Manufacturing Characteristics Research Articles

Exploratory Studies of Mechanical Properties, Residual Stress, and Grain Evolution at the Local Regions near Pores in Additively Manufactured Metals.

Directed energy deposition (DED) is gaining widespread acceptance in various industrial applications since its unique manufacturing features allow the DED to print metallic parts with very complex geometries. However, DED inevitably generates a lot of internal pores which can limit the widespread applications of the DED technique. The current studies on DED porosity are mostly focused on analyzing pores' bulk-scale influences on mechanical properties and performances. Since DED pores have a micro-scale existence, with dimensions ranging from a few microns to several hundred microns, it is fundamental to explore the pores' influences on the micro-scale, including local mechanical properties, residual stress, and grains near pores. However, this important research direction has been neglected. The objective of this work is to fill the above gap in DED porosity research and acquire a fundamental understanding of the role of porosity on a microscopic scale. The authors used nanoindentation approaches to investigate internal pores' effects on mechanical properties and residual stress in local regions surrounding the pores. In addition, the grains near pores were observed through EBSD, and simulated with the Kinetic Monte Carlo model. The research findings can be provided for DED researchers and industrial practitioners as technical guidance. Most importantly, the research results can work as a good reference for tracing the source of bulk-scale mechanical performances and properties of DED parts with internal pores.

A heart-shaped bone artifact from Körtiktepe

Along with the emergence of sedentary life, the Pre-Pottery Neolithic (PPN) settlements brought revolutionary changes in production of material cultures as well as cultic and ritual activities, which are often argued to be associated with new waves of interactions between humans and their natural world. Körtiktepe of southeastern Turkey yielded by far the richest PPN assemblage in the world, standing among the very few earliest cultural and production centers which acted to be the predecessors of the development and spread of the Neolithic in West Asia. In this paper, we report a heart-shaped bone artifact which is one of the rarest finds in the extremely large cultural assemblage of Körtiktepe. The manufacture features indicate that the “heart-like” shape of this unique artifact was the product of intentional human activity. Overall archaeological context indicates its probable use as a bone pendant or amulet for the dead; providing the fact of its association with three early PPNA burials, many other ritual objects, and a large number of grave goods. Although difficult to argue for its association with the sense for “emotion”, “affection” or “love” in the present world, it is still significant that the unique specimen traces the symbolic presence and ritual use of the shape of a “heart” in West Asian prehistoric context back to the Early Pre-Pottery Neolithic of around 10000 cal BC.

FORMATION OF CONSUMER PROPERTIES OF ELASTIC LEATHER MATERIALS

For the effective use of leather material by the consumer, not only the physical and mechanical properties stipulated by the standard are taken into account, but also the hygienic and aesthetic ones, the role of which is determined by the technological features of manufacturing and operating conditions of the corresponding products. In this regard, there is a need for a comprehensive study of the consumer properties of leather materials, which determine their product quality and value for the consumer. The purpose of the study is to determine the technological features of the formation of consumer properties of elastic leather materials. At the same time, the following tasks were implemented: the filling and finish tanning of the leather semi-finished product of chrome tanning for the elastic material of the model and special purpose shoe upper; a coating is formed on the material for model shoes; consumer properties of leather material for model and special-purpose shoes are established. Research methods: consumer properties of leather materials were determined by a complex of physical-chemical, photographic and organoleptic methods. Research results. The influence of coating compositions based on polyurethane, polyacrylurethane and modified polyacrylate on the complex of physical-chemical and hygienic properties of leather material was investigated. It has been established that leathers with polyacrylic urethane finishing are characterized by high values of physical and mechanical and especially hygienic properties. Finishing of the frontside surface of the semi-finished product with the use of a polyacrylic urethane composition makes it possible to form a leather material of a wide range of colors with consumer properties that determine its intended use.

Identification of Barriers to Sustainable Manufacturing Implementation—The Perspective of Manufacturers of Parts and Components for Agricultural Transport

Sustainable manufacturing involves executing manufacturing processes in a way that follows the sustainable development principles, striving to combine economic, ecologic and social goals. The expected benefits of sustainable manufacturing are a lower cost and an improved environmental impact and well-being of employees. The main goal of the research was to identify barriers to the implementation of sustainable manufacturing principles. Achieving the main goal required the implementation of partial goals: (G1) designing the research tool based on the specific features of sustainable manufacturing identified based on the literature research; (G2) identifying of barriers that limit and/or prevent the implementation of sustainable manufacturing; and (G3) assessing the significance of individual factors limiting (preventing) implementation. The research was conducted in the agricultural transport sector and the subjects of the research were manufacturers of parts and subassemblies for agricultural transport. The ranking of limitations and barriers enables the definition of recommendations for companies willing to implement sustainable manufacturing concepts.

A Machine-Learning-Based Approach to Analyse the Feature Importance and Predict the Electrode Mass Loading of a Solid-State Battery

Solid-state batteries are currently developing into one of the most promising battery types for both the electrification of transport and for energy storage applications due to their high energy density and safe operating behaviour. The performance of solid-state batteries is largely determined by the manufacturing process, particularly in the production of electrodes. However, efficiently analysing the effects of key manufacturing features and predicting the mass loading of electrodes in the early stages of battery manufacturing remain a major challenge. In this study, a machine-learning-based approach is proposed to effectively analyse the importance of manufacturing features and accurately predict the mass loading of electrodes. Specifically, the importance of four key features during the manufacturing process of solid-state batteries is first quantified and analysed using a machine-learning-based method to analyse the importance of features. Then, four effective machine-learning-based regression methods, including decision tree, boosted decision tree, support vector regression and Gaussian process regression, are used to predict the mass loading of the electrodes in the mixing and coating stages. The comparative results show that the developed machine-learning-based approach is able to provide a satisfactory prediction of the electrode mass loading of a solid-state battery with 0.995 R2 while successfully quantifying the importance of four key features in the early manufacturing stages. Due to the advantages of its data-driven nature, the developed machine-learning-based approach can efficiently assist engineers in monitoring/predicting the electrode mass loading of solid-state batteries and analysing/quantifying the importance of manufacturing features of interest. This could benefit the production of solid-state batteries for further energy storage applications.

Optimal Design of Lower Limb Rehabilitation System Based on Parallel and Serial Mechanisms

This paper presents the structure and model of a hybrid modular structure of a robotic system for lower limb rehabilitation. It is made of two modules identical in structure, including an active 3-PRRR manipulator for moving the patient’s foot and a passive orthosis based on the RRR mechanism for supporting the lower limb. A mathematical model has been developed to describe the positions for the links of the active and passive mechanisms of two modules, as a function of the angles in the joints of the passive orthosis, considering constraints for attaching the active manipulators to the moving platform and their configurations. A method has been formulated for a parametric synthesis of the hybrid robotic system proposed with modular structure, taking into account the generated levels of parametric constraints depending on the ergonomic and manufacturability features. The proposed design is based on a criterion in the form of a convolution, including two components, one of which is based on minimizing unattainable points of the trajectory, considering the characteristics of anthropometric data, and the other is based on the compactness of the design. The results of the mathematical modeling are discussed as well as the analysis results towards a prototype validation.

Research on CNC programming and machining process based on CAD/CAM technology

Abstract Focusing on CNC process data, this paper provides an in-depth analysis, characterization and mining of macro machining processes by associating CAD and CAM models. The article introduces a Bayesian inference method to construct an association relationship between the manufacturing features of the query part and the macroscopic process of the manufactured part, which avoids the need for a direct similarity comparison between the geometry of the query part and the part to be manufactured. In addition, the study calculated the overall similarity between the query part and the CNC programming process data instances through the guidance of the process skeleton, thus realizing the precise evaluation from the CNC programming perspective. The algorithm for generating tool trajectories in multi-axis CNC programming is analyzed. By selecting representative surfaces and performing tool processing calculations, this study explores the process planning and tool parameter selection of usual parts of surfaces in multi-axis CNC programming machining. It optimizes the nonlinear error in tool trajectory processing by combining CAD/CAM technology. The results show that the optimized process proposed in this paper significantly improves the machining efficiency by 36.94%. In the cutting at tool corners, the maximum cutting force generated by the optimized machining process is only 190.3N, which is only 67.2% of the leading cutting force of the Cimatron process. In addition, when the engagement frequency is 780 Hz, the optimized process proposed in this paper has the smallest vibration amplitude, which is only 21.4% of the Cimatron strategy. Therefore, this study significantly improves the machining efficiency while ensuring the machining quality, which has important practical application value.

A new adsorptive 3D–printed sampling device for simultaneous determination of 63 urinary organic acids by LC–MS/MS

BackgroundThe detection and quantification of urinary metabolites play an important role in disease diagnosis. In most cases, urinary analyses are done with liquid urine samples, which must be quickly transported to the laboratory to avoid metabolites degradation that is associated with temperature fluctuations. Consequently, dried sampling devices have emerged to minimize analyte degradation. However, most commercial dried sampling devices are expensive, aggregate low volumes, and need better analytical sensitivity. Therefore, a new dry urine sampling device that is inexpensive, suitable for domestic sampling operation, and efficient for quantifying metabolites without requiring high–resolution instruments is proposed in the present study. ResultsThe newly designed dry urine sampling device was produced by 3D printing that efficiently determines 63 urinary organic acids using liquid chromatography coupled with mass spectrometry (LC–MS/MS). The system's efficiency was demonstrated with analytical figures of merit, such as precision, accuracy, and stability of analytes after the sampling and storing of ordinary urine samples. The limits of quantification ranged from 0.01 to 0.42 ng mL–1. Precision and accuracy tests showed relative standard deviations of less than 15 %. The urine stability in the sampling device was high within seven days without any significant degradation of the metabolites. The method was applied to the analysis of 10 human urine samples and compared to a conventional method without the use of the sampling device. The results showed no statistically significant differences, demonstrating the method's efficiency. SignificanceThe proposed 3–D printing device was developed with fast, low–cost manufacturing features and can be manufactured with different volumetric capacities, adaptable to the needs of each user. Furthermore, it is innovative because this is the first sampling device that is effective for the simultaneous storage and preservation of several important urinary metabolites. Thus, it is anticipated that its application would contribute significantly to the identification of metabolic disorders.

Development of a deviation package method for low-cost robust optimization in compressor blade design

Manufacture variations can greatly increase the performance variability of compressor blades. Current robust design optimization methods have a critical role in reducing the adverse impact of the variations, but can be affected by errors if the assumptions of the deviation models and distribution parameters are inaccurate. A new approach for robust design optimization without the employment of the deviation models is proposed. The deviation package method and the interval estimation method are exploited in this new approach. Simultaneously, a stratified strategy is used to reduce the computational cost and assure the optimization accuracy. The test case employed for this study is a typical transonic compressor blade profile, which resembles most of the manufacture features of modern compressor blades. A set of 96 newly manufactured blades was measured using a coordinate measurement machine to obtain the manufacture variations and produce a deviation package. The optimization results show that the scatter of the aerodynamic performance for the optimal robust design is 20% less than the baseline value. By comparing the optimization results obtained from the deviation package method with those obtained from widely-used methods employing the deviation model, the efficiency and accuracy of the deviation package method are demonstrated. Finally, the physical mechanisms that control the robustness of different designs were further investigated, and some statistical laws of robust design were extracted.

Composite Forming Technology for Braiding Grid-Enhanced Structures and Design of a New Weaving Mechanism

Three-dimensional weaving structures have high strength and resistance to interlayer shear due to their integrated manufacturing features. The traditional weaving equipment is generally huge and is not effective for weaving small-sized products. Therefore, this paper proposes a new composite forming technology and weaving mechanism based on grid-enhanced structures to braid small-sized preforms, combining the continuous fiber printing technology, the rope drive technology and the 3D weaving technology. This paper adopted the screw theory for forward and inverse kinematic analysis of the weaving mechanism and applied software Adams2020 for trajectory simulation analysis. The theoretical calculation results were basically consistent with the simulation results, which verified the rationality and feasibility of the designed weaving mechanism in small, enhanced grids.

Spirulina and its residual biomass as alternative sustainable ingredients: impact on the rheological and nutritional features of wheat bread manufacture

Introduction: Following consumers’ demand for healthier alternatives, Spirulina biomass has been included as a functional ingredient in different types of food as a sustainable alternative to improve physicochemical characteristics and nutritional aspects in the diet. This study aimed to explore the use of Spirulina biomass (SB) and residual biomass (RB) obtained after C-phycocyanin (C-PC) extraction in the production of wheat bread (WB).Methods: The dough rheology, texture, color, nutritional aspects, and bioaccessibility of the different manufactured bread samples were accessed to achieve this goal.Results and Discussion: This is the first research to exploit RB. It was possible to replace 3% of wheat flour for SB or RB in bread-making; this substitution did not impact the rheological characteristics of the dough, even though the pH increased with the addition of SB or RB (5.63 and 5.70, respectively). SB and RB addition improved bread volume and enhanced the nutritional profile, increasing the antioxidant capacity (DPPH and FRAP) compared to WB. Heavy metals (Ni, Cd, and Pb) were not found in any of the samples (<0.2 mg/100 g). The in vitro protein digestibility in bread was better than in SB and RB raw materials, which indicates that bread manufacturing may contribute to improving protein digestibility. In addition, SB needs greater appreciation for sustainable food practices worldwide and in Brazilian exploration, requiring management strategies with industry and society working together. Further studies are necessary, focusing on acceptability to understand the viability of these ingredients to target consumers’ preferences.

Surface Characterisation and Comparison of Polymeric Additive Manufacturing Features for an XCT Test Object

Additive manufacturing (AM) has experimented a huge development in recent years, improving the physical properties of parts produced by these technologies to the level of being capable of fabricating end-use functional products. High performance metals are widely used and studied; however, the reduction in material costs of polymers and their acceptable properties makes them suitable for common AM purposes. The intrinsic surface roughness of AM, as a consequence of the layer-by-layer technology, remains a challenge and its characterisation is necessary for quality control. X-Ray computed tomography (XCT), as a newly adapted evaluation technology for industrial applications, sets an opportunity for the dimensional measurement of AM parts, due to its capability of characterising the complex geometries that is possible to create with this manufacturing technologies. In this paper, a first approach to a surface characterisation of polymeric AM parts is presented. Several individual objects have been designed and manufactured using various polymeric AM technologies with different manufacturing principles (FDM, Polyjet, SLS) to build ramps with a range of surface roughness created by two main parameters (angle of inclination and layer thickness). Measurements have been carried out by an optical device (focal variation microscope, FVM), and a comparison with theoretical roughness values calculated following predictive models has been made, with the objective of analysing the behaviour of each surface. Results show that the influence of the angle of inclination is higher than the influence of layer thickness; post-processing, also, affects to the trueness of the real roughness comparing to the predicted one obtaining more unpredictable results.

Geometric feature extraction in manufacturing based on a knowledge graph

In times of global crises, the resilience of production chains is becoming increasingly important. If a supply chain is interrupted, a cost-effective solution must be established quickly. In the context of Industry 4.0, the concept of smart manufacturing offers a solution for fast and automated decision-making in production planning. The core idea of smart manufacturing is the digitalization of the product life cycle and the linking of individual phases of this cycle. Computer Aided Process Planning (CAPP) plays an important role as the connecting element between design and manufacturing. An important prerequisite for CAPP is the automated analysis of 3D models of components. The aim of this work is the development of an automatic feature recognition (AFR) -method to recognize geometric manufacturing features and their properties from 3D-models and then store them in a knowledge base. In that way, the result of the design can be automatically analysed and compared with manufacturing information afterwards in order to achieve an automated process planning. Geometric and topological information of a 3D model (STEP-AP242 format) generated by CAD systems is extracted by a Python-script developed and stored in an ontology-based knowledge base. The extracted product data is analysed using a Python-script to identify manufacturing features. To provide a comprehensive extensibility of the model, geometric features are defined according to a layered and hierarchical structure.

Three‐dimensional polymer composite flow simulation and associated fiber orientation prediction for large area extrusion deposition additive manufacturing

AbstractMaterial flow and associated fiber orientation are among the most important features in Large Area extrusion deposition Additive Manufacturing (LAAM) of short fiber‐filled composites. Endeavors have been done in 2D flow models, where significant knowledge is achieved in explaining the material anisotropy of the deposited composite parts. Nevertheless, 2D flow models are limited by a couple of assumptions that lose significant characters of the deposition flow. This study is one of the first few that employ a 3D flow model which focuses on the quasi‐steady state of the polymer composite melt flow within the nozzle and the subsequent 90‐degree turning deposition onto the material substrate. The material flow is assumed as a highly viscous Newtonian flow. The fiber orientation is evaluated using the advanced pARD‐RSC fiber orientation tensor evaluation model, via the one‐way weakly‐coupled flow/orientation analysis formulation. Computed results show the fiber orientation state on the entire cross‐section of a deposited bead, which yields a clear view of how the material anisotropy is affected by the locally varied fiber orientation. The 3D‐flow prediction proves that the transverse directional fiber alignments are in high degree of similarity as compared to the over‐predicted results from the simplified 2D planar flows. In addition, the 3D‐model results exhibit a more favorable agreement with the reported experimental data than that yielded by the conventional 2D models.

Experimental and numerical study on a new noise reduction design for a small axial fan

The broadband noise of an axial fan is highly related to the vortex shedding at the blade trailing edge and the secondary flow at the blade tip. Herein, a circular arc design is proposed to modify the shape of blade tip and trailing edge together with the features of simple structure and easy manufacture. The experimental and numerical studies were conducted to investigate the effect of circular arc design on the aerodynamic and acoustic characteristics of a small cooling axial fan through the experimental method of the semi-anechoic chamber and LES simulation combined with FW-H. The tested and calculated results show that the SPE of the fan with R7 circular trailing edge can be improved for the entire flow rate range. And the SPC is decreaed as the increasing of arc radius. For the fan with R7, the SPE can be increased by 2.1% and the SPC is decreased by 4.8% at the designed flow rate. In terms of acoustic characteristics, the modified impeller can suppress the broadband noise in the range of 1000 ∼ 3000 Hz, and this suppression can be improved with the growth of flow rate. The R7 design shows the best noise reduction performance, with 2.4 dB reduction over the prototype.

STATE INDUSTRY POLICY IN THE FIELD OF IMPORT SUBSTITUTION OF INFORMATION PRODUCTS AT AVIATION INDUSTRY ENTERPRISES

In the research article, the authors consider the main proposals for the implementation of the state sectoral policy in the field of import substitution of information technologies and systems (ITiS) at high-tech enterprises in the aircraft industry in modern innovative and financial conditions. For this, the main features of aircraft manufacturing enterprises that are part of the United Aircraft Corporation (UAC) were considered from the point of view of automating their typical business processes, where the implementation of the state industry policy in the field of import substitution is supposed to be implemented. The authors carried out an organizational and economic analysis of the Russian ITiS market, as well as formulated the main measures and procedures that should be implemented at high-tech aircraft manufacturing enterprises within the framework of the state sectoral policy in the field of import substitution. The article also considers an example of the implementation of the Russian information system in the development of a project for the automation of production accounting at the head enterprise of the UAC as part of the implementation of this policy.
 Purpose – determination of methods and techniques for automating typical business processes of aircraft manufacturing enterprises through the use of domestic information technologies and systems as part of the implementation of the state industry policy in the field of import substitution of information and communication technologies.
 Methodology. The article used methods of empirical research, information-logical and expert methods, as well as methods of analogy and comparison.
 Results. The most informative parameters were obtained, showing the economic feasibility and effectiveness of the introduction of domestic information technologies and systems at aircraft manufacturing enterprises as part of the implementation of the state sectoral policy in the field of import substitution of information and communication technologies.
 Practical implications. The obtained results should be applied not only at the enterprises of the UAC aircraft industry, but also at the enterprises of other high-tech industries of the State Corporation Rostec, where automation of the main standard business processes is an important component of their further development.

Spatially confined lignin melting flow enabled a strong, tough, and light-manageable silastic-nanopaper for flexible and stretchable electronics

Flexible electronics based on cellulose paper have attracted a new surge of interest over the past decades due to their eco-sustainable, renewable, and scalable roll-to-roll manufacturing features. However, the application of traditional paper in flexible electronics is hindered by its inferior stability against heat and water, weak mechanical strength, and its large surface roughness and porosity usually result in a poor circuit continuity. Herein, the hot-pressing induced space-confined flow was adopted to drive the melted lignin spread along the cellulose nanofiber (CNF) chains, then the silastic was further integrated into the lignin uniformly coated CNF membrane to construct a silastic-nanopaper substrate for flexible and stretchable electronics. Attributed to the lignin-induced interfacial molecular bridge, the enhanced hydrogen bonding between lignin and CNF, and the adhesive interaction between lignin and silastic, the developed silastic-nanopaper demonstrates an impressive tensile strength (∼380 MPa), toughness (52.75 MJ/m3), and elongation (16.2 %), much superior to the pure CNF (200 MPa, 4.12 MJ/m3, and 3.0 %, respectively). The silastic-nanopaper also shows a low surface roughness (∼3 nm), high wet strength (>350 MPa) and thermal stability (with the maximum decomposition temperature of 480 °C), good UV-blocking capacity, and tunable transmittance haze. The electronic sensor fabricated based on such silastic-nanopaper exhibits a highly sensitive and reliable piezoresistive response to persistent stretching and twisting. The strategy of combining the advantages of lignocellulose and PDMS paves the way for the cost-effective, easy-to-operate manufacturing of electronic substrates.

Data-driven prediction of keyhole features in metal additive manufacturing based on physics-based simulation

Data-driven prediction of keyhole features in metal additive manufacturing based on physics-based simulation

Progress in grinding performance by additive manufacturing of grinding wheels integrated with internal venturi cooling channels and surface slots

Among the most promising features of additive manufacturing are tool or form-free manufacturing and the ability to create intricate geometries that are difficult or even impossible to fabricate with traditional methods. These advantages can be employed to produce enhanced grinding tools. Efficient coolant fluid delivery into the cutting zone of the grinding operation has been a challenging problem since high frictional contact in the arc zone deteriorates the resin bond and lessens the grinding performance. This research study was dedicated to assessing the influence of internal cooling along with surface structures on the grinding performance of resin-bonded grinding wheels fabricated via additive manufacturing. This research introduced a novel structure that benefits from internal venturi shape cooling channels to provide exceptional fluid velocity in the tool and workpiece interaction zone. The grinding wheels have been produced employing vat photopolymerization. Grinding experiments with and without internal cooling were conducted on an aluminium plate to study the impact of introduced structures on the main aspects of grinding performance, such as cutting forces, surface roughness, tool wear, and dimensional accuracy. Two different grinding scenarios comprising shallow (10 μm depth of cut) and deep grinding (100 μm depth of cut) were carried out to reveal the influence of the material removal rate on the grinding experiments. The measured grinding forces revealed that integrating internal cooling channels and surface slots in a grinding tool could significantly reduce the grinding forces, which was more pronounced in the case of using venturi channels. Measured tool wear and dimensional accuracy together with calculated grinding ratio revealed that using cooling channels could participate in a notable increase in tool life and material removal ability, especially for venturi channels, due to improved cutting conditions, by which higher dimensional accuracy was obtained as well for the ground parts. Besides, it was discovered that the cooling channels could improve the surface quality of the ground part, which was less noticeable with the venturi channel grinding wheel. Furthermore, the optical and confocal microscopy detection confirmed that internal cooling channels could reduce chip loading on the grinding wheel surface, decrease the required number of dressing intervals, and cause effective promotion of tool life.

Automated Determination of Grain Features for Wire Arc Additive Manufacturing

The morphology and size of the grains of the additively manufactured (AM) parts affect the mechanical properties and performance. The present research aimed to analyze the microstructure of AM parts, particularly the grain features, using image processing techniques. AMed aluminum components were fabricated using wire arc additive manufacturing based on cold metal transfer. The AA 5183 tensile samples fabricated using WAAM-CMT showed ductile behavior and the presence of the Lüder bands. Metallographic sections were prepared, and fine equiaxed grain was observed. An automatic image evaluation program for determining the specified grain features was developed. The grain features, including size, area, perimeter, and sphericity, were quantified, and the obtained results were verified, indicating a satisfactory agreement with those obtained from manual measurement. The output of the image processing technique clearly proved that the MATLAB program, as an affordable and swift approach (~ 4.8 s), can be used successfully to determine the microstructural properties. The image processing techniques could significantly improve the reliability and analysis of the microstructure, which would lead to the possibility of characterizing the microstructure in a broader range and having more details, and saving time and cost.