared to relying solely on experimental trials. Employing a scanning speed of 400 mm/s yielded a significant improvement in relative density and quality of the printed samples surpassing other scanning speeds. Moreover, this speed effectively addressed various challenges encountered by other scanning speeds. Following the optimization of process parameters, it was determined that a relative density of 94.5% could be achieved by utilizing a scanning speed of 400 mm/s, a laser power of 210 W, and a hatching space of 30 µm. However, the evaluation of mechanical performance revealed that while the microhardness of the printed alumina samples matched the values reported in the literature, the attained compressive strength fell significantly below the values reported in the literature. [ABSTRACT FROM AUTHOR]

Multi-material fused deposition 3D printing has the unique ability to maintain complex shapes and add special properties. However, the narrow selection of consumable materials, low printing efficiency, and poor performance of the finished products limit the application scope of this technology. In this paper, we propose a twin-screw extrusion 3D printing system that can print a variety of powdered or granular materials, including environmentally friendly biomass particles, metal particles, and thermoplastics, and that enables the mixing of heterogeneous materials. Then we investigate the heat transfer and rheological properties of the system's material extrusion process. Through the coupled thermal-fluid-solid multi-physical field simulation of the nozzle system, we qualitatively and quantitatively study the transport law and thermal flow field distribution characteristics of the material within the extrusion system, analyze the transport and melting mechanism of the hot melt in the runner during the extrusion process, and obtain the mechanism of the influence of the structural design parameters and the 3D printing process parameters on the transient flow field characteristics and mixing performance. When the screw's outer diameter is 20 mm and the speed range is 5–25 r/min, the nozzle extrusion flow rate is 2.45–20.15 mm3/s, and the printing efficiency is 3–4 times that of traditional wire printing. The flow field characteristic parameters are optimal when the screw lead is 24–36 mm, and the material extrusion effect is best when the rotational speed is 8–15 r/min. The heat flow field distribution in the extrusion system is stable, the speed distribution is reasonable, and the temperature field distribution is uniform. There is no solution reflux or overflow at the nozzle, the nozzle is not blocked, and the material can be extruded at constant temperature and pressure. The strength of the twin-screw is within the allowable range, the mixing performance is good, and the material can be transported forward with positive displacement. The maximum thermal deformation of the nozzle is 0.09861 mm, which is much smaller than the maximum deformation precision of 0.2 mm, indicating that the screw and nozzle are reasonably designed. The simulation proves the reasonableness of the calculation results. [ABSTRACT FROM AUTHOR]

Conventional explosive welding is performed in the atmosphere. In addition to causing many hazardous effects (air shock wave, vibration, and noise), air medium also affects the welding quality. To study the influence of the vacuum environment on the above problems, this study conducted CP-Ti/Q235 explosive welding in the vacuum (0.1 atm), and set another experiment in the atmospheric environment as a reference. The results showed that the vacuum environment significantly reduced the hazardous effects. Compared with the atmospheric environment, the low density of the gas medium attenuated the shock wave (69.27%) during the explosive welding, resulting in reduced levels of vibration (74.46%) and noise (45.31%). Microstructure analysis found that in both environments, the wavelength and amplitude of the waveform interface were remarkably different at the end portion, and the overall waveform obtained in the vacuum was more uniform than that in the atmosphere. Through the two-step simulation, the pressures of the interstitial gas shock wave were respectively 15.4 and 1.66 MPa under the atmospheric and vacuum environments. Therefore, the interstitial gas shock wave affected the movement of the flyer plate, causing welding instability, especially in the atmosphere. Furthermore, the participation of the gas during the wave formation led to the appearance of the pores and microcracks. In contrast, the vacuum environment effectively decreased the micro-defects of the bonding interface, improving the welding quality. This study revealed the detailed advantages of the vacuum environment and provided a reference for explosive welding in urban areas. [ABSTRACT FROM AUTHOR]

Grinding is widely used for machining high-precision parts, but grinding wheel wear and grinding wheel vibration significantly impact the surface quality of the parts in the process of machining. However, the effect of those two factors on the grinding surface has not been considered simultaneously in most grinding surface topography simulation studies. Hence, the paper conducts a simulation study of grinding surface topography with the consideration of the two factors. First, the actual topography of the grinding wheel surface is measured, and the surface topography of the grinding wheel is modeled accordingly. Second, the kinematic analysis of grinding is carried out and a mathematical model of grinding surface topography simulation, which involves grinding wheel wear and grinding wheel vibration, is constructed. Finally, grinding machining experiments are conducted to compare and analyze the surface topography and surface roughness of the actual and simulated grinding surfaces. The results show that the average relative errors of the four roughness parameter values between the simulated and actual grinding wheel surfaces are all below 2.5%. With the consideration of those two factors, the average relative errors of the surface roughness parameter values between the actual grinding surface and the corresponding simulated grinding surface are all less than 13.5%. This verifies the correctness and effectiveness of the method proposed in this paper. Improving the accuracy of the simulated grinding surface topography allows for better optimization of the selection of grinding machining parameters. It helps to precisely predict the surface topography and surface roughness of the grinding surface. [ABSTRACT FROM AUTHOR]

Nowadays, the punching damage tools have become widespread which greatly increased the production cost. AISI D2 punch used to make a hole through S500 MC sheet metal has premature damage. Various parameters such as high speed and non-optimized clearance are behind their failure. In this study, a numerical simulation takes place to understand the punching process and to find the punch damage causes. The aim of this study is to investigate the impact of some parameters on punching force and suggest some solutions. It was uncovered that too high punch-die clearance distinctly decreases the punch force. [ABSTRACT FROM AUTHOR]

In this study, the temperature evolutions in the laser direct energy deposition process of Fe-based metallic materials are numerically investigated using the finite element method. The effects of heat input method and the model reduction strategy based on the lumped approach in the simulations were studied numerically. The simulations were carried out following the depositions of single beads, single layers, and multiple layers. The results of the simulations were compared with the temperature evolutions obtained in the experiments as well as the melt pool shapes observed in the experiments. Based on the numerical and experimental results, a numerical modeling strategy is proposed for estimating the temperature distributions in the laser direct energy deposition processes in a time-efficient manner, while maintaining the accuracy of the simulation. The proposed simulation strategy used rough simulation time steps for estimating the overall temperature rise, in addition to using only a few fine simulation time steps for predicting detailed temperature distributions at certain simulation times of interest. The proposed strategy allowed the FE model to reduce calculation time by more than 3.8 times while also accurately simulating the detailed temperature of the region of interest. [ABSTRACT FROM AUTHOR]

The microstructure of 6xxx aluminum alloys deeply affects mechanical, crash, corrosion and aesthetic properties of extruded profiles. Companies, especially in the transportation sector, require control over the grain structure in order to ensure the quality and the performance of the products. A main challenge for the extrusion companies is to accurately predict the profile microstructure at the design stage, trying to limit the formation of coarse grains and, consequently, the reduction of the mechanical properties of the component. In this work, the modeling of the stored energy, driving force for the recrystallization, was carried out and implemented within the Qform Extrusion FEM code. A novel approach for the evaluation of fibrous and recrystallized microstructures in 6XXX aluminum alloy profiles was proposed and tested in a campaign of experiments involving the extrusion of AA6082 round bars under several die designs and processing conditions. The outcomes proved the good accuracy of the recrystallization predictions during the extrusion of AA6082 aluminum alloy. [ABSTRACT FROM AUTHOR]

Wire arc additive manufacturing (WAAM) is widely studied due to its high deposition rate. However, WAAM samples have poor forming quality compared with other additive manufacturing technologies. The quality of sample formation is directly related to the time required for subsequent mechanical processing. Hence, cycle time can further be reduced by controlling the forming quality. Additionally, better forming quality results in less material wastage. Therefore, the forming quality of samples has always been the focus of WAAM. In this paper, the droplet transfer process of the WAAM is shot with a high-speed camera. This article attempts to explain the WAAM forming process from the perspective of droplet transfer and evaluate the influence mechanism of droplet transfer on the side surface forming quality. High-speed photography is used to extract the molten pool size and droplet transfer frequency. The study also explored the variation of these factors with wire feed speed and number of layers. A two-dimensional droplet transfer model is established based on the results of high-speed photography to study the droplet transfer process. Next, the 3D sample model is built to obtain the roughness of deposition samples. Finally, the relationship between the forming quality and droplet transfer process is studied through the fitting planes. The relationship model of wire feeding speed, molten pool length/droplet transfer frequency, and roughness is obtained. The roughness of the side surface increases with higher wire feed speeds when the wire feed speed is 5.5–6.5 m/min. However, at a wire feed speed of 7.0 m/min, the roughness of the side surface suddenly decreases. The droplet transfer motion rule is then used to explain this change in forming quality. [ABSTRACT FROM AUTHOR]

High-speed motorized spindle is an important component of machine tool, and the influence of heat and deformation generated in the working process on the machining accuracy cannot be ignored. In order to reduce the temperature of the motorized spindle in the machining process, this paper first explores the influence of the flow rate of the motorized spindle cooling water on the cooling water jacket and the overall temperature change. The results indicate that when the flow rate exceeds a certain range, the overall temperature no longer drops, so there is an optimal flow rate in the choice of flow rate. Secondly, to solve the problem of uneven axial temperature distribution of the traditional spiral water jacket, four kinds of cooling water jackets with different structures were proposed. The simulation results show that the difference in temperature distribution inside the serpentine water jacket is small, the overall temperature was reduced by 1.8 °C and the pressure drop was reduced by 62.54 kPa. It shows that the serpentine cooling water jacket has better cooling performance and can effectively reduce the thermal deformation of the motorized spindle shafting, so as to achieve the purpose of improving the machining accuracy. [ABSTRACT FROM AUTHOR]

The non-destructive full-field non-contact thermographic technique is applied for non-destructive flaw detection of the welded joints, in real-time and offline configuration. In this paper, a thermographic procedure for real-time flaw detection in manual arc welding process is presented. Surface temperature acquisitions by means of an IR camera were performed during arc welding process of 8 specimen both for calibration and validation of the numerical model. The investigated variables are the technique (manual stick arc (SMAW) and gas arc (GMAW) welding) and the joint shape (butt and T joint) for steel joints, in sound conditions and with artificial flaws. Numerical simulation of welding thermal transients was run to obtain the expected surface temperature fields and thermal behavior for different welding parameter configurations. Hardness measurement and micro-graphic analysis were performed to validate numerical simulation results. The real-time thermographic study of the weld pool gives direct indications of anomalies; local studies of the thermal transient and thermal profiles can detect some kind of flaws; microstructural analysis of Heat-Affected Zone (HAZ) and surrounding areas higlights the presence of austenite and martensite distribution which justifies the thermal transients and thermal profiles for different welding configurations. Comparing real-time IR acquisition of the welding process with simulated thermal contours of sound processes provides information of presence of some kind of flaws. Since most of the flaws are generated in the weld pool, it is possible to recognize anomalies directly from the thermal acquisitions or with post-processing the acquired data. [ABSTRACT FROM AUTHOR]

Vacuum brazing is a black box process, so component distortion that occurs during the heat treatment is difficult to prove experimentally. Thus, a novel FE-model was developed in ANSYS Workbench to calculate the time and location resolved component deformation of AISI 316L/B-Ni2 brazing assemblies. In this regard, a new method of radiation and contact modeling was developed that enabled a significant reduction of the calculation times and solved the convergence issue for simulating the distortion of large-scale, thin components. The results showed that the component deformation during heating can be easily kept in the elastic range and can be almost completely eliminated by using a geometry-dependent soaking time. In contrast to this, high cooling rates were found to result in thermally induced stresses well above the elastic yield limit, causing significant component deformation. With further cooling, the deformation decreases significantly, but it depends on the initial stress state, the geometry, and the cooling rate whether the deformation can be completely leveled out during the shrinkage of the component. Thus, the initially high cooling rates were identified to be responsible for the final distortion. Furthermore, this was highly affected by the local position in the heating chamber. The simulation results were used to design a fixture for vertical positioning, which reduced the max. temperature difference in the brazing assembly from 141 to 79 °C, the max. interim distortion from 275 to 31 µm, and the final distortion from 14 to 8 µm. [ABSTRACT FROM AUTHOR]

This paper explores the concept of autonomous decision rules of Industry 4.0. The goal is to model and simulate a production system in which products autonomously choose the resource in which they will be processed based on shortest completion time (shortest queue length). For validation and benchmark, a production system previously presented in the literature is modeled. The performance of the autonomous model is evaluated in comparison to a model with dedicated lines for each product. In the previous work considered, a specific interarrival function and only deterministic parameters for the processing times are used, with no consideration of setup times. After validation, the proposed models are simulated with other parameters (different probability distributions for interarrival and processing times) and are extended to include machine setups, according to different rules. Reductions in total throughput times and their variability were observed for the systems with autonomous products, when compared to those with dedicated lines, which indicates greater responsiveness and stability of the shop floor. An optimization model for scheduling was also proposed and applied to the same system and input data of the simulation of autonomous products, for comparison. The results showed that the proposed decision rule based on the queues' length, used in the simulation, can yield solutions of good quality, close to the optimal solution. This paper contributes to extend and generalize the results of the literature and the discussion about variability seeks to motivate organizations to implement systems with autonomous products. [ABSTRACT FROM AUTHOR]

The smart shop floor is the basic unit to realize intelligent manufacturing. Digital twin (DT) technology is a virtual presentation of the physical world and provides model support for shop floor layout, production scheduling, and production simulation. However, the complex connection and interaction of multiple devices, materials, and information poses a great challenge for the design and production simulation of the smart shop floor, and it is a major difficulty in the application of DT technology to build a multi-scale DT model of shop floor resources to accurately simulate the manufacturing system and guide the actual production process. Inspired by this need, this paper presents a multi-scale, multi-level digital twin modeling method for production resources of shop floor. First, the DT model of production resources is formally represented as four parts: geometric model, physical model, behavioral model, and rule model. Second, for implementing the interaction of different production resources, the connection and interaction mechanism is proposed. Last, taking the DT model of a micro-assembly shop floor as an example, the feasibility of the proposed method is verified, and a prototype system is developed. The implementation of the micro-assembly shop floor application case provides engineers with guidance for building a reliable, reusable DT model of production resources. [ABSTRACT FROM AUTHOR]

Bulk metallic glass (BMG) is one of the predominant materials that are progressively used in the aerospace, medical devices, electronics, sporting goods, and engineering materials. Making of components by BMG is still confrontation. Conventional methods of machining are restricted in use due to more tool wear and slower processing efficiency. Non-traditional methods of machining have been widely used for processing hard materials. Wire electrical discharge machining (WEDM) is one among the promising approaches of machining for hard and conductive materials, especially for the new BMG metal material. The preliminary aim of this exploration is to predict the temperature field distribution using the modified Gaussian heat source mode during WEDM multi-pulse discharge process. The effects of various variables (pulse off time and peak current) on the pit depth and surface roughness were investigated. The influence of the main parameters on the machining performance was investigated using Taguchi's orthogonal arrays. The excellent surface quality is obtained at the optimized condition of a pulse on time of 4 μs, pulse off time of 25 μs, and a peak current of pulse on time. [ABSTRACT FROM AUTHOR]

This paper adopts electrochemical machining (ECM) to machine spiral-shaped deep holes, which are difficult to machine by conventional machining methods. Firstly, a cathode structure with two working teeth with increasing spiral end face dimensions was designed. The interstitial flow field and interstitial bubble field were modelled, and simulations were carried out using COMSOL simulation software to realise the optimisation of the cathode working teeth structure. The results show that the cathode structure with four incremental baths provides good uniformity of gap electrolyte flow, and the flow rate is significantly increased, reaching over 6 m/s. The concentration of bubbles in the interstitial electrolyte is significantly reduced, with a reduced rate of 47% and a smaller bubble distribution area. Processing accuracy and surface quality are effectively improved. Secondly, ECM experiments were carried out. The experimental results were analysed using the response surface method for multi-objective optimisation. The optimised process parameters were obtained as follows: inlet pressure 0.7 MPa, machining voltage 10 V and feed rate 0.9 mm/min. Finally, a qualified sample was machined using the optimised process parameters. The dimensional deviation is 0.28 mm and the roughness is 1.398 μm, which meets the product requirements. This simulation and optimisation method effectively shortens the cathode development cycle and reduces production costs. [ABSTRACT FROM AUTHOR]

The carbon fiber–reinforced polymer (CFRP) structure in the aviation industry is typically subject to low-velocity impact damage during the assembly process, which can have a catastrophic effect on the strength and durability of composite structures. To reduce the impact of this damage on the composite structure, a composite laminate with a rubber protective layer has been proposed and proved to be effective in reducing the low-velocity impact damage. The delamination volume of the composite laminate with a rubber layer under low-velocity impact loadings was predicted in this study using a back-propagation neural network (BPNN). Various factors were considered, which can affect the delamination damage volume including impact diameter, rubber layer thickness, impact velocity, and specimen area. To generate enough training data, hundreds of finite element models have been simulated with various factors mentioned above as input data. Low-velocity impact tests have been conducted to validate simulation results. Simulation results were processed into delamination volume by python as output data, which can describe the damage degree of the composite. These input and output data were trained by a back-propagation network until the learning results meet the expected accuracy. The prediction error with simulation results and experiment results were within 4.3% and 11.2%, respectively. [ABSTRACT FROM AUTHOR]

This paper explores the possibility of applying reverse engineering to flexible coupling spare parts through additive manufacturing. Although couplings' simplicity makes them go unnoticed, they connect elements that transmit power between two shafts, thus being an essential component for most of the machinery currently used in the industry. In this study, flexible couplings with different infill density (60% and 80%) were 3D printed by the fused filament fabrication technique. The original and the additive manufactured couplings were modelled to compare their compressive response and energy-absorbing characteristics, and experimental tests were performed to validate finite element analysis. To derive an optimal material distribution within coupling structure, a generative design approach was conducted through nTopology software. With this novel simulation-driven design, it is possible to reduce the weight of the redesigned part up to 15.8% by defining the wall thickness of the internal structure based on the results of finite element simulation, while maintaining its functionality. Moreover, an economic-environmental study was carried out. Results ensure that the 3D printed prototypes are suitable for replacing the original one under its current operating conditions. Additionally, the economic study shows that the redesigned couplings allow companies to save more than €2700 per coupling in relation to CO2 emission payments. [ABSTRACT FROM AUTHOR]

Mixing in extrusion is a vital part of achieving consistent and high-quality extrudates, with residence time being an elucidative measure of the mixing performance. Recent studies around numerical modeling of residence time distributions in single-screw extruders appear to consider flooded extruders mainly. This paper introduces a new and general CFD model to characterize the extruder fill length and residence time distribution for a viscoplastic ceramic material in a starve-fed extruder, including free surface tracking. The CFD model simulates a pulse-injection test, where a fluid parcel is injected at the inlet, with subsequent outlet concentration measured over time. The study includes material characterization and model validation based on laboratory tests. Results quantify the impact of accounting for the partially filled extruder instead of assuming it to be flooded, addressing the potential error when only considering simple analytical approximations to calculate system average residence times. Results further show the ability to fit simulation results to more simple analytical models. This underlines the importance of including the entire extrusion system and forming the basis for further work toward enabling real-time model predictions in starve-fed extrusion systems. [ABSTRACT FROM AUTHOR]

This paper investigates the thermal-pseudo mechanical (TPM) model's residual stress prediction capability for its utility in developing friction stir processing (FSP). Specifically, two FSP tests under different processing conditions were conducted, and the corresponding simulations were carried out to verify if the TPM model can predict residual stresses for various tool radii and workpiece materials. The model successfully predicted residual stresses with an error less than 4% for one of the tests but failed to work for the other test. Further simulations under different FSP conditions proved that the TPM model works for cast aluminum alloys and wrought aluminum alloys. In addition, the large FSP tool used was found to be the reason for the model's failure on one of the tests. This indicates that there is a range of tool radii for which the TPM model is applicable. As a solution, this paper suggests modifications to the TPM model based on calibration to the FSP test temperatures. The resulting residual stress prediction is accurate and differs from the experimentally characterized stress values by only 6.5 MPa. The calibrated TPM model requires FSP to be carried out when using a tool with a different radius. Following that, the effect on residual stresses due to changes in the other process parameters, such as the tool traverse & rotation speeds and the clamping conditions, can be predicted. [ABSTRACT FROM AUTHOR]

In longitudinal vibration-assisted milling (LVAM), the tool flute is retracted from the bottom of the machined surface along the axial/longitudinal direction. Nevertheless, there is still a limitation in the knowledge of LVAM during Ti-6Al-4 V cutting regarding the cutting forces pattern in analysis using finite element (FE) simulations and analytical prediction comparatively. This study developed an FE model of the cutting force using ABAQUS and a mathematical model of the cutting force using MATLAB. The FE model was developed based on the Johnson–Cook plastic deformation and the Johnson–Cook damage model. The analytical prediction was developed based on the fluctuated undeformed axial chip thickness and the influence of the longitudinal vibration on the undeformed chip thickness. According to this comparative study, the analytical prediction of the cutting force coded in MATLAB has remarkable similarity with the FE simulation model cutting force. The experimental cutting forces were also carried out to validate both the FE simulation model and the mathematical model. According to the comparison results in the LVAM, the FE simulation model has higher quantitative error than that in the mathematical model, with the highest error in the mathematical model being about 7.146% and the highest error in the numerical model being about 9.913%. In addition, a comparative study between LVAM and CM in terms of the experimental cutting temperature, machined surface morphology, and chip morphology was also carried out. In evidence, LVAM provides better machining performance than CM. [ABSTRACT FROM AUTHOR]

Electromagnetic stirring (EMS) is one of the most used techniques for the preparation of aluminum alloy semi-solid slurry. Compared with other EMS methods, the intermediate frequency electromagnetic stirring (IFEMS) method can achieve the stirring of semi-solid slurry by adjusting the process parameters and realizing the heating of the material. In this study, a 2D symmetric model with coupled magnetic field-flow field simulation was used to study the effects of the input current and input frequency of the induction coil on the magnetic induction intensity and EMS effect in the slurry. The increase of the input current significantly increased the velocity of the slurry at each position but had little effect on the change of the flow direction. The increase of the input frequency improved the stirring effect in some positions of the slurry within a certain range, but the overall intensity of the slurry motion decreased, and the edge effect of the magnetic field and velocity field enhanced. The input current of the induction coil should be less than 100A, and the input frequency should be around 2000 Hz. The experimental platform of the IFEMS was also built to investigate the influence of the input current and stirring time on the microstructure of the prepared samples, and the stirring effects at the center and edge positions of the slurry were compared. Lastly, the microscopic near-spherical structure with an average diameter of 46 μm was obtained using this method, which proved the feasibility of IFEMS for the preparation of aluminum alloy semi-solid slurry. [ABSTRACT FROM AUTHOR]

This paper deals with the problem of production planning and control (PPC) within hybrid manufacturing-remanufacturing systems (HMRSs), in which demand is fulfilled by either remanufacturing of returned items or manufacturing of new ones. It investigates how companies could benefit from changeable system settings with two production facilities operating in a stochastic and dynamic context. The rationale of such a system arises from its convertibility features that help to adapt the production process to internal (e.g., failures) and external (e.g., limited returned items) constraints. In this respect, we propose an integrated control policy that minimizes the long-term total cost by determining production and disposal rates as well as the switching strategy between manufacturing and remanufacturing modes. To tackle the problem, numerical techniques and optimal control theory are combined to characterize the control policy. A simulation-based approach is then used to optimize the resultant control parameters minimizing the total cost and to carry out sensitivity and comparative studies. The results illustrate the robustness of our approach showing its capability to assess the dynamic behaviour of integrated decisions and show that our proposal is more cost-effective compared to existing policies applied for different system settings with two facilities. [ABSTRACT FROM AUTHOR]

Compacted graphite iron has been used more and more in industry because of its excellent mechanical properties, especially in the automobile industry to manufacture high performance and light weight diesel engine. However, the excellent mechanical properties of compacted graphite iron cause the tool life greatly shortened. In this research, the influence of tool structure on tool life is studied by simulation and experiment. Firstly, turning simulations for tools with different rake angles, clearance angles, and cutting edge radius were performed by the software Deform. Then orthogonal simulation was used to optimize the tool parameters. In addition, according to the tool parameters obtained in the simulation, a batch of tools with rake angles of 13°, 15°, and 19° were prepared, and their performances in turning compacted graphite cast iron were studied. The experiment results show that the life of the tool with 19° rake angle was 11.73% and 16.94% higher than that of the tool with 13° rake angle and 15° rake angle, respectively. And it has the minimum cutting force and lower wear value of the flank face. Our research is especially aimed at compacted graphite iron, which might have some function in improving the processing efficiency of compacted graphite iron. [ABSTRACT FROM AUTHOR]

The transverse bowing greatly affects the accuracy of the roll-forming asymmetric corrugated channels (ACC). In order to control this defect, the paper first elucidates its mechanism of the production. Then, the transverse bowing is explored by finite element method (FEM) using ABAQUS 2016 software and the effects of its forming parameters are analyzed. Also, a linear regression model is built using Minitab 19 software to evaluate their effects, of which standard values are measured by a Pareto chart. It is observed that the number of forming channels has the greatest effect, followed by the roll gap and bending angle, and the friction coefficient has the least. Finally, to decrease the transverse bowing defect (TBD), the dominant forming parameters are optimized according to the evaluation results and the operating conditions. And the results of simulation and optimization are verified by the experiments, respectively. This research shows that the TBD can be greatly controlled through the optimization of three dominant forming parameters including the roll gap, bending angle, and inter-station distance for given ACC. [ABSTRACT FROM AUTHOR]

This work proposes the development of a tool focused on monitoring simulation-based digital twins (DTs). Although it has been a popular approach in recent years, adopting DT simulation models for decision support in production systems implies some challenges, emphasizing the need for techniques to ensure the accreditation of the models over time. In this case, since the literature does not present alternatives for evaluating DTs models during their operation, this work proposes a tool based on the K-near neighbors (K-NN) classifier and the p control chart. In this way, it is possible to compare the behavior of the physical and virtual environments, monitoring the DT to guarantee its accreditation to support decisions. To assess the applicability of the proposed approach, we applied it to two real study objects with different characteristics, where the tool was able to evaluate the DTs simulation models. As a result, we observed that the proposed tool acted as a supplement to the DTs in order to make them more robust and reliable. Moreover, it was possible to monitor DTs with several evaluation variables in a simple way and with a friendly interface. [ABSTRACT FROM AUTHOR]

The medium carbon steel bars are widely used in automobile sector, mining, shipping, and forging industry. The use of SAE 1541 grade bars is quite common due to their affordability and adaptability. Basic production process of the metal bar involves heating the billet in reheating furnace up to 1200–1210 °C followed by passing it through a pair of grooved rolls in a rolling mill. The steel industries have been striving for productivity and better yield of hot rolled bar products. The roll separating force (RSF), driving torque (DT), and end crop length (ECL) are the important issues to be controlled for quality production, maximization of yield, minimization of rolled bar process scrap, safety of mill, and reduction in energy consumption. The response parameters depend on several process parameters – rolling speed, billet temperature, reduction ratio (strain), billet size (cross section area), roll diameter, etc. This paper presents a study on the effect of process parameters on these response parameters during rolling of SAE 1541 steel. Simulation of the rolling process has been attempted using FORGE® Nxt 1.1. The simulated results so obtained have been validated through experimental results obtained in a rolling mill, following statistical tests. Regression models showing relationship between the process parameters and the response parameters have been developed. Significant model-terms have been obtained using ANOVA. [ABSTRACT FROM AUTHOR]

Residual compressive stress can effectively improve fatigue the life of aerospace thin-walled parts. In this study, residual compressive stress control is taken as the target. Firstly, a surface residual stress prediction model is proposed, which considers both machining parameters and milling force heat. The model of the relationship between milling force, thermal load, and residual stress is established, which quantifies the effects of mechanical and thermal loads on the formation of residual compressive stresses. The results show that the feed rate of each tooth and the cutting-edge radius play an important role in the residual compressive stress of the milling surface. The prediction models of surface residual stress for thermal load, mechanical load, feed per tooth, and radius are established. Secondly, the ratio α of the feed rate per tooth fz to the cutting-edge radius r is quantified. When αxx = 0.42–0.65 and αyy = 0.36–0.7, the surface residual compressive stress in the x and y directions of the workpiece reaches the maximum value. Thus, the ratio of the feed rate per tooth fz to the cutting-edge radius r is optimized to control the mechanical and thermal load quantization. It realizes active control of residual compressive stress on the workpiece surface. [ABSTRACT FROM AUTHOR]

In the recoating process of the high-viscosity ceramic stereolithography, a large amount of ceramic paste is accumulated in front of the blade, and the fluidity of the high-viscosity ceramic paste is poor. The blade imposes forces on the solid part below, which deforms the fine structures of the part, affecting the accuracy of the part. In the actual printing process, slender rod parts appear T-shaped. This paper aims to investigate the causes of this phenomenon and to predict the deformation rate of a part. The understanding of the deformation phenomena can be used as theoretical guidance for dimensions or support sizes when modeling parts. A two-dimensional model has been developed to study high-viscosity materials with non-Newtonian fluid properties and slender rod parts, using the phase field method and a dynamic mesh to restore the recoating process. An experimental setup, which mimics the recoating process in the high-viscosity ceramic stereolithography process, has been used to verify the results of simulations. The results show the force exerted by the blade only affects the top portion of the slender rod part, and that the time of greatest impact on the deformation is the moment when the blade is reaching the top of the slender rod, generating a deformation rate that is cubic to the height of the slender rod. [ABSTRACT FROM AUTHOR]

In this paper, a surface roughness prediction model was proposed, which is used to predict the surface roughness of 3D ultrasonic vibration–assisted turning (3D-UVAT) driven by a single actuator. In addition to the kinematic roughness, material recovery, and plastic side flow, this model also considers the contribution of turning chatter. Based on experience, the roughness component equations affected by the chatter of turning system were put forward, and the topography of a finished surface was simulated. The ability of prediction model was evaluated through 3D-UVAT experiments. The experimental results show that the plastic side flow and the chatter of turning system on the finished surface were confirmed. Finally, the behavior of predicted roughness and measured roughness with different turning parameters were analyzed. The results show that the working ability of this predictive model is positive within the range of experimental conditions. [ABSTRACT FROM AUTHOR]

Electrochemical machining (ECM), an advanced manufacturing technology, is widely used in aero-engine blades machining. In traditional ECM, the electrolyte flows through the inter-electrode gap (IEG), generating hydrogen bubbles and heat, which affect the conductance and thus influence the machining quality. This paper focuses on the effect of bubble movement on the flow field and the machining quality of ECM. A novel vertical flow mode of electrolyte is proposed according to the bubbles dynamics analysis. Multi-physical fields simulations of blade ECM using vertical and horizontal flows were carried out. With an initial gas void fraction, flow rate, and temperature at the inlet of 0, 19.7 m/s, and 302.65 K, respectively, in both flow modes, the vertical flow reduces the gas void fraction, flow rate, and temperature at the outlet by 2.4%, 0.4 m/s, and 0.6 K, and increases the conductance by 0.47 S/m. Thus, the vertical flow of the electrolyte is beneficial in reducing the gas void fraction and controlling the temperature rise, while enhancing the conductance. Then, the corresponding experiments using a vertical flow were carried out. The maximum machining deviation ranges from 3.4 to 75.6 μm and surface roughness Ra < 0.35 μm. The machining quality is high and the variation observed in the experiments is consistent with the simulation results, the validity and correctness of the simulations are verified. Thus, the vertical flow mode proposed in this paper is appropriate, can be used for other complex structures in ECM. [ABSTRACT FROM AUTHOR]

Elliptical vibration-assisted cutting (EVC) is a method for rapidly creating ultra-precision free-form surfaces with micro groove features, which have a wide array of industrial applications such as drag reduction, self-cleaning action, optical tuning behavior, etc. The complicated fabrication process and limited shape and deep control of micro groove features by using EVC limit the applications of current EVC process in the fabrication of micro groove. To overcome these limitations and improve overall performance, a layered elliptical vibration-assisted cutting (LEVC) process is presented to fabricate deep micro groove with different shape. First, a detailed layered elliptical vibration-assisted cutting method is described, and a key step, the layered elliptical vibration-assisted tool path planning, is analyzed and established. Then, the machining stress under the proposed LEVC method and layered conventional cutting (LCC) process were simulated and compared through finite element analysis. The simulation results show that the LEVC process can generate the lower residual stress compared to the LCC process. To validate the machining performance of the proposed LEVC process, the machining experiments for two groups of micro grooves under the proposed LEVC process and LCC process are performed. The performance tests and comparison results between the generated micro grooves under the proposed LEVC method and LCC process indicate that the proposed LEVC method is effective for generating micro groove with the controllable shape and depth. The actual experiments show that the machining capability of the developed LEVC method for micro groove is satisfactory. [ABSTRACT FROM AUTHOR]

Functionally graded materials raise considerable interest in the biomedical research. In particular, gyroid structures are suitable for bone tissue engineering applications, allowing to emulate the porosity of the inner part of the bone. In this frame, the mechanical properties of 17–4 PH steel gyroids made by additive manufacturing have been investigated. Three design methods have been implemented, i.e., thickness graded, size graded, and uniform, to address the lack of knowledge in the area of stainless-steel scaffolds aiming at providing a map of the mechanical properties. Compressive mechanical properties absorbed energy and absorption efficiency have been found for the aforementioned design methods. Furthermore, defects and collapse behavior have been analyzed: imperfections have been detected in the thin-walled areas of the graded samples. Nevertheless, under given conditions, the graded samples have mechanical properties comparable to those of uniform ones, exhibiting a controlled layer-by-layer collapse mechanism and consequent weight reduction. The Gibson-Ashby models have been implemented, and the calibration coefficients have been compared with other research works. A FEM-based numerical model has been proposed to reproduce the mechanical properties of the mentioned structures finding critical issues in the representation of defects. In this frame, the resulting Gibson Ashby calibration coefficients are in good agreement with the literature and reveal the graded samples have a bending-dominating behavior sustaining larger strains than the uniform case, giving the ground for high energy absorption applications. Furthermore, the FEM analyses are in good agreement with the literature providing a reliable tool to further investigate the metal functionally graded gyroid field. [ABSTRACT FROM AUTHOR]

Functionally graded materials raise considerable interest in the biomedical research. In particular, gyroid structures are suitable for bone tissue engineering applications, allowing to emulate the porosity of the inner part of the bone. In this frame, the mechanical properties of 17–4 PH steel gyroids made by additive manufacturing have been investigated. Three design methods have been implemented, i.e., thickness graded, size graded, and uniform, to address the lack of knowledge in the area of stainless-steel scaffolds aiming at providing a map of the mechanical properties. Compressive mechanical properties absorbed energy and absorption efficiency have been found for the aforementioned design methods. Furthermore, defects and collapse behavior have been analyzed: imperfections have been detected in the thin-walled areas of the graded samples. Nevertheless, under given conditions, the graded samples have mechanical properties comparable to those of uniform ones, exhibiting a controlled layer-by-layer collapse mechanism and consequent weight reduction. The Gibson-Ashby models have been implemented, and the calibration coefficients have been compared with other research works. A FEM-based numerical model has been proposed to reproduce the mechanical properties of the mentioned structures finding critical issues in the representation of defects. In this frame, the resulting Gibson Ashby calibration coefficients are in good agreement with the literature and reveal the graded samples have a bending-dominating behavior sustaining larger strains than the uniform case, giving the ground for high energy absorption applications. Furthermore, the FEM analyses are in good agreement with the literature providing a reliable tool to further investigate the metal functionally graded gyroid field. [ABSTRACT FROM AUTHOR]

Water-based metalworking fluids are applied in the form of a liquid jet to flood the entire cutting zone and increase the tool life. The objective of this study is to investigate the effectiveness of flood cooling in reducing the tool chip interface temperatures during continuous cutting. An instrumented smart cutting tool with a thin film temperature sensor was fabricated to accurately measure the real-time cutting temperatures from 1.3 µm below the tool chip interface in orthogonal turning of AISI 4140 steel under dry and flood cooling conditions. The cutting process was simulated in Deform 2D with the Johnson–Cook material model to present the transient temperature distributions on the coated cutting insert. The heat flux into the cutting tool was also estimated analytically and then three-dimensional finite element heat transfer simulations were performed to determine the maximum convective heat transfer of the cutting fluid in steady state. The measurements with the embedded thermocouple showed that flood cooling with a water-based cutting fluid slightly lowers the tool chip interface temperature. Moreover, the chip color may not be a good characteristic indicator to evaluate the cutting temperature in machining of metals. It was also found that flood cooling becomes more effective at a distance of approximately 150 µm from the cutting edge where the chip does not contact the rake face of the cutting tool. [ABSTRACT FROM AUTHOR]

Due to demand of strong toughness of thin-walled tube, and good secondary forming properties and high-precision dimension, new plastic-forming method should be researched to achieve a complete filling, uniform deformation, and microstructural evolution during forming process. The deformation mechanisms of a new composite extrusion for thin-walled tube fabricated by direct extrusion and corrugated equal channel angular extrusion has been researched which is shorten as "TC-ECAE" in this paper. The plastic deformation behavior of magnesium billet during TC-ECAE process was researched by DEFORM™-3D software. Calculation parameters include material properties and process conditions have been taken into consideration. The predictions of strain distributions and damage distributions, and effective stresses distributions and flow velocities distributions have been explored. The results showed that TC-ECAE process is a magnesium alloy tube forming method suitable for industrial mass production. Serve plastic deformation of TC-ECAE would promote dynamic recrystallization which is magnesium alloy. [ABSTRACT FROM AUTHOR]

Electrochemical machining technology is adopted to solve the thorny problem of square deep hole machining. The distribution of the electrolyte flow field in the electrochemical machining gap of the deep square hole is simulated with the COMSOL simulation software based on the establishment of the gap electric field and the mathematical model of the gap electrolyte flow field. The simulation results show that the electrolyte flow field distribution in the machining gap is uneven and the electrolyte is not full. Therefore, the cathode structure in the corresponding machining gap area is optimized by the c o s θ method. The two-section square cone combination cathode with the bi-directional liquid supply is designed, and two groups of 16 added liquid holes with a diameter of 1.5 mm, a slope of 20° and an angle of 22.5° are adopted to improve the flow field distribution. After optimization, the extreme value of current density on the anode surface of the workpiece is reduced from 9.4 to 1.7 A/cm2, which significantly improves the uniformity of current density distribution. Finally, orthogonal experiments are conducted with different voltages, duty cycles, inlet flow rates and feed rates to obtain the experimental results of square hole size and surface roughness. The machining process parameters are selected by the grey correlation method: voltage 17 V, duty cycle 55%, an inlet flow rate of 20 m/s and feed rate 0.4 mm/min. The dimensions of the specimens meet the product requirements, enabling stable processing of square deep holes, significantly shortening the cathode design cycle and optimising the cathode structure. [ABSTRACT FROM AUTHOR]

Radio frequency identification (RFID) is a cost-effective method to support the Industrial Internet of Things (IIoT) and is an enabling technology for Industry 5.0. The use of RFID is particularly suited to IIoT as it does not require a line of sight for communication and can be retroactively affixed to non-smart items. However, RFID communication is affected by the properties of the material the tag is affixed to, specifically the material permittivity. Metal is commonly present in smart factory environments and supply chains and impedes RFID communication. A suitable tag design is required to accommodate these challenges and ensure resilience for Industry 5.0 applications. The research presented in this paper has assessed the communication performance of RFID antenna designs with and without metal present beneath the tag. The RFID tag designs that performed reliably in the simulation were manufactured, and their read range was tested on materials of varying relative permittivity and thickness to represent MP and NMP scenarios. The results have verified the robustness of "Cyber" to "Physical" designs and provide recommendations to support practitioner IIoT tag selection. [ABSTRACT FROM AUTHOR]

The autonomous vehicle storage and retrieval system (AVS/RS) significantly improves the responsiveness and throughput of the traditional automated storage and retrieval system (AS/RS) in regard to handling unit loads. The AVS/RS consists of multiple tiers connected to an elevator system and is equipped with at least two autonomous vehicles, that is, a shuttle and satellite. Other necessary equipment are the lifts and input/output buffer areas. This paper aims to present and apply an original hybrid analytical-simulative model for the design of a deep-lane and multisatellite AVS-RS by evaluating and controlling the system performance. This AVS-RS is equipped with multiple free and non-free satellites for each tier. As an original contribution, this study reviews the literature on AVS/RS according to the introduction of multiple features categorized into five homogeneous groups: (1) rack configuration, (2) vehicle kinematics and configuration, (3) dispatching rules, (4) modeling approach, and (5) validation. Two of the most critical issues in existing research studies are the random arrival time of storage and retrieval transactions and the random storage policy. The proposed modeling approach is data-driven and based on realistic assumptions, filling the gap between the literature and real applications. This hybrid model is applied to a case study of the beverage industry according to a what-if comparative and competitive multiscenario analysis. This data-driven assessment supports the decision-making process on the number of satellites for each tier, while simultaneously controlling the service and waiting times, system throughput, and vehicle utilization. The analysis based on the maximum system throughput estimation demonstrates that introducing more than two satellites does not increase the productivity of the system. [ABSTRACT FROM AUTHOR]

Wire electrical discharge machining (WEDM) is a non-conventional machining process renowned for precision in machining complex profiles, especially in high-strength and hard materials. This process also found other functions in machining cylindrical workpieces, known as wire electrical discharge turning (WEDT). The material removal mechanism of this process is based on electrical discharges, and evaluating the productivity of the continuous process to a great extent depends on the material removal of individual single discharges. In order to study the influence of rotational speed in material removal of erosion in cylindrical workpieces, theoretical and experimental studies of each single spark are necessary. This comprehensive study delves into the influence of rotational speed in WEDM processes applied to cylindrical workpieces. The research includes a series of single discharge experiments, and introduces a computational fluid dynamics (CFD) thermal model. The developed thermal model demonstrates the capability to predict the material removal rate of a single discharge with an error of 8.6% relative to experimental data. Furthermore, the investigation extends to continuous erosion studies, analyzing the material removal rate under varying rotational speeds. The overall material removal rate decreases 13% due to the declining material removal rate of each single discharge. Additionally, a removal efficiency parameter of erosion of cylindrical workpieces is introduced to provide an evaluation of the process and the influence of crater overlaps. The removal efficiency for various rotational speeds ranges between 22 and 24%, influenced by the proportion of normal discharges and the efficiency of crater overlaps. [ABSTRACT FROM AUTHOR]

Screw drill is one of the most widely used power drilling tools in the field of deep sea drilling because of its excellent performance such as low drilling speed, high torque, and strong overload capacity. However, it has the problems of complex internal structure and long processing stroke of screw drill stator. In this paper, the electrochemical machining (ECM) technology is used to solve the problem of internal spiral curved surface special-shaped deep hole machining. Firstly, the initial cathode structure with spirally increasing tooth surface of six machining teeth is designed, and the gas-liquid two-phase flow field model of the gap is established to simulate and analyze it. The simulation results show that the flow field distribution of the electrolyte in the machining gap is not uniform and the bubble concentration is high. Secondly, the initial cathode structure is optimized by adding different numbers of liquid-increasing grooves on the tooth surface of the machined tooth, and the gas-liquid two-phase flow field is simulated. The simulation results show that the cathode structure with four additional baths on each tooth surface results in a better overall flow of electrolyte in the machining gap, a flow rate of more than 3 m/s in the machining area, and a significant reduction in the concentration of electrolyte bubbles, with a reduced rate of 18.7% and a smaller distribution area for the highest bubble concentration, ensure the machining accuracy. Finally, the orthogonal experiment of 4 factors and 4 levels was designed, and the optimized processing parameters were obtained by gray correlation analysis method, that is, inlet pressure of 0.4 MPa, machining voltage of 11 V, duty cycle of 40%, and cathode feed rate of 0.9 mm/min, under which the deviation of the large end diameter of the deep special-shaped hole was 0.15 mm, the surface roughness of the inner wall of the hole was 0.487 μm. The data shows that this combination of processing parameters meets the production requirements of the product. The data shows that this combination of machining parameters meets the production requirements of the product. The COMSOL simulation method significantly shortens the research cycle and saves research costs. [ABSTRACT FROM AUTHOR]

Additive manufacturing is often used in rapid prototyping and manufacturing, allowing the creation of lighter, more complex designs that are difficult or too expensive to build using traditional manufacturing methods. This work considers the implementation of a novel digital twin ecosystem that can be used for testing, process monitoring, and remote management of an additive manufacturing–fused deposition modeling machine in a simulated virtual environment. The digital twin ecosystem is comprised of two approaches. One approach is data-driven by an open-source 3D printer web controller application that is used to capture its status and key parameters. The other approach is data-driven by externally mounted sensors to approximate the actual behavior of the 3D printer and achieve accurate synchronization between the physical and virtual 3D printers. We evaluate the sensor-data-driven approach against the web controller approach, which is considered to be the ground truth. We achieve near-real-time synchronization between the physical machine and its digital counterpart and have validated the digital twin in terms of position, temperature, and run duration. Our digital twin ecosystem is cost-efficient, reliable, replicable, and hence can be utilized to provide legacy equipment with digital twin capabilities, collect historical data, and generate analytics. [ABSTRACT FROM AUTHOR]

In many production applications, plants that produce multiple products with random demands share the required items among suppliers. The decision of how to allocate requests between suppliers to achieve the desired level of customer service is relevant to the efficiency of the production network. The literature highlighted how the long chain has the same level of performance as the full flexible network. This research proposes a decision model based on the game theory model to improve the performance of the production network. The model uses the Gale-Shapley algorithm with low computational complexity to share the demand among the suppliers. A simulation environment allows the evaluation of the proposed model in different conditions, and the model is compared to the dedicated, full flexibility, and long chain models. The numerical results show how the proposed model improves the efficiency of the production environment by keeping the number of connections with the supplier closer to the long chain model. [ABSTRACT FROM AUTHOR]

Thermoforming is a complex process with numerous parameters that potentially have an influence on the wall thickness distribution of the end product. Test benches do not allow for measuring all potentially relevant influences. Numerical simulations therefore have proven to be a useful tool in order to obtain deeper insight into the process and the mutual interactions between the input parameters. Forming air impact thermoforming can be thought of as an extension to common negative thermoforming that takes advantage of the flow inside the pressure chamber to obtain a favorable deformation behavior, ultimately leading to an improved final wall thickness distribution. The purposeful interaction between flow field and plastic sheet implies a significantly more complex physical system when approaching the process with modeling techniques. This paper describes the setup of a structural simulation model for thermoforming, that in an approximative manner includes effects of the flow field within the pressure box on the deforming plastic sheet. Special focus is laid on the implementation of counter-pressure due to the air trapped between sheet and mold. Validation simulations presented yield satisfactory results and thus show the high potential of simulations in modeling the complex interactions occurring in forming air impact thermoforming. [ABSTRACT FROM AUTHOR]

The development of advanced welding processes is of great significance, which is in order to adapt to the development of new materials and new welding environments. The discrepancies in the molten droplets, expressed by the characteristic parameters, are a reflection of the final welding quality. In recent years, more fundamental theories have been established, which have directed the optimization of the methods, through observation or numerical simulation. Innovations in methodology are made through thermal, mechanical, or hybrid effects. Based on the existing innovative methods, this paper predicts the future development directions for welding droplets. [ABSTRACT FROM AUTHOR]

Railway wheel manufacturing is a unique form of the hot forming process and consists of forging, rolling, and dishing operations. With the ever-improving technology, railway coaches and locomotives use wheels of various designs to cater to its growing need for speed and safety. Thus, it becomes imperative for a manufacturer of railway wheels to develop the capability of manufacturing railway wheels of a wide variety of designs to remain relevant in a competitive market. However, for developing any new wheel, the manufacturer needs to design new dies and rolls according to the new wheel design. Using a simulation model to predict possible outputs of railway wheel forming is essential for the design phase. Wheel rolling is one of the most complicated operations in railway wheel forming process. Railway wheel rolling is a particular type of shape rolling where a forged railway wheel is worked upon simultaneously by five rolls to give a specific shape. The present work attempts to develop a simulation model of the wheel rolling process. It proposes a mathematical model for determining roll movement parameters for producing wheels of any given dimension. The simulated results were compared with a rolled wheel from an industrial setup for a railway wheel manufacturing unit and found to be in good agreement based on the prediction of output geometry and load requirement. Thus, the developed simulation model based on FEM allows designers and shop managers to predict rolling outputs quickly with minimum cost implications. This model will help the designer eliminate costly trial productions required for stabilizing die and roll designs during the development of new railway wheels. Further, the simulation model can be beneficial for optimizing production parameters related to wheel rolling and understanding the effects of possible process deviations during production, thereby reducing rejections, energy consumption and improving the shop's overall productivity. The simulation was done using commercial DEFORM 3D finite element code. [ABSTRACT FROM AUTHOR]

In this paper, the laser shot peening (LSP) technology of H13 steel is studied to improve the friction and wear performance of shield machine hob. And to utilize the LSP experiment and simulation analysis, the influence of LSP parameters on the friction and wear performance of H13 steel after strengthening is studied. The numerical simulation study reveals the variation law of laser parameters on residual stress and stress layer depth. Study on friction and wear characteristics of H13 steel after LSP. The results show that the maximum residual stress of H13 steel is 911 MPa, and the hardness is 650.7 HV, when there are three times of black paint absorption and LSP. Compared with the raw material, the residual stress is increased by 125%, and the hardness is increased by 18%. And its friction coefficients and wear volume were relatively lower than other schemes. The average friction coefficient and wear volume were reduced by 10.8% and 57.2% respectively. [ABSTRACT FROM AUTHOR]