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Very dynamic development in the field of computerization and industry robotization, as well as an im-plementation of the Industry 4.0 assumptions are the main reason for the increased demand for magnetic materials. The limited rare earths availability and the sustainable development in the field of material engineering indicate that the methods of recycling magnetic materials from Waste of Electrical and Electronic Equipment are necessary. This paper presents the impovement stages of magnets recovery process - extrusion process of magnetic scraps/particles with polymer (magnetic scraps and particles obtained from WEEE). The process is developed based on the Process Failure Mode and Effects Analy-sis. The reserch pointed the irregularities, that pose the greatest risk of failure in the process. The paper presents changes in the process based on the values of the indicators: severity (S), probability of occur-rence (O), probability of detection (D) and the Risk Performance Number (RPN). Based on the PFMEA, 5 operations were added to the process. Due to changes in the process course, it is possible to minimize the effects of the irregularities occurrence.

The objective of this paper was to investigate and respond to the quality and strength of CMT welds that were sub-jected to degradation effects and subsequently to tensile testing. The tensile test was recorded using AE acoustic emission. The experiment focused on the quality of CMT welds (Cold Metal Transfer) and the resistance of these welds to corrosion degradation. Welds are generally exposed to environmental influences such as high stress, stress and degradation effects. The combined effect of these factors may in some cases result in the destruction of weld joints. For this reason, emphasis is placed on the quality of welds and their resistance to environmental influ-ences. For this measurement there were ten samples prepared, divided into two groups, each having five samples. One group was subjected to corrosion degradation, while the other one was at the same time subjected only to envi-ronmental influences. Subsequently, all samples were subjected to tensile testing. The course of this test was rec-orded using the AE acoustic emission, where the AE sensor was attached to each weldment to record dislocations during the tensile test. Named values were evaluated in the Dakel–Daeshow program.

Effect of addition of cryogenic treatment to a standard heat treatment of aluminium alloy AW 7075 was tested in this work. Used heat treatment consisted of solution annealing at 470 °C for two hours and precipitation aging treatment at 130°C for 14 hours, 120 °C for 24 hours or natural aging at room temperature for 60 days. One set of samples was processed by solution annealing and aging treatment and the second set of samples incorporated 24 hours long cryogenic treatment at -185 °C between the same solution annealing and aging. Both sets of samples were characterised by tensile testing, notch impact testing, hardness measurement, microstructure analysis and wear and corrosion resistance tests. Obtained results were compared for corresponding processing with and with-out cryogenic treatment. While impact toughness and corrosion resistance were decreased by cryogenic treatment, tensile strength and wear resistance were on the other hand improved.

The experimental investigation of the vertical vibration of the vehicle is presented. The vibration of the two axles vehicle is excited by crossing of the vehicle over the transverse speed bumps on the road. The methodology is oriented upon the quarter, half and full model solution. The full geometry model is the most suitable model for the vertical vibration of the vehicle. The full geometry model is capable to describe geometric and construction asymmetry of the vehicle. The methodology of an analytical solution of the symmetry and asymmetry distribution of the vehicle and load is presented. Also, symmetric and asymmetric excitation is involved to the solution. The Heaviside?s function is applied for the excitation of vibrations. The presented methodology was applied to the experimental work with trolleybus Tr 21. The normalized speed bumps were used for the experimental setup. The vertical displacements, velocities and accelerations of axles, body of the vehicle. The acceleration of the vehicle chassis under driver seat was also recorded. This accelerations have significant effect on the comfort of driver and consequently on his/her fatigue and health condition.

This paper discusses the modeling and simulation results of a new multi-material for a cost-effective Selective Laser Sintering (SLS)-based 3D printer. As this technology utilizes several materials, the me-chanical property analysis of multi-materials is crucial for manufacturing an object with the desired physical characteristics. Firstly, the development of a database of the SLS 3D printing materials is ac-complished and based on the mechanical properties of materials, this optimization technique is proposed. Secondly, enhancement of physical property by stiffeners is considered and based on the stiffening tech-nology, and an alternative optimization method proposed. Finally, two different material minimization methods are discussed in this research. The first method is based on the embedded materials with desired mechanical properties for enhancing the mechanical properties of the printed objects, which are twice optimized by this method with increased material saving. The second method is designed to use stiffeners to improve the stiffness characteristics of the materials, and then, perform material optimization. This method is effective with more suitability to complex composite geometries. Thus, the methods help to reduce materials used as well as the production cost in 3D printing technology.

Ceramic composite materials based on boron carbide were hot pressed utilising in situ reaction of boron carbide powder with 40 wt.% of titanium dioxide sintering additive. The samples were prepared at sintering temperature of 1850 °C, pressure of 35 MPa, and time of 60 min in vacuum atmosphere of about 20 Pa. Optimisation of sintering regime concentrating on both heating stage of sintering and application of pressure enabled to prepare fully dense ceramic composite materials composed of boron carbide matrix with 29.5 vol.% of titanium diboride secondary phase. The ceramic composite reached average density of 99.3 %, hardness of 29.8 GPa, and fracture toughness of 6.9 MPa.m1/2.

This paper describes a search for an optimal organization of the drying agent motion in the convection dryers. An overview of the main methods on how to reduce the energy consumption for the convection drying of the disperse materials is presented. The use of the multistage shelf apparatuses with a differential thermal regime for the con-vection drying of the disperse materials is justified. The work contains the results of a computer modeling on de-termining the drying temperature and moisture characteristics with the use of various methods of the organization of the drying agent motion. The model is realized implementing the author?s software product Multistage Fluidiz-er?. The software product enables to automatize calculation simultaneously by several optimization criteria and to visualize calculation results in the form of 3D images. The engineering computation of sectioning devices meth-odology with fluidized bed of particles is based on the calculation results. The automated calculations results give a base to design industrial drying device with a differential thermal regime.

The article presents the results of theoretical research on creating the mobile continuous earthmoving machinery. The aim of the article is to develop and evaluate the effectiveness of technical decisions when creating and mod-ernizing trencher chain and bar actuators. The peculiarity of the performed research is a complex way to solve the problems of ensuring the efficient operation of the earthmoving machinery. It involves a combination of two subsystems: "soil - operating equipment" and "basic chassis ? bearing capacity of soil surface". The mechanisms of changing the power parameters of the machinery load are established. The input parameters for a system de-scribing the operation of a special earthmoving machinery are soil physical and mechanical characteristics and the dimensions of the earth excavation, the installed power of the basic chassis engine, the type and characteristics of transmissions of the machinery operating equipment and chassis propulsion, geometric parameters of single cutters, the speed of cutting the soil and moving the machinery. The mathematical model of the system as a whole makes it possible to determine the rational design, kinematic and energy characteristics of the machinery and its operating equipment. It minimizes the energy intensity of soil development.

The article deals with analytical and experimental solution of vertical oscillations of a mechanical system of bound bodies. The content of the article is to perform an analytical solution of the vertical oscillation of a system of bodies using the computer program MathWorks Matlab and MS Excel. Furthermore, an experimental investigation on a laboratory model of a mechanical system of the same parameters was proved. The aim of the work was to compare the analytical solution with the experimental method and to check the accuracy and applicability of analytical methods for the solved mechanical system.

The subject of the article is a comparison of new and used powder for 3D metal printing. The powder is 316L stainless steel manufactured by Renishaw. The powder used was taken from the RENISHAW AM250 printer after use. Powder manufacturer Renishaw recommends using 15-45 micron powder in their 3D metal printers. An im-portant parameter of monitoring is the chemical composition of the metal powder and its changes during the thermal treatment during laser sintering. Another important parameter of a metal powder is its mechanical prop-erties, which determine the flowability, consistency and uniformity of powder application. By using an inert at-mosphere for sintering and storing the powder, these chemical changes can be prevented, especially against the formation of nitrides and oxides at elevated temperatures.

Small holes can be manufactured by several ways. It is important to define in what dimensions the small holes vary. Anyway, drilling is one of the oldest technologies of holes manufacturing. In small dimensions we use the term microdrilling for description. Beside this conventional way of manufacture there are also unconventional methods. Microdrilling bits very often break before they are worn. Therefore, the tool life of these bits its quite unexpectable. It is due to relatively high load against the drill bit strength. So, it is important to choose proper drill bit material, cutting geometry, construction, process liquid, clamping and cutting conditions. These parameters are import for achieving ideal conditions for microdrilling. Even a tiny change in pre-seted parameters can lead to destruction of these delicate tools. Fiber arrays are designed and manufactured for precise positioning of optical fibers in row (1D) or in plate (2D). Fiber arrays can contain most of fibers including polarization maintaining fibers (PMF).

Scratching force is a significant factor to evaluate the characteristics of single diamond grit scratching process. In this paper, experimental study was carried out to investigate the vibration characteristics of force signals during the scratching process. A precise multicomponent dynamometer is employed in the force measurement during a single diamond grit scratching on pure copper. The frequencies of the vibration section of force signals with different scratching parameters are calculated and analyzed. The influence of force signal vibration on the measuring accuracy of dynamometer is systematically analyzed further. The results show that higher scratching speed and larger scratching depth lead to larger vibration amplitudes of the force signals. Strong impact on the quartz piezoelectric crystal of dynamometer, which is produced indirectly by single diamond grit scratching process, leads to the vibration of scratching force signal. The first semi-sinusoidal force signal is the actual scratching force. The vibration of the scratching force signal has little effect on the measuring accuracy of the dynamometer.

The paper deals with dynamic in-plane simulation analysis of a motorcycle suspension. The motorcy-cle᾿s mechanical model is considered as a visco-elastically suspended rigid body. Two types of the kinematic excitation are considered ‒ a deterministic „hat“ shaped bump and stochastically uneven road characterized by its power spectral density. The simulation results for both the deterministic bump and stochastically uneven road show that significant reduction of the root mean square value of the motorcycle body centroid acceleration (comfort criterion) can be achieved by placing the lower end point of the rare spring-damper module closer to the beginning of the swinging arm and also by increasing deviation (tilt) of the spring-damper module from the vertical. The maximum improvement in the root mean square value of the motorcycle body centroid acceleration is 51.7 % for the deterministic „hat“ shaped bump and 37.4 % for the stochastically uneven road. The method presented in the paper can be employed in design of both touring motorcycles, which are characterized by higher requirements of comfort, and off-road motorcycles where protection from impacts generated by bumps is important.

The 54SiCr6 steel belongs to spring steels which excel high strength and at the same time reaches high values of reduction of area and sufficient value of elongation. Nowadays, new methods are searched and examined how to get better properties from materials, higher strength and toughness, longer fatigue resistance or better corrosion properties. In the case of silicon-chromium spring steels, innovative heat treatments are investigated such as quenching and partitioning which enables to achieve higher ductility of steel due to higher content of retained austenite. The way of modification of the chemical composition of the 54SiCr6 steel was chosen in combination with conventional heat treatment composed of quenching and tempering to get better properties. The materials with in-creased content of copper to 1.5 wt. % and silicon to 2.5 wt. % were prepared. The influence of alloy-ing elements on microstructure and mechanical properties was followed up to the tempering temper-ature of 400 °C.

The magnesium alloys, alloyed by the low amount of calcium and zinc concurrently, are considered as a biodegradable materials for implants. However, the as-cast alloy exhibits the insufficient mechanical properties as well as corrosion resistance which are affected mainly by the presence of brittle secondary phases, such as Mg2Ca. For this reason, presented work was focused on the as-cast magnesium alloy with alloying elements (Ca and Zn) whose content did not exceed 1 wt. %, specifically MgCa0.5Zn0.5 (in wt. %). Microstructure consisted of magnesium matrix with a very low amount of Mg2Ca and Ca2Mg6Zn3 phases which crystallized along the boundaries. These phases and their localization influenced the resulted mechanical properties. The hardness was higher due to them and tensile properties were worse than the compressive ones. The addition of zinc did not improve ductility, but in the case of compressive stress-strain test, the relative deformation was satisfactory. Moreover, the corrosion resistance of as-cast alloy MgCa0.5Zn0.5 was better than pure magnesium.

Colour metallography, especially colour etching, is a widely used technique for visualizing different phases in the structure of metals. Its advantage to the traditional etching techniques is that it gives additional information about the structure of material. The paper deals with the structural analysis of graphitic cast irons with a focus on colour etching. The possibilities of extending information about the structure of cast irons using colour contrast compared to classic black-and-white contrast is discussed. The paper is supplemented by photographs of microstructures of graphitic cast irons, obtained using classic black-and-white methods, as well as colour etching. Colour photographs of the structure of cast irons were obtained using the light metallographic microscope Neophot 32 with a digital camera Nikon DS-Fi3. Selected etchants for traditional black-and-white etching and for colour etching were used.

The macroscopic structure of a casting has a direct impact on its mechanical properties. The porosity and homogeneity of a casting closely correlate with its tear strength characteristics. In order to achieve the best mechanical properties, it is necessary to eliminate internal defects in a casting. The elimination of such defects can be achieved through the suitable adjustment of the input parameters of high pressure die casting machines prior to starting the actual casting cycle. This method is useful for companies that produce castings on the basis of supplied pressure forms, whereby it is impossible to influence the design of the gating systems. A much more appropriate way to influence the homogeneity of a casting is to design the gating system so that possible shortcomings are already underpinned and excluded in the design and development phases. By adjusting various elements of the gating systems it is possible to achieve significant improvements in the properties of a casting. The construction of the gate has the biggest influence on the final homogeneity of a casting. The gate is the point at which the modulation of the melt flow rate takes place for the filling of the die cavity. The mode in which the cavity is filled and the speed of the melt flow rate are the main determinants of the final characteristics and properties of a casting. This paper presents an analysis of the macroscopic structures of castings produced under various gate construction modifications and their effect on the mechanical properties of those castings. Conclusions, which are drawn on the basis of the detailed analysis, describe the correlation between the macroscopic structures and the mechanical properties of castings with precautionary measures that are used and implemented directly in production.

The paper considers the question of slipping and skidding occurrence probability decreasing by means of the friction controlling in the wheel-braking pad and wheel-rail contacts. One of the methods of stabilization of the friction in the pairs is a temperature control system based on the use of constructive and technological elements for the absorption and removal of heat from the friction pairs to the environment. The variants of technical solutions on multifunctional (temperature, abrasive) controlling tribocontacts by energy of air, air-abrasive stream or pellets of dry ice, electrically charged sand supply are proposed. Achieving optimum amount of supplied sand to the wheel-rail tribocontact is proposed through its charging using tribostatic or electrostatic methods. Presented the results of experimental research on the "Friction Machines" are the dependencies of the friction coefficient on the temperature.

The physics features of the cutting process of ultrafine-grained metals produced by the method of severe plastic deformation are considered. The aim of the research was to evaluate, whether the grain size of titanium alloy has an influence on the characterization of chips, the cutting force components, the surface roughness and the microhardness in the cutting process. The experimental data of the machineability of titanium alloy Ti-6Al-4Mo with sub microcrystalline structure are presented in the paper. The features of the chip formation, the changes of the chip ratio and the components of the cutting force are examined. The main characteristics of the cutting mechanics are calculated and based on the experimental values. Also the experimental values of the surface finish roughness and microhardness are shown. It is established, that the change in the structure of the metal has an ambiguous effect on machineability by cutting. Further investigation of the machineability of metals with a submicrocrystalline structure will allow to choose the efficient mechanical treatment.

Polymeric materials are thanks its processing and utility properties materials in demand of common and special use. They are also largely replacing conventional materials. As the popularity of polymeric materials grows, also the amount of its waste increases. For this reason, there is introduced the term recycling as a method of processing, re-use of the waste, into technologies of polymeric processing. So, this paper deals with the possibilities of introduction of recycled material. The main part of this paper is created by an experiment that explores the changes of tensile properties of test specimen according to the selected percentage of additives in the volume of the basic granulate. The test specimen was produced by mixing pure granules with the addition of recycled and re-granulated materials. The conclusion of this work presents a comparison of the results of each tensile test that provide an overview of the behaviour and properties of the materials tested.

A new comparison method of the total forces for different contact areas has been published which allows increasing determination accuracy for cutting forces on flank surface. In this regard, on the basis of the new method the laboratory of the Department of Machining and Assembly of the Technical University of Liberec has carried out a study to determine the effect of tool wear on the correlation of forces on the face and flank surfaces of the cutting tool when cutting various materials.

A properly designed and engineered gating system for use with high pressure die casting technology will produce castings with excellent mechanical properties. The gating system must secure the fast and continuous filling of the cavity. An appropriately designed and structured gating system can reduce the length of the die casting process, thereby increasing the effectiveness of production, reducing the amount of waste, and delivering cost savings. This article focuses on the structural analysis and optimization of runners and their impact on the mould casting of a specific light-weight casting made of AlSi alloy.

Theoretical analysis has been carried out for the determination of the analytical dependences connecting various parameters of contact area between wheel cutting surface and workpiece, such as length, width and arc length in the case of flat face grinding with preliminary inclination of spindle axis. The role of factors, such as angle of preliminary inclination of the spindle axis, grinding depth and grinding wheel diameter, in this process, are established. The capability to define the above mentioned parameters permits the calculation of the contact area between wheel cutting surface and workpiece. In addition, with the proposed methodology, it is possible to correctly determine the value of cross-feed, in the case of multiple-pass processing scheme, which, as it is known, should be consistent with the value of contact width of wheel cutting surface with workpiece. It can be guaranteed that on the ground surface there will be no areas unaffected by the wheel. In the case of through-feed grinding the obtained theoretical dependences make it possible to determine the processing conditions, taking into account the allowable value of flatness deviation. Finally, the latter, contributes in improving flat face grinding process and thus expanding its technological capabilities.

The design of the gating system is a major factor in the internal homogeneity for casting. A properly designed system should ensure a proper and continuous filling of cavities in a mold. A continuous filling in a mold cavity gives the initial condition for internal soundness and homogeneity when casting, which in turn is reflected in the quality and mechanical properties. The geometry and shape of the gate models and directs the melt stream entering the mold cavity, this greatly affect the properties of the castings. Homogeneity of castings closely correlates with the mechanical properties of castings. The present paper is devoted to analyzing the effect of the dimensions of the inlet slit on the homogeneity of the casting. As the width of the gully is constant according to the design method of the ingate systems, the variable parameter was the height of the gate. The aim of the experiments was to find the most advantageous height of the gate that is necessary to achieve the lowest porosity values. The boundary values of the height of the gate were determined based on the numerical design of the ingate system for the particular casting and the NovaFlow & Solid simulation program. The porosity analysis f was performed by the OLYMPUS GX51 microscope and the evaluation of the samples was carried out using the ImageJ computer program.

This article presents a new technology of obtaining the flat products with an ultrafine structure. The ultrafine-grained structure is obtained by using severe plastic deformation which is developed by the helical rollers. The stress-strain state (SSS) of the workpiece during rolling process in the helical rollers and longitudinal wedge mill is investigated in this scientific paper. The quantitative data has been obtained by the finite element method and MSC.SuperForge software; as well as the basic SSS distribution patterns, the temperature in simulating the rolling in the helical rollers and longitudinal wedge mill with different number of passes and the single reduction have been established. The rational technology of rolling the two-phase titanium alloys was developed and tested in the laboratory. The special attention is paid to analysis of the influence of the rolling conditions in the helical rollers and longitudinal wedge mill on the formation of VT6 titanium alloy microstructure.

This paper presents a development and design of new multifunctional clamping jaws for thermomechanical simulator. In the article there is presented what the thermomechanical simulator is and what is it used for. The article also describes the requirements for the thermomechanical simulator jaws and how they were achieved. All important parts of which the thermomechanical simulator jaws are assembled and used are described in detail. Finally, thermal simulations of the jaws were performed under operating loads. This technical solution is protected as a utility model registered on The Industrial Property Office - Czech Republic.

The ratio of primary and secondary alloy in the batch is important in determining and evaluating the quality of the alloy. The resulting quality of the casting and the costs associated with its production are directly related to the composition of the raw materials entering the smelting process. With the use of an alloy composed of a high proportion of recycled material a negative effect on performance can be expected despite its economic benefits. Based on the results of thermal analysis, mechanical properties and microstructure analysis, the effect of changing the primary and secondary AlSi9Cu3 alloy ratio in the batch was determined. A negative effect of the increasing proportion of secondary alloy was already evident in the case of an alloy composed of a 50-50% ratio. Conversely, in the case of artificial aging, a positive effect was observed with increasing amounts of secondary alloy.

Zinc-based materials show large potential to become biodegradable materials with ideal corrosion behavior in the body environment. In this study, a zinc composite containing 8 wt. % of hydroxyapatite (HA) was prepared by spark plasma sintering (SPS) and characterized from a point of view of the microstructural and mechanical properties. The influence of pre-processing (milling) of the powders on the microstructure after the sintering was studied. The materials prepared by the milling and subsequent sintering showed insufficient cohesion due to the wrapping of Zn by HA particles and possible oxidation of zinc particles. Compressive and flexural tests of sintered materials prepared without any pre-processing confirmed the role of hydroxyapatite as a defect in the Zn/HA8_SPS structure. The results of the hardness measurement suggest that the HA does not affect the behavior of the zinc matrix.

Using innovative methods of heat treatment (HT) for high-strength steels, such as the Q&P process, very favourable ratios of ductility and strength can be achieved. Materials processed by this technology have higher content of retained austenite, and therefore better ductility. This experiment deals with HT of 42SiCr steel. The conventional HT and the Q&P processing are compared with respect to material properties. Metallographic analysis, hardness measurement, X-ray diffraction phase analysis (of retained austenite content) and tensile testing were performed. For the hardened samples, the effects of the cooling rate on their microstructure were assessed and the measured real-world data were compared with the simulations performed in the FEA simulation software DEFORMTM based on the thermocouple records. After a conventional HT, the material showed little sensitivity to the cooling rate. In contrast, the Q&P process with higher quenching temperatures resulted in a higher austenite content and elongation of up to 15 % at a strength of 1800 MPa.

There are a lot of basic material characteristics that can generally describe the behavior of material. Among them, anisotropy coefficient rα [1] represents a very important material parameter - especially in the area of metal forming. Acc. to standard is such quantity determined as width and thickness strain values under the given magnitude of deformation. It means that anisotropy coefficient rα is always determined at one point (magnitude of deformation). In this paper was applied the contact -less optical system ARAMIS to determine values of rα through the whole static tensile test - more precisely from yield strength up to uniform ductility. Thus as a result there are curves of anisotropy coefficient vs. engineering strain for 3 rolling directions (0°, 45° and 90°) and their values are in the given points compared to the "standard" ones (conventional approach).