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This article explores the effect of cryogenic temperatures on the properties of cobalt alloys, specifically Stellite 6 and Stellite 12. These alloys are commonly used in applications that require resistance to me-chanical, thermal, and chemical wear. In this study, the focus is on the valve seats for internal combus-tion engines, which are made from cobalt alloys and undergo a freezing process before assembly into the cylinder head. The purpose of freezing is to reduce the diameter of valve seats, making them easier to fit into the cylinder head. However, the length of time spent in freezing can significantly affect the hardness and tribological characteristics of the material.

The present work was aimed at studying the effect of a “Slab/Sheet” thickness ratio (SSTR) on the microstructure and mechanical properties of API 5L X70 steel sheets intended for heavy-wall oil/gas pipelines. The 25 mm-thick and 40 mm-thick steel sheets were rolled from the cast slabs of different thicknesses (250 mm and 300 mm) and their mechanical properties were compared. The sheets were subjected to thermo-mechanical controlled processing followed by accelerating cooling, resulting in the structure of quasi-polygonal/acicular ferrite with minor amounts of granular pearlite and martensite-austenite constituents. Increasing the cast slab thickness significantly improved the ductility and low-temperature impact toughness of steel sheets regardless of their thickness. Specifically, a total elongation increased by 3-6 points (up to 26-28 %); an absorbed impact energy (tested at –20 °C) – in 1.5-1.8 times (up to 300-370 J); the DWTT shear area (at –20 °C) – in 1.6-2.1 times (up to 81-91.7 %). The properties advancement under SSTR increase was associated with an additional refinement of ferrite grains and better homogenization of cast structure under deeper hot deformation.

Manufacturing inaccuracies in vehicle suspension systems inevitably lead to uncertainties in the parameters of their structural components. Simultaneously, the road excitation impacting nonlinear vehicle systems exhibits pronounced randomness and time-variant characteristics. Consequently, it is crucial to conduct a stochastic dynamics analysis on nonlinear suspension systems, taking into account these uncertain factors. In this paper, a seven-degree-of-freedom (7-DOF) nonlinear suspension system dynamics model has been established. The stochastic process of road irregularities is simulated using the harmonic superposition method. Moreover, based on the direct probability density integral method, the stochastic dynamic equations of the nonlinear suspension system and their corresponding solution strategies have been developed and explored. Through MATLAB, the time-varying probability density function of the vibration response for a nonlinear vehicle suspension system was calculated under the combined effects of stochastic road irregularity excitation and random coupling of system structural parameters. Additionally, analyses were conducted on how different coefficients of variation and the intensity of nonlinearity in the suspension system influence the probability density of the output body displacement of the nonlinear vehicle suspension system. The research outcomes demonstrate that the direct probability density integral method offers superior efficiency and accuracy when computing nonlinear vehicle suspension systems. Furthermore, altering the coefficients of variation for various system parameters reveals that as these coefficients increase, the disparity in the probability density of body displacement becomes more pronounced, leading to more intense vehicle vibrations. Under soft nonlinear conditions with lower suspension spring stiffness, the probability density function of body displacement shifts slightly to the right with minimal change. However, under strong nonlinear conditions, body displacement significantly increases, resulting in diminished vibration isolation capabilities of the suspension system. This leads to severe jolts and a noticeable decline in ride comfort during vehicle operation.

The article deals with the evaluation of the amount of wear of the base material and selected hardfac-ing materials intended for tools for wood processing in forestry after a test of resistance to abrasive wear in laboratory conditions. The values of average weight loss Wh[g] and relative resistance to abrasive wear Ψh[-] were determined by calculation. The topography of the surface after the track of the rubber disc and the abrasive of the testing device was evaluated with a confocal microscope. The depth of the disc track Pt[μm;mm] was also evaluated with a confocal microscope. The state of the samples surface after the test, as well as the overall structure and mixing of the hardwearing material with the base material was evaluated by light microscopy. A touch roughness meter was used to de-termine the profile of the track surface after the test. Based on the results, we can recommend certain hardfacing materials for practice. Their abrasive resistance and thus also the loss of material during the work load could ensure a longer service life of the tool.

The purpose of this paper is to study an application of the 35NCD 16 steel by a model generalizing the isotropic and kinematic strain hardening laws. The model in question is represented by a field of strain hardening moduli corresponding to the introduction of the configuration of the flow surfaces. Each flow surface is characterized by its constant elastoplastic modulus, its normal unit vector, its radius and its center coordinates. For cases of uniaxial or multiaxial (complex) loading, in particular for cases of cyclic loading or unloading, the instantaneous configuration can be determined by the position and dimensions of the flow surfaces, determining the strain increment for each strain incre-ment.

Motor rehabilitation contributes to neural remodeling in individuals with motor disabilities, which is crucial for their recovery of motor ability. In addressing the No. of human-machine coupling and synergistic motion characteristics in motor rehabilitation, this study analyzes the collaborative motion characteristics of each joint in the lower limbs. A virtual human-machine coupling system is proposed, and the driving functions of the human-machine coupling system are designed. By utilizing ADAMS motion simulation software, the motion characteristics of the human-machine system are analyzed, and the variation patterns of motion parameters at key positions are obtained. Based on this, the system's synergy is analyzed and experimentally validated from the perspectives of gait, motion speed, and joint motion angles. The experimental results demonstrate that the hip and knee joint angles of the exoskeleton robot exhibit a motion pattern highly consistent with that of the human body, with an angle error of less than 3°,indicating excellent synergy.

This article presents the development and validation of SBRI (Small Business Digital Maturity Assessment and Road to Industry 4.0), an innovative methodology for assessing digital maturity and supporting digital transformation specifically designed for small manufacturing enterprises in the context of Industry 4.0. Unlike existing models, which are often too complex or unsuitable for smaller organizations, SBRI considers the unique characteristics and constraints of small businesses. The methodology includes five key dimensions: Strategy, Technology, Process, People, and Organization, elaborated into 25 subdimensions with specific maturity criteria and indicators. The SBRI includes a structured roadmap for digital transformation through a proposed digital maturity continuous improvement cycle. An empirical study involving 23 small manufacturing enterprises in the Czech Republic has demonstrated the validity and practical applicability of the methodology. The results showed an average level of enterprise digital maturity of 0.9 on a scale of 0 – 4. These findings suggest that small businesses are just at the beginning of their digital transformation journey. Therefore, the SBRI methodology represents a valuable tool for navigating small businesses through their digital transformation journey, contributing to academic discourse and practical application of Industry 4.0 principles in the small business segment.

The submitted paper deals with biotribological contact in total knee arthroplasty. The goal was to evaluate the influence of the metal component production technology on tribological parameters in defined environments. The reference sample was a standard available test ball made of the subject material, used in testing tribological properties by the "Ball on Pin" method. The preparation of the experiment consisted in the production of test disks from UHMWPE material and the production of a metal test component with a spherical surface. The condition of the experiment and the basis of this contribution is to compare the properties of conventionally produced metal material against 3D printing. Using the SLM method, a sample with a semi-spherical surface on a cylindrical shank was produced, which was subsequently ground and polished to reflect the characteristics of the standard supplied test ball. The last step was the production of a suitable fixture in order to fit the sample into the tribometer. The so-called dry friction of the heterogeneous Ti6Al4V–UHMWPE pair and the friction in a biological lubricating environment represented by bovine serum were evaluated. The evaluation of the contact surfaces took place using a profilometer and an electron microscope. The coefficient of friction was determined directly from the test device - tribometer.

Based on the high hardness, poor thermal conductivity, and easy detachment of graphite in cast iron materials. Traditional rough machining inserts cannot achieve good machining surface quality, while the use of precision machining inserts results in rapid tool wear due to excessively sharp rake angles, limiting feed rates and reducing machining efficiency. In order to solve these problems, this paper proposes a method of cutting cast iron with coarse and wiper insert mixed cutting tools, aiming to improve the surface quality of machining and enhance machining efficiency. By studying the mecha-nism and cutting experiments of the wiper inserts, it was found that it improved the surface quality of cast iron and analyzed the reasons for tool wear. By controlling the integrity of the precision ma-chined surface of cast iron, the aim is to establish the basic theory and key technologies for the pre-cise and efficient manufacturing of high hardness materials. Improve the surface quality of cast iron processing, extend tool life, and improve processing efficiency.

Gears and toothed parts are significant components in power transmission systems. These parts usu-ally manufactured by traditional methods such as machining by milling or forming by rotary forging. In this study, the forming of solid gears or toothed parts using a forging process that combines rotary forging and ballizing technique. The specimens were placed inside the die with excessive volume to fill the toothed part in the die. The forming tool applies pressure to the specimen while rotating it together with the die by the lathe machine chuck, while the tool advances continuously in the direc-tion of the die. This reduces height of the specimen and increases its diameter, causing metal flow to fill die cavity teeth and form the gear or toothed part required for production. Two sets of experi-ments were performed. In the first set, optimization for the appropriate volume of four different sizes of dies and four forming tools was conducted. While in the second set, the effects of forming process variables on the forming load and tooth filling percentage was studied. The results showed that the best tooth filling ratio happened with specimens size of 1.2 to 1.4 times the volume size of the desired tooth for filling. The results also revealed that the forming speed, die size, and forming tool diameter affect the filling ratio and forming load.

The conventional method for measuring propeller geometric parameters involves utilizing specialized equipment or 3D measuring devices. Currently, specific propeller geometry parameters can be as-sessed by employing virtual measurements performed on a virtual propeller model generated using reverse engineering methods. This paper introduces a novel approach to constructing 3D models of small fishing boat propellers using photogrammetry and reverse engineering techniques. In this method, the propeller is captured through photographs taken with a smartphone camera employing special techniques. Subsequently, these images are processed using Agisoft Metashape to generate a mesh model, from which a precise photogrammetric model of the propeller is developed using CATIA. By comparing the photogrammetric model with the scanned model in GOM Inspect, and evaluating the measurement outcomes of blade radius and pitch on virtual and physical models, it is possible to ascertain that the photogrammetric model exhibits exceptional accuracy. Consequently, the photogrammetric model can be effectively utilized for the measurement of propeller geometric parameters.

The aim of this article is to approach the measurement of forces and pressures of collaborative robots. In the article, research will be carried out on measuring the forces and pressures of a collaborative robot before putting it into real application. Force and pressure values will be measured using appropriate measuring devices. The measured results will be compared with the ISO/TS 15066:2016 technical specifi-cation and subsequently evaluated.

This article deals with the comparison of the wear of indexable CNMG carbide inserts from two dif-ferent manufacturers when turning austenitic stainless steel 1.4404, which is not intended as the pri-mary material to be machined from the point of view of the tested inserts. The main goal was to demonstrate the different course of wear by testing inserts of the same type according to ISO 6987 showing the connection between the design and processing of the inserts in connection with the se-lected cutting parameters. The monitored type of wear was the main flank wear VBmax, depending on the length of the machining time. Optical and electron microscopes were used to analyze the flank wear. According to the assumption, it was found that the layout of the cutting edge geometry and coating layers has a noticeable effect on the degree of wear of the evaluated cutting inserts. At the same time, it was found that the tested indexable inserts achieved very good service life values de-spite the fact that the tested material does not belong to the primary use group. Evaluation of cutting tool wear has a significant economic potential for manufacturing companies seeking to minimize costs by trying to use as many universal cutting tools as possible or looking for opportunities to ex-pand the applications of already used cutting tools.

Precision mirror mould CNC machining is a technology of great importance in industrial manufacturing. Precision mirror moulds are usually used to produce high-precision, high-quality parts and products, which are widely used in automotive manufacturing, aerospace, electronic equipment and other industries. However, the traditional mould polishing process often fails to meet the manufacturing needs of precision moulds, so the application of CNC machining technology has become an effective way to solve this problem. Through the use of CNC machine tools and computer control systems, etc., the detailed formulation of the process plan, so that precision mirror mould CNC machining can achieve high efficiency, accuracy and stability of the machining process, to improve the quality and productivity of the mirror mould. Therefore, the applied research on CNC machining of precision mirror mould is of great significance and economic value.

Additive technologies are becoming a common part of not only prototype production, but also piece or small series production. However, the choice of technology and material plays a key role in the applicability of the manufactured parts. The most widespread type of additive technology is FFF technology, which consists of applying a fused plastic string in single layers. The resulting mechanical properties of parts produced using this technology depend not only on the material and structure selected, but also on the process parameters used in the printing process itself. This study deals with the production of filament from PLA, which is the primary material. The advantage is its environmental degradability after the end of the life cycle of PLA products. However, the resulting properties of the printed parts may depend on the way the filament is prepared and in particular on the melt temperature during filament extrusion. This study investigates the effect of the produced filaments on the quality of printed parts. It has been shown that the filament production technology has a significant effect on the quality of printed parts.

The paper focuses on a novel and perspective surface treatment technology called Plasma Electrolytic Oxidation (PEO) applied to aluminium and its alloys. This innovative technology generates layers with specific properties, particularly suitable for tribological and heat-resistant applications. Plasma Electro-lytic Oxidation technology represents an alternative to conventional oxidation methods, offering high utility properties and presenting a completely new approach to surface modification.

The article highlights the promising potential of automating the forging process to enhance the durability of multi-cavity forging tools. Entrepreneurs aim to boost production efficiency by increasing output per unit of time and reducing the degradation of forging dies and punches. The high costs associated with specialized materials and complex manufacturing processes for these tools elevate the final product price. Automation offers a viable alternative, ensuring consistent process parameters and reducing the physical strain on workers. This consistency leads to extended tool durability, even without the use of special manufacturing techniques for their production. The study simulates the durability of multi-cavity dies in automated operations, demonstrating substantial advantages compared to manual forging. Simulation programs for forging processes and tool durability offer significant cost savings by providing insights into potential fatigue cracks, aiding in decision-making, and verifying operational parameters and tool designs. These simulations reduce the need for extensive: real-world tests and modifications of the forging tools.

This paper provides an overview of the commonly used processes and equipment for laser cladding, including pre-set powder feeding, simultaneous powder feeding, wire feeding cladding, and coaxial cladding nozzles. By comparing the above processes and related nozzles, the coating characteristics are summarized for the selection of appropriate methods and equipment in different working environments. Meanwhile, the morphology and properties of the clad layers of shaft parts processed with different process parameters (e.g. laser power, scanning speed, lap rate, powder feed rate) and the influence of the combined parameters are overviewed. The changes and mechanisms of metals, ceramics, and metal-ceramic composites in terms of hardness, wear resistance, metallurgical bonding, and microstructure are analyzed. In addition, the application of numerical simulation techniques to simulate the temperature and stress fields and to plan the melting trajectory when laser cladding processing is performed on the surface of shaft parts are reviewed. Finally, the problems in the current research on laser cladding of shaft parts are summarized and the development directions are discussed.

This paper introduces a customized Fused Filament Fabrication (FFF) printer, featuring an advanced electromechanical system that achieves a substantial 500% increase in printing speed compared to con-ventional FFF printers. This research scrutinizes the printer's capabilities, emphasizing the dimension-al accuracy. Specifically, this study focuses on the investigation of the effect of high printing speeds on the dimensional accuracy of linear artifacts. The material selected is Acrylonitrile Butadiene Styrene (ABS) and the FFF-fabricated parts are designed and measured based on the ISO ASTM 52902-2021 standard. Last but not least, statistical analysis and comments are following, showing remarkable re-sults on such high-speeds.

The work aims to present a design method of cam five-bar paper taking mechanism of packaging machine based on position and orientation constraints to better meet the position and orientation requirements of the end paper taking actuator in the high-speed paper picking process. At the first stage, according to the given ideal position and orientation requirements of the end paper taking actuator, the mathematical model of the five-bar mechanism satisfying the position and angle constraints is established by using the kinematic mapping theory, and two cams are used to constrain the two freedom of the five-bar mechanism to obtain the cam five-bar paper taking mechanism. At the next stage, the relationship between the five-bar mechanism and the cam angle under the given position and angle constraints is solved, and the theoretical profile of the cam is established by using cubic spline curve function. Finally, the whole paper taking mechanism is optimized to obtain the best mechanism parameters. Through the design example of the cam five-bar mechanism of the high-speed packaging machine, it is verified that the designed value taking mechanism can accurately realize the given orientation point, and there is no contour distortion of the cam. This method can not only realize the given position and orientation of the end actuator, but also further optimize cam profile of the paper taking mechanism to improve the running stability and accuracy.

The restriction of lead content in alloys for the production of the solder based on the Directive of the European Parliament and of the Council of the European Union of 08.06.2011 which is also known as RoHS (Restriction of the use of certain Hazardous Substances in electrical and electronic equipment), had a very positive impact on the research of lead-free solder alloys as well as on the economic impact on the production of solders. It opened the door to issues relating to the mechanical properties of lead-free solders and the microhardness of formed joints, increasing their quality and efforts to reduce production costs. Lead, as an element that is part of the earth's crust, is also men-tioned in his study by u-Wook Lee, Hoon Choi at all: Toxic effects of lead exposure on bioaccu-mulation, oxidative stress, neurotoxicity, and immune responses in fish, in which he states how lead atoms can form a flexible bond with oxygen atoms and lead exposure causes a wide range of physiological effects. Besides the production efficiency increase, without the need for manual re-moval of so-called slagging, the moderation of oxide formation on the melt surface standing for the increase of the yield of the total amount of solder represents one of the many factors influencing the production of lead-free alloys for tin-based soldering. This work deals with the issues of material selection for the production of lead-free solders. Temperature affects the formation of different phases when there is the change in the concentration of the elements involved because it can be negative aspect for soldering. Therefore, it is necessary to have detailed knowledge on all the process which takes place during the temperature changes.

Titanium and its alloys are an important structural material in all sectors of industry. Thanks to its mechanical properties. One of the most widely used titanium alloys is the Ti6Al4V alloy. If we heat alloys for a long time in an air atmosphere, TiO2 is formed on the surface of the parts. The Ti6Al4V alloy, also referred to as Ti64, is a two-phase alloy formed by α+β solid solutions from the point of view of microstructure, it is characterized by corrosion resistance and good biocompatibility. Through heat treatment, we can improve the mechanical properties of the alloy, improve the fracture toughness, influence and reduce the internal stress and influence the machinability of the material. To achieve a longer service life of products made of this alloy, we can use the method of surface treatment, in the form of nano layers. An analysis of the Ti6Al4V alloy was performed for the cell, after heat treatment at temperatures of 650 °C and 800 °C and followed by corrosion loading in a salt fog environment. The exposure time in the corrosive environment was between 168 and 720 hours. Changes in the microstructure were ob-served and the change in microhardness in the surface layers of Ti6Al4V was described.

Additive manufacturing is a relatively new technology that has recently undergone noticeable develop-ment, which includes several types of technologies based on the gradual deposition of material in layers. The most widespread method is Fused Filament Fabrication, which belongs to an extrusion technique. The typical feature of extrusion methods is material deposition in the filaments form. Therefore, printer users cannot apply the same approach to products as with conventional technologies. The authors of the paper have been working with the mentioned technology for several years. The primary goal of the research is the investigation how printing parameters affect the mechanical properties of laminates reinforced with chopped carbon fibres. Based on experience and knowledge, the authors report in this article the most common challenges encountered in the preparation process of specimens for tensile testing. This knowledge can also help ordinary users of 3D printers, who also face these challenges without being aware of the impact of these pitfalls on mechanical properties.

One of the ways to improve or change the surface properties of materials is to apply thin layers. TiO2-based layers are used to protect surfaces against wear or atmospheric and thermal effects (anti-corrosion, anti-abrasive and anti-static layers). They are also used in optical coatings, on windows or glasses (anti-reflective, self-cleaning and conductive transparent layers), in healthcare and in households to ensure the cleanliness of surfaces. The work deals with the effect of TiO2 layers on the surface properties of selected substrates. The layers were prepared by the sol-gel method using the dip-coating technique on glass and stainless steel. The morphology and topography of the surfaces of the uncoated and coated substrates were evaluated by atomic force microscopy. Scanning electron microscopy was used to determine the layer thickness. The effect of TiO2 layers on the surface properties of materials was also evaluated using wetting angles, surface energy and its polar and dispersion components. Based on the results, especially the higher surface energy value, we can conclude that the TiO2 layer influenced the surface properties of the studied solid materials.

The paper focuses on proposing a method for implementing key performance indicators (KPIs) to assess the effectiveness of manufacturing processes. For the evaluated processes of precision parts machining, the share of non-conforming products was proposed as a KPI, evaluated as both an exter-nal and an internal indicator. The external indicator EXTppm expressed the quantity of faulty prod-ucts to the volume of production. Its monthly development during 2022 was evaluated. The internal KPI represented the internal share of non-conforming products INTppm during 2022 which was re-lated to the order of part A. Towards the conclusion causes for not attaining the targeted KPI values are pinpointed, and recommendations are put forth to enhance the productivity of manufacturing processes.

The aim of the research was to assess the influence of additions of different proportions of alumini-um waste chips from the machining technology on the melt quality and final properties of AlSi7Mg0.3 alloy casts. All casts were created using by gravity casting technology into preheated metal mold. The first cast was a pure AlSi7Mg0.3 alloy, followed by other samples with contents of 10, 30, 50, 70 wt.% of aluminum waste chips in the batches. All the samples were subjected to the Brinnel hardness and Vickers microhardness of solid solution of α(Al). Also, Density index was measured. At the end of research, the microstructures of the samples were analyzed using a Laser Confocal Microscope Olympus Lext OLS 5000.

The tempering procedure of quenched 54SiCr6 spring steel was analyzed using continuous heating dilatometry, isothermal dilatometry, metallography, and hardness measurement. The dilatometry was performed on four different steel modifications with graduated Si content and with two levels of Cu. Metallography and hardness measurement were analyzed only on samples with one Si level. Two types of tempering procedures were compared in this experimental program. The first one was sim-ple one-step tempering, the other was a special procedure of strain assisted tempering (SAT), which includes double tempering and strain applications between tempering. A dilatometry analysis with the support of metallography contributes to the material behaviour explanation, which is considerably different in both processing cases.

The article is dedicated to research on the elimination of high iron content (above 3-4%) in aluminium alloys through sedimentation. The aim was to determine the effect of sedimentation time on reducing the iron content in material from a refining bath with high iron content and to identify the phases formed in the structure. Melts were prepared from the material obtained from the refining bath, which consisted of an AlSi12 alloy with 3-4% Fe content. After melting, sedimentation was carried out for 2 hours, 4 hours, and 6 hours. Sedimentation was conducted while maintaining the alloy in a liquid state throughout the entire sedimentation period. After sedimentation and cooling of the castings, samples were taken to prepare metallographic specimens, and analyses were conducted to measure the iron content in the individual samples and to observe the reduction of iron content depending on the sedimentation time. Additionally, the identification and description of the intermetallic phases formed in the structures of the sedimenting castings from the refining bath were carried out using a scanning electron microscope with EDS analysis.

The electrochemical discharge machining (ECDM) process is developing into a potentially useful method of performing micromachining in conductive or non-conductive materials. The materials are machined using a combination of chemical and thermal energy. This paper examines the effect of Artificial Neural Network (ANN) architectures combined with particle swarm optimization (PSO) on the predictive ability of tungsten carbide machining. Material removal rate (MRR) and surface roughness (SR) is the response used to evaluate the performance of the ECDM process. The four selected process parameters are voltage, gap width, electrode type, and type of electrolyte, with each parameter has two levels. The 4-9-1 structure was chosen to obtain pre-dictions in the form of an optimal formula based on the statistical values for surface roughness: MSE 0.001, RMSE 0.025, MAPE 1.36, and R2 0.99.

The task of comprehensive machine care, monitoring of reliability and maintenance is currently a priority not to wait for a malfunction, but to prevent malfunctions before they occur. In the possibilities of mod-ern diagnostic tools, this activity is the task of oil analysis, which is a highly effective tool for monitoring the condition of hydraulic oils during their long-term operation. It is possible to prevent the failure of the entire system by regular monitoring of the technical condition of oils based on the analysis of hydraulic oil pollution. Oil analysis can reveal the amount of additive elements, oil pollution, the amount of addi-tives and changes in the physico-chemical parameters of the oil. In order to determine the current state of the oil filling, it is necessary to use a suitable diagnostic method. The submitted contribution de-scribes an experiment aimed at evaluating the state of hydraulic oil by means of EDX (Energy-dispersive X-ray spectroscopy) analysis, DSC (Different Scanning Calorimetry) analysis and infrared spectroscopy.