Evgeni Ivanov, Rumiana Kotsilkova, Vladimir Georgiev
et al.
This research presents a comprehensive investigation of PLA/PCL polymer blends using advanced rheological characterization, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and dynamic mechanical, thermal analysis (DMTA) to evaluate phase-separation behavior and functional properties. Polymer composites with various PLA/PCL ratios were fabricated via melt extrusion, a sustainable and scalable approach. The rheological studies revealed significant insights into the blends’ viscoelastic behavior, while SEM analyses provided detailed observations of microstructural phase separation. Thermal transitions and crystallization behaviors were evaluated through DSC, and the dynamic mechanical properties were examined via DMTA. The results confirmed that the tailored PLA/PCL blends exhibit properties suitable for advanced additive manufacturing (AM) and shape memory applications, merging flexibility and environmental sustainability. This study emphasizes the novelty of integrating multidisciplinary characterization methods to unravel the structure–property relationships in PLA/PCL systems. By addressing modern demands for eco-friendly, high-performance materials, this work establishes a foundation for the development of innovative polymer composites with potential applications in smart and responsive technologies.
The effects of tool wear on the accuracy of complex geometry in thin-sheet blanking are examined. Two illustrative examples are given. The first example considers the effect of tool wear when using a cutting die with a 5% clearance value. The second example considers the effect of tool wear when using a cutting die with a 3% clearance value. The volume loss and the improvement in punch-tip rounding of parts with complex geometries and sharp corners in thin steel sheets are obtained and compared. It is shown that punch wear changes according to the surface roughness of the cut piece and the burr height on sharp corners, radii, and flat surfaces. A strategy for calculating tool wear is also proposed. It was found that a die clearance of 5% provides much better results than a 3% clearance for soft sheets with a thickness of 0.50 mm in terms of minimizing tool wear and maximizing the clearance value.
Nehal Tarek, Abeer D. Algarni, Nancy A. El-Hefnawy
et al.
The emergence of Digital Twin (DT) technology over the past decade has introduced a transformative perspective to various research areas, notably the Job Shop Scheduling Problem (JSSP) in smart manufacturing. This paper proposes a novel algorithm to address the JSSP in industrial contexts, operating under different modes to minimize makespan and calculate energy consumption. The approach is grounded in a DT framework that leverages a knowledge graph to represent the assets of the manufacturing system. Two algorithms are designed to balance the time required to complete a list of jobs with the energy consumed by the machines in the factory, all while considering the delivery deadline of the final product. The first algorithm is a genetic algorithm (GA) that minimizes the makespan required to complete the job list for each mode of operation followed by a grey wolf optimization algorithm (GWO) to verify and enhance the results of the GA. The second algorithm uses the results of the first algorithm to calculate the running time and energy consumption for each machine in each production line, considering that the production lines of the factory vary in capacity and power, then computes the total energy consumption and presents the results to the decision maker via a dashboard. The dashboard displays, for each mode of operation, the makespan, total energy consumption, and the deadline for all the jobs. To validate the efficiency and accuracy, a case study of a Smart Poultry Feed Planet (SPFP) has been conducted.
Mauricio Leonel Paz González, Jorge Limon-Romero, Yolanda Baez-Lopez
et al.
Additive manufacturing via stereolithography (SLA) enables the fabrication of highly customized lattice structures, yet the interplay between geometry and graded density in defining mechanical behavior remains underexplored. This research investigates the mechanical behavior and failure mechanisms of cylindrical lattice structures considering uniform, linear, and quadratic density variations. Various configurations, including IsoTruss, face-centered cubic (FCC)-type cells, Kelvin structures, and Tet oct vertex centroid, were examined under a complete factorial design that allowed a thorough exploration of the interactions between lattice geometry and density variation. A 3D printer working with SLA was used to fabricate the models. For the analysis, a universal testing machine, following ASTM D638-22 Type I and ASTM D1621-16 standards, was used for tension and compression tests. For microstructural analysis and surface inspection, a scanning electron microscope and a digital microscope were used, respectively. Results indicate that the IsoTruss configuration with linear density excelled remarkably, achieving an impressive energy absorption of approximately 15 MJ/m<sup>3</sup> before a 44% strain, in addition to presenting the most outstanding mechanical properties, with a modulus of elasticity of 613.97 MPa, a yield stress of 22.646 MPa, and a maximum stress of 49.193 MPa. On the other hand, the FCC configuration exhibited the lowest properties, indicating lower stiffness and mechanical strength in compression, with an average modulus of elasticity of 156.42 MPa, a yield stress of 5.991 MPa, and the lowest maximum stress of 14.476 MPa. The failure modes, which vary significantly among configurations, demonstrate the substantial influence of the lattice structure and density distribution on structural integrity, ranging from localized bending in IsoTruss to spalling in FCC and shear patterns in Kelvin. This study emphasizes the importance of selecting fabrication parameters and structural design accurately. This not only optimizes the mechanical properties of additively manufactured parts but also provides essential insights for the development of new advanced materials. Overall, the study demonstrates that both lattice geometry and density distribution play a crucial role in determining the structural integrity of additively manufactured materials.
Óscar Barro, Felipe Arias-González, Ana Mejías
et al.
This study presents a novel approach in the laser cladding optimization field by integrating economic analysis with performance optimization. Despite extensive research on laser cladding technical performance, its economic evaluation—particularly when merged with productivity assessment—has scarcely received attention. This work addresses this gap by integrating an economic and productivity analysis with a standard performance evaluation through the employment of a multi-criteria optimization approach to balance technical and economic performances. To achieve this objective, a multi-parametric optimization via response surface methodology (RSM) and desirability function analysis has been developed. Results indicate that the employment of desirability analysis after RSM modeling is a valuable approach for laser cladding analysis, allowing the particular weighting of each result and providing the possibility of selecting processing parameters depending on the specific objective at any given time.
Philippe A. Passeraub, Quentin Allen, Elizabeth Clark
et al.
Current 3D printing processes for polymer material extrusion are limited in their accuracy in terms of dimension, form, and position. For precise results, post-processing is recommended, like with assembled parts such as pistons and cylinders wherein axial mobility is desired with low friction force and limited radial play. When no post-processing step of the printed parts is accomplished, the fit and the friction force behavior are strongly dependent on the process performances. This paper presents a study on parameters of significance and their effects on sliding and running fits as well as their friction forces for fused filament fabrication of such assemblies. A series of experiments were performed with multiple factors and levels, including the position or layout of printed objects, their layer thickness, the material used, the use of aligned or random seam, and the printer type. Piston–cylinder pairs were printed, measured, assembled, and tested using a tensile test frame. A mathematical model was developed to describe the oscillating friction force behavior observed. This study presents the feasibility and limitations of producing piston–cylinder assemblies with reduced play and friction when using appropriate conditions. It also provides recommendations to obtain and better control a desired running and sliding fit.
In incremental sheet forming (ISF), the geometrical accuracy is still a challenge that is only solved for specific applications. The underlying mechanisms of geometrical defects in ISF are very complex and still not fully understood. Nevertheless, the process understanding is constantly evolving. Recent work has shown, for example, how bending moments resulting from residual stresses affect geometric accuracy. It has become clear that resulting bending moments with an axis parallel to the main tool path direction are dominant. Based on that, the current paper investigates the hypothesis that linear and parallel tool paths lead to an unfavourable accumulation of residual bending moments along a common axis, and whether this accumulation effect can be reduced by wave-shaped tool paths. Thus, the described research investigates the influence of novel path strategies on the residual bending moments and the resulting geometrical deviations. The path strategies are based on wave-shaped path lines, whereas the curvature is within the sheet plane. The investigations focussed on a rectangular sheet that is clamped at its shortest edges and a part geometry-sensitive to springback. Experimental and numerical investigations show a significantly positive influence of some investigated path strategies on the geometric deviation, compared to a conventional path strategy.
Abstract Background Microsponges are one of the advanced drug delivery systems that facilitates precise and controlled release of active ingredients that are suitable for topical and oral use. These porous microspheres are typically sized between 5 and 300 μm, offer benefits including controlled release, stability, and minimized side effects. Manufacturing techniques like quasi-emulsion solvent diffusion and liquid–liquid suspension polymerization are usually employed to prepare microsponges, although various challenges arise from the use of potentially hazardous organic solvents. Main body Microsponges possess distinct traits such as extended drug release, formulation flexibility, and high drug loading capacity. Entrapment of drugs requires considerations of solubility, stability, and miscibility, while evaluation methods encompass production yield and particle size analysis. Their applications range from dermatological to biopharmaceutical delivery, with diverse products utilizing this technology. Ongoing innovations about microsponges are evident in patents concerning medical dressings and hyaluronic acid delivery systems. Conclusion Microsponges present a promising avenue in drug delivery, despite many challenges. Current review addresses on limitations and diverse products highlighting commercial viability. Patent activity signifies continued interest, suggesting significant potential for enhancing patient care.
Andrey A. Radionov, Olga I. Petukhova, Ivan N. Erdakov
et al.
The key priority of metallurgical industry development is expanding the range and improving the quality of bar products and their major component, steel wire. Continuous wire rod mills with multi-roll passes have been developed and implemented over the past decades. These include mills with four-roll passes with mutually perpendicular rolls. The specific feature of mills with complex passes is the impossibility of conduct and the direct measurement of the workpiece dimensions in several directions during rolling. The paper studies the development of a system for indirect control over complex section geometry by adjusting the interstand space tension with simultaneous compensation for changes in rolling forces. The paper contribution is the first justification of a technique for the control over the indirect rolled product section on mills with multi-roll passes based on theoretical and experimental research. Analytical and experimental dependencies between the metal pressure on the rolls and the semifinished rolled product temperature, rolling speed, and single drawing have been obtained for various steel grades. The impact of process factors on the rolled product section geometry when rolling in stands with four-roll passes has first been studied. The automated control system implementing the proposed technique has passed pilot tests on a continuous five-stand mill. The processes occurring in closed-loop speed and torque control systems under controlling and disturbing effects have been experimentally studied. Implementing the proposed algorithms indirectly confirmed the reduced impact of tension and pressure on the section geometry.
Noora A. Janahi, Christopher M. Durugbo, Odeh R. Al-Jayyousi
Networks in modern manufacturing are crucial for pooling resources, and eco-innovation enables manufacturers adopt sustainable production and environmentally friendly offerings. This article aims to explore network strategies for eco-innovation in manufacturing, from the viewpoints of industrial, academic, and governmental experts, i.e., using the triple helix model. Based on semi-structured interviews with 46 purposive sampled manufacturing experts, the article applies thematic analysis to identify categories of collaborative network and complex ecosystem strategies for eco-innovation. The analysis finds eight themes as strategies that centre on actions and commitment for stakeholder involvement, benchmarking support, capacity building, information protection, transition readiness, awareness campaigns, management audits, and plant designs. Theoretically, the findings imply network framings for the problem, potential, and priorities of eco-innovation in manufacturing, and practically the study suggests three critical factors for enhancing eco-innovation networks: (i) network platforms and forums, (ii) strategic alignment, and (iii) sustainability roadmaps. Using these network framings, the research contributes to current debates on eco-innovation strategies in cleaner production. The article concludes with discussions on the limitations and potential future research directions.
Systems engineering, Marketing. Distribution of products
Ricardo Espín, Byron Toalombo, Ángel Moyolema
et al.
This work aimed to optimize the operating processes through the Theory of Constraints (TOC) in a metal-mechanical company dedicated to manufacturing wood processing machines. The seven machines with permanent demand and all the operating processes were considered part of the sample. A process time and the available resources were evaluated, to quantify the utilization of the work centers. We indetified restrictions in the cutting and turning processes, with utilization percentages that prevented covering the average monthly demand. Based on the constraints and integer linear programming (ELP), the results show that the maximized production volume did not meet the average monthly demand. Therefore, the cutting process was technified, and the operators were redistributed, thus eliminating the restrictions. However, to optimize production according to the available resources, PLE was again applied. In this way, we optimized production covering the capacity required by the demand and increasing the gross profit by 12.91%.
Vicente F. Moritz, Gilberto S. N. Bezerra, Michael Hopkins Jnr
et al.
Injection moulding is a polymer processing method of choice for making plastic parts on industrial scale, but its traditional mould is made from tooling steel with time-consuming and costly production. Additive manufacturing technologies arise as an alternative for creating mould inserts at lower costs and shorter lead times. In this context, this study describes a series of stereolithography (SLA)-printed injection mould inserts fabricated from two photopolymer resins, utilised to mould standard tensile specimens of a commercial-grade polypropylene, aiming to evaluate effects on the polymer’s thermal and mechanical properties. Our results demonstrated that the glass fibre-filled resin inserts withstood more moulding cycles before failure, had superior mechanical properties, higher <i>T<sub>g</sub></i> and greater thermal conductivity. Calorimetric data revealed that PP thermal properties and degree of crystallinity were little affected, while mechanical testing suggests a significant effect in the elongation at break. Thus, these findings highlight the importance of adequate heat extraction during injection moulding and endorse further application of SLA mould inserts for the manufacturing of injection-moulded plastic parts in the case of prototypes or small batches, provided suitable cooling is made available, contributing to the feasibility and affordability of employing this approach for an industrial setting.
Don Pubudu Vishwana Joseph Jayakody, Tak Yu Lau, Ravindra Stephen Goonetilleke
et al.
In multi-axis fused deposition modeling (FDM) printing systems, support-free curved layer fabrication is realized by continuous transition of the printer nozzle orientation. However, the ability to print 3D models with complex geometric (e.g., high overhang) and topological (e.g., high genus) features is often restricted by various manufacturability constraints inherent to a curved layer design process. The crux in a multi-axis printing process planning pipeline is to design feasible curved layers and their tool paths that will satisfy both the support-free condition and other manufacturability constraints (e.g., collision-free). In this paper, we propose a volumetric curved layer decomposition method that strives to not only minimize (if not prevent) collision-inducing local shape features of layers, but also enable adaptive layer thickness to comply with a new volumetric error-based surface quality criterion. Our method computes an optimal Radial Basis Functions (RBF) field to modify the fabrication sequence field, from which, the iso-surface layers are extracted to design the corresponding multi-axis printing tool paths. A method to fine-tune variable nozzle orientations on each resulting curved layer is then proposed to overcome possible collisions in high-genus geometries. To validate the concept and exhibit its potential, several support-free fabrication experiments and comparisons with the conventional geodesic field-based slicing are presented, and the results give a preliminary confirmation of the feasibility and advantages of the proposed method.
Manufacturing companies in the textile and apparel field face stiff competition due to the globalization of trade between suppliers, producers and customers. To meet this challenge, they need to be efficient by adopting new lean manufacturing approaches and new analysis and management tools leading to more flexible and agile production and distribution processes. For the textile and apparel industry, where products’ life cycle is short due to fashion changes, a new integrated approach of production and distribution planning is needed. Based on linear programming techniques and integrating subcontracting activities, our approach takes into account the characteristics of demand, including its short life cycle, seasonality and fashion effect. For these reasons, a sequential approach is adopted, combining tactical and operational decision levels for production and distribution activities, in order to satisfy customer needs at lower cost by reacting quickly to changes and delivering on time. The deployed approach is structured according to the DMAIC lean tool. Validated on real instances, this approach proves its efficiency by achieving cost reduction when internal production capacity is adequately and efficiently planned.
Fused Filament Fabrication (FFF), which is one of the additive manufacturing methods, has recently found industrial usage areas and has become frequently used. Industries using this production method can be listed as automotive, machine manufacturing, aerospace, etc. While heat and environmental resistance are important factors for parts such as fixtures and apparatus manufactured with this method, mechanical properties are often at forefront. In many studies, the properties of the materials used in FFF under static load have been investigated by tests such as tensile, compression, and bending. However, studies on mechanical properties under impact loading remained at a relatively low level. It is clear that material behavior under impact loading is important, especially for polymer materials.
In this study, the impact resistance of notched Polylactic acid (PLA) samples produced by FFF method under different impact velocities were investigated. For this aim, a Charpy impact testing machine with low capacity (10J) was designed and manufactured, and the hammer was dropped from different heights and different velocity values were obtained. The instantaneous angle of the arm to which the hammer is attached was recorded by a gyro sensor and Arduino. Impact resistance values calculated depending on the impact speed were evaluated comparatively.
Technology, Motor vehicles. Aeronautics. Astronautics
Rafea A. M. Aljawadi, Desa Ahmad, Nazmi M. Nawi
et al.
This paper focuses on the in-field transporting machines currently used in oil palm plantations in Malaysia. It highlights the field conditions, the capacity of the machines and the time of completion of the transporting process which help to identify the determinants of the development of agricultural mechanization in Malaysian oil palm plantations. Understanding of the issues will help facilitate the elimination of weaknesses and defects prior to the manufacturing or modification stage. This will assist designers and manufacturers in the development and production of improved and more efficient field transportation equipment.
Carlos Gianpaul Rincón Ruiz, Marco Antonio Tejada Cardeña, Juan José Jiménez de Cisneros Fonfría
This article presents the design and analysis of an automatic shell broken machine of seeds of Metohuayo (“<i>Caryodendron orinocense</i> Karst”) with a production capacity of 50 kg/h, considering manufacturing and maintenance of local facilities. Metohuayo is the fruit of a tree that grows in various jungle areas of Perú, and the Metohuayo oil is very requested because of its nutritional properties. Starting with these specifications, the design was developed according to the systematic approach established by the VDI-2221 standard, with seven basic steps to analyze the optimum design. Once the definitive project was reached and the commercial components were selected, finite element simulations were performed to analyze the strength of the shell broken system and to evaluate the strength and the dynamic response of the structural support of the machine components. Additionally, complementary experimental studies were performed, such as the analysis of the required force to break the shell or the measurement of their dimensions.
Rohit Kshirsagar, Steve Jones, Jonathan Lawrence
et al.
Prediction of weld bead geometry is critical for any welding process, since several mechanical properties of the weldment depend on this. Researchers have used artificial neural networks (ANNs) to predict the bead geometry based on the input parameters for a welding process; however, the number of hidden layers used in these ANNs are limited to one due to the small amount of data usually available through experiments. This results in a reduction in the accuracy of prediction. Such ANNs are also incapable of capturing sudden changes in the input−output trends; for example, where a wide range of heat inputs results in flat crown (zero crown height), but any further reduction in the current sharply increases the crown height. In this study, it was found that above mentioned issues can be resolved on using a two-stage algorithm consisting of support vector machine (SVM) and an ANN. The two-stage SVM−ANN algorithm significantly improved the accuracy of prediction and could be used as a replacement for the multiple hidden layer ANN, without requiring additional data for training. The improvement in prediction was evident near regions of sudden changes in the input−output correlation and can lead to a better prediction of mechanical properties.
In the years 1928-1932, the Ukrainian SSR became a region whose industry became a priority for industrialization in accordance with the relevant plans of the federal government. However, the results of this process in Soviet Ukraine did not bring the expected results. Because of this factor, the role of Ukrainian industry in the union plan of industrialization has changed from avantgarde to ballast. One of the steps of the government of the USSR aimed at restoring the original idea was to creation of the plant automatic machines on the territory of the Ukrainian SSR. For the sake of his sake, he has done a great job in the saturation of the region and in the wilderness, and thus, the solution to part of theproblem of the lack of manufacturing capacity of Ukrainian machinery manufacturing plants, which arose due to the failure to comply with the first five-year plan. Meanwhile, the further development of the industrialization of the USSR showed the need to organize the production of automatic machine tools in the entire Soviet country. As a result, the construction of a suitable plant in Kiev has been revised in the direction of enlargement. However, not only was the number of organizational mistakes made at the organization stage of the plant not eliminated, but new ones were made. As a result, the plant of automatic machine tools in Kiev was introduced into the planned production volume with almost three years delay. For this reason, before the beginning of World War II, the Soviet machine industry branch did not receive the required amount of appropriate equipment and remained dependent on this product range from the more industrialized countries in the world.
Social history and conditions. Social problems. Social reform, Education