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Metal machining is a complex technological process based on material removel from semi-product by the influence of a cutting tool which is abrasion-resistant at high mechanic and heat strain. The essence of material removal is based on considerable material plastic deformation under the tool cutting wedge, the result of which is a deformed chip and transformed workpiece surface, which must comply with the geometrical and mechanical workpiece characteristics. These are determined by selected cutting conditions, geometrical and mechanical characteristics of the cutting tool. The selection of cutting conditions is engineering art and requires deep knowledge of machining process, mainly the relationship between cutting conditions and ther results of machining. These relationships are being tried to identified in the paper.

The turning process is one of the most common machining operations in various manufacturing industries. It is conducted by eroding the rotating workpiece using a tool that moves in a linear motion. This study examined the genetic algorithm (GA) as the optimization method for the dry turning process of AISI 316L. GA is a meta-heuristic method that imitates the principle of natural selection, in which the most suitable individuals are selected for reproduction to produce the next generation of offspring. The optimization process was started by executing the selected experimental design based on the process parameters and their levels. The tool nose radius, cutting speed, feed rate, and depth of cut were selected as the process parameters in this study. The outcome of this step was a fitness function that explained the relationship between the process parameters and the material removal rate (MRR) or the surface roughness (SR). GA used the fitness function to produce the optimal process parameters with the highest MRR and the lowest SR in a separate optimization process. The optimization methodology developed in this study can be utilized to predict the optimum value of the MRR and SR for the dry turning process and with less than a 7% deviation from the actual value.

The article deals with the application of computed tomography in dimensional quality control. The advantage of computed tomography is that the measured part is not influenced by measuring force. It is possible to measure complex parts and assemblies, their geometry, internal structure and defects in one step. The disadvantage of CT is decreasing accuracy and resolution when measuring hi density materials or larger parts, which leads to usage of high accelerating voltage and current. The measurement result is influenced by many factors, not only the instrument itself and the set of measuring parameters, but also largely depends on the sample itself, on its material and geometry. Based on the requirements for dimensional inspection, an analysis of the dependences of individual parameters of the Zeiss METROTOM 1500 computed tomography was conducted. The dependence of the spot size of the X-Ray source on the accelerating voltage and current was determined for the given instrument, as well as the relation between the voxel size and the distance of the sample from the detector. Spot size and voxel size has to be in relation, since large spot size goes against high magnification, high resolution meaning small voxel size. Using calibration artefact, the influence of the acceleration voltage on the accuracy when measuring form and size of a sphere and the distance between centres of 2 spheres was evaluated.

In order to improve the surface machining quality of slow tool servo (STS) turning in complex sur-faces, the optimal method of tool path generation (TPG) was studied. Taking into consideration the problem of large discrete errors and interpolation errors in TPG, equal height discretization method and interpolation algorithm for non-uniform nodes were proposd and the acceleration continuous condition was introduced. Simulation results showed that equal height discretization method could reduce the discrete error by more than 70%. The interpolation errors could be reduced to two orders of magnitude by transforming segment cubic Hermite interpolation into segment cubic spline inter-polation. Finally, the processing experiments were performed. The results showed that the form error PV value for the workpiece of the toric surface obtained by equal height discretization method and non-uniformity processing and segment cubic spline interpolation reached 0.002mm. The PV value of the sinusoidal array surface was about 0.009mm, and its surface roughness value was 0.064μm. The results proved this method can effectively reduce the discrete errors and interpolation errors, as well as improve the surface machining quality.

The article presents the results of the use of quality instruments – tools and techniques – in order to reduce surface defects of steel structures on the example of a selected element – engine cover of asphalt milling machines. The article shows the potential of using selected quality tools – basic and new – in the service of quality analysis and improvement. Quantitative analyzes were presented out using the Pareto-Lorenz diagram and the c control chart, qualitative analyzes using the Ishikawa diagram and the FMEA method, quantitative & qualitative analyzes using the interrelationship diagram and matrix diagram, and it was proposed quality improvement using qualitative tools such as affinity diagram, and PDPC diagram. The most common defects of painted surfaces turned out to be improper thickness and surface contamination. As it has been shown, the experience of employees is largely responsible for the cause of these defects, which was also confirmed by other analyses carried out with the use of quality tools. The training was the most frequent method of prevention. It has also been shown that special attention should be paid to quality control, its effectiveness, and quantity. The article proves that correctly used quality tools can contribute to the improvement of the quality of manufactured products, helps in solving various quality problems.

This paper deals with the topographic evaluation of samples made from materials applied in biomedicine. Different samples were made from Ti, TiAlV, TiNb and austenitic steel – Fe were used together with different surface morphology created. These samples were coated with a layer of TiNb alloy. The goal was to measure surface roughness in individual samples of biomaterials and to evaluate a 3D measurement of surface morphology made with a confocal microscope. Another task was to compare with appropriate software the pictures of material topography acquired at lower and higher magnification. Lower (10x) and higher (200x) magnification was used. For measured data evaluation SPIP and Gwyddion software were used. The same method of surface treatment was used but on different samples, which can lead to different results. The values obtained from topography measurements are crucial, but their formulation or evaluation can be affected by different processing methods. Our interest was to find and record the theoretically best procedure for the evaluation of measured data. Then to better understand the cell adhesion and integration of bacteria, we dealt with visualization of topography of given samples.

This thesis deals with deformations originating from heat treatment of the bearing metals. This is about the comparison of the heat treatment by rotating method in which the parts are feeded individ-ually into the rotating device and heat treated on hardening equipment in continuous way with high capacitive power. After the heat treatment it follows the operations of the grinding of the faces and diameters of the bearing rings. After the hardening we take into account two parameters, which may be mostly affected by hardening process namely: flatness of the faces ( cradle) and outer diameter ovality. Each of such deviations has got adverse influence during the grinding, therefore the hardening tech-nology is in most cases focused on elimination of this problem. The results of the heat treatment with higher deformations were confronted with values achieved by simulation software SYSWELD used for heat-metalurgical analysis.

The present contribution examines the structures of and corrosion processes in copper-basalt composite laser claddings on a steel substrate. The cladding material was a laboratory mixture of the following components: Oerlikon METCO 55 (Cu > 99.9 %) + basalt dust. In this investigation, metallographic structures of copper-basalt composite laser claddings were studied using optical and scanning electron microscopy. The adhesion of the claddings to the substrate was testing using the non-standardized Mercedes test. A potentiodynamic corrosion test in artificial mine water was performed on a specimen of the composite laser cladding. The test results were compared against those for a reference high-purity copper standard and AISI 304 steel. The findings were interpreted in terms of the potential of using copper-basalt composite laser claddings as corrosion protection coatings on steel components in nuclear power generation.

In This study vanadium carbide coatings obtained by thermo-reactive deposition/diffusion (TRD) technique on cold work tool steel AISI D3. The TRD treatment were carried out in a molten mixture consisting of NaCl, CaCl2, ferrovanadium and aluminum, by heating this mixture at 1000 °C for 4h using a resistance-heating furnace under air atmosphere. The coating process was investigated using light microscopy LM, scanning electron microscopy/energy dispersive spectroscopy SEM/EDS, and X-ray diffraction XRD characterization techniques. The results indicated that the vanadizing process produced a homogeneous coating layer about 13 µm depth and its microhardness is 2300 HV. Carbide compounds that are formed are vanadium carbides phases (V8C7, VC, V4C3, V6C5, V2C), while EDS-Line scan results show chromium carbides phases formed in sublayer. The corrosion resistance of the vanadium carbide coatings was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in a solution of 3.5 % NaCl. Vanadium carbide coatings improved the corrosion resistance of the substrates, vanadium carbide coatings showed the longest service life compared with the uncoated tool steel AISI D3.

The paper describes the possibility to streamline the process of modal parameters estimation performed on the washing machine heater. As the shape of the mentioned part does not allow to capture its response to excitation using conventional gages of acceleration, Polytec PDV-100 vibrometer based on laser Doppler vibrometry method was used. Such a non-contact device captures the response in a form of velocity only at one point in one direction. For that reason, the process of modal parameters estimation can be relatively timeconsuming, especially in case if the vibration of the analyzed structure occurs in more than one direc-tion. The authors speed up the process of response capturing using full-field high-speed digital image corre-lation system Q-450 Dantec Dynamics allowing investigation of the displacements in three mutually perpen-dicular directions. Its adaption for experimental modal analysis was ensured by developing an additional software called DICMAN 3D. As the output from the stereo camera system is in a form of 3D displacements in time, DICMAN 3D allows evaluating a single or multi-reference measurement using several algorithms. As the operational temperatures of the heater change due to the chosen wash cycle, the authors used numeri-cal modeling to analyze the influence of the temperature on the heater natural frequencies shift.

The paper derives mathematical and ggraphical relationships between technological parameters and result of metalworking, in the application of progresive cutting materials based on coated cutting tools of sintered carbide and cutting ceramits. The development of new cutting and machined materials leads to new perspectives on their interaction in the machining process. This process leads to patterns between cutting conditions and machined results. These need to be defined and used in favor of efficient machining of mechanical components in practice.

Marine ships engines are kind of huge diesel engines. In fact, the manner of controlling the speed of a ship can impact badly on the financial matters of the machinery operation. Thus, controlling the speed of the marine engines can avoid ships to face dangerous accidents. In purpose to prevent such kind of damages, marine systems simulator have been widely used as numerical tools. In fact, the simulation of speed control systems makes it possible to render the process of controlling the speed of an engine economical and eliminates many risks. In this article, we first present a mathematical formulation to illustrate the rotational velocity process of a ship model's marine diesel engine as well as its PID controller. Secondly, we introduce a novel python's marine simulator which includes a PID controller to govern marine ship model's engines and we compare its results with another PID diesel engine speed controller that we modelled, designed and simulated via Matlab/Simulink. Results of scenarios and experiences which we carried out have shown that the response of the speed control system when using python can be accurate and close to the one of Matlab/Simulink.

The present paper discusses the possibility to use three different sources of concentrated heat stream to repair superficial defects on AlZn10Si8Mg alloy castings. Simulated defects were prepared on specimens taken from a production casting made with the use of low-pressure casting method. The energy sources used to repair the defect were those known as MIG/MAG, TIG, and ML (micro-laser) methods. As the filler, a AlSi5 welding wire was used. The quality of repair was assessed based on both destructive and non-destructive testing. To evaluate porosity of the performed overlay welds, the computer X-ray tomography technique was employed. Metallographic examination was used to assess macro- and micro-structure of overlay welds, measure geometrical parameters of the welds and the heat-affected zone, and determine values of SDAS microstructure parameter. Hardness of overlay welds and parent material was measured with the use of Brinell hardness machine.

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 effect of the nitrocarburizing process in pastes with heating in a chamber furnace on the struc-ture and strength characteristics of 09Cr15Ni8Al corrosion-resistant steel was investigated. The tech-nology of chemical-thermal treatment was developed, which included nitrocarburizing in pastes with heating in a chamber furnace at different holding times. The thickness of the diffusion layer and its microhardness were determined after nitrocarburizing. To determine the efficiency and select the modes of chemical-thermal treatment, tests were carried out for the investigated steel's strength characteristics. The main feature of the structure of the diffusion layers of valve steels, obtained by nitrocarburizing in the nitrogen-carbon paste, is the presence of an inhomogeneous layer with clearly distinguished zones.

Planning a process of production, among other machining processes, is an important stage in the production of products. The developed machining process should allow production of parts with the planned dimensional accuracy and specified surface roughness. With reference to the above, the scope of the carried out theoretical work included determining the dependences between parameters of the drilling process, tool wear, as well as the impact of these parameters on the hole quality. The main aim of experimental research was to analyse cutting tools wear in various phases of tool usage. The research consisted in observation of metallographic microsections to analyse changes occurring in the drill bit microstructure. Then the microhardness was measured and in the next step the micro-hardness of the tested drills was statistically compared. Based on the results obtained, the percentage of wear for drill bits depending on microhardness was estimated taking into account the earlier esti-mated Percentable Production Cycle (PPC). This allowed determining the degree of wear and tear of drills by comparing the microstructure and microhardness between them. The aspects of cutting tool management are also discussed.

Aiming to improve the working life of high-speed rail bearings, this paper puts forward a comparative study on different types of high-speed rail bearings at extreme low temperature. The model of bearing life is established. In the whole test process, it is found that the change trends of bearing temperature, environment temperature and torque are basically the same. In the equilibrium temperature relationship between SKF and ZH bearings, the temperature divergence of SKF bearings finally appears. In the ZH bearings, bearing 4 appears irregular sharp drop at the end. However, the temperature changes of the two brands of bearings are between-150 ℃ and -170 ℃. And the friction coefficient is proportional to the ratio of torque. In the comparison of grinding amount, the wear amount of ZH bearings is far lower than that of SKF bearings, with a difference of about 0.5 mm. This shows that the production process and surface treatment methods of the two types bearing are completely different.

A new Coupler Critical Dimensions (CCD) approach to define mobility criteria (crank, rocker conditions, or existence) for linkage mechanisms has been presented in this paper. The idea is to analyze the extreme lengths of a mechanism coupler link when the mechanism is on the extreme of its existence or changing its mobility condition. The method leads a set of expressions of the constant mechanism parameters that can be used to define the exact dimensional limits of the coupler link in the mechanism. These expressions present sufficient and necessary dimensional conditions for the mechanism existence and become a turning point to change its mobility from crank to a rocker and vice versa. At the boundaries of the coupler dimensions, the mechanism reaches its the change-point configuration where the mechanism may switch either from one work function to another or from existence to non-existence. The method has been successfully applied to the planar 4R, spatial RSSR, and planar multiloop linkage mechanisms. The obtained results prove the effectiveness and accuracy of the method in defining the limits of the mechanism rotatability conditions or existence in general.

The paper describes a procedure for calculating the lifetime in the frequency domain, which is supplemented by an experiment. The aim of the experiment was to find the required mechanical properties of the material to describe the behavior of the material during fatigue analysis. Experimental modal analysis was performed to estimate damping, which supported numerical calculation and refined results of numerical simulations. The authors made an estimate of fatigue curve (SN-curves) according to ČSN 42 0363 and ČSN ISO 12 107 standards. Knowledge of material fatigue, statistics, modal analysis and signal processing were used in the experimental and numerical part.

With the increase of hydro generators capacity and unit size, the requirement of lightweight is prominent. Taking a mixed-flow hydro generator as the research objects, the strength, the stiffness and the dynamic characteristics of upper bracket, stator frame, lower bracket and head cover have been simulated and analyzed by means of establishing their finite element models. Based on sizing optimization design method, plate thicknesses of the main parts were selected as the design variables, and strength and stiffness were taken as the constraint conditions to optimize them with the minimum mass as the objective function. Through lightweight optimization design, the maximum normal stress and maximum displacement of the optimized main parts are within the allowable value range, modal analysis shows that their dynamic characteristics meet the requirements. The lightweight optimization design reduced the weight of hydro generator by 3457kg in total. Optimization effect evaluation under full load operation and site test between the original and improved hydro generator set show that the dynamic characteristics are improved and the performances meet the design requirements.

In this paper, the dependences of the tangential component of the velocity of movement of the medium granules, inside the oscillating reservoir, on its radius and oscillation period are obtained. For the anal-ysis, the circulatory motion of working medium granules under the influence of a rotating impeller and the dynamics of a pseudo-gas from abrasive granules exposed to rotating processed parts and an im-peller, are considered. From the results, the comparison of the energy impact on the working medium of the rotating processed parts and the impeller is carried out and the distribution of the pseudo-gas velocity from the abrasive granules and its pressure on the surface of the processed parts are obtained. Furthermore, the mechanism of pseudo-gas flow around a rotating part from granules of the working medium is presented. Finally, the schemes of the arrangement of the part in a cylindrical reservoir and its flow around the lateral surface of the rotating part are shown.

Taking a brake drum as the research object, the dynamic characteristics analysis and optimization designare carried out by using the finite element method.In order to increase the stiffness without increasing weight of brake drum, the main design parameters were tested by Box-Behnken experiment design. The three-dimensional model of brake drum was established by using SolidWorks software, then the finite element model of brake drumwasobtainedby imported into ANSYS software and its modal analysis was carried out. On the basis of modal analysis, the three important dimensions of brake drum were defined as input parameters, the drum weight, the first, second and third natural frequencies are defined as output parameters. The response surface model between the input and output parameters was established by using DOE (Design of Experiment). Finally, the input parameters were optimized by multiobjective genetic algorithmand the fivePareto solutionswas obtained. The fifth solution was chosen as the optimal solutionbased on the production technique.The weight of brake drum was not changed obviously after optimization, but the first, second and thirdnatural frequencies were increased by13.07 %, 8.92 % and12.73 %respectively, which provided a new idea for the design and optimization for brake drum.

The paper deals with the process of solidification of a cast aluminium piston into a metal mould (mould). The introductory part presents the methodology of solution where the physical properties of both the aluminium alloy and the steel mould are presented. Furthermore, the solution itself is described, which is performed on one quarter the size of a piston model by using FEM in the ANSYS FLUENT program. Piston solidification temperatures were recorded every five minutes due to the solution complexity. Next part of the paper pre-sents the evaluation where temperature sections in two mutually perpendicular planes and a quarter a size 3D model of piston solidification are presented. At the end of the paper, an overall evaluation of the thermal so-lidification of the cast piston depending on the solidification time is performed. The results of the numerical solution show that the solidification process begins at 2.5 minutes after casting and ends at 5 minutes. Subse-quently, only the piston and the metal mould itself are cooled.

This paper highlights the findings of multi-material application in 3D printed specimens. The work presents experimental results of multi-material, and multi-color-based 3D printed specimens by a multi-extrusion printer developed at the laboratory. It aimed to determine the bonding properties between the layers of various materials indicated with different colors. The samples were printed across multiple infill models and tested in the tensile and compression machine. The specimens were created with 10%, 25%, and 100% infill having single and dual colors material. Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), and Flex materials were used for printing various specimens with various colors. The layers were printed synchronously. The filaments were changed according to the predetermined algorithm. The experimental results showed that the mechanical properties of single, dual, and triple mate-rial specimens differed according to the reinforcement strategy. In addition, the mechanical property of the same material with different colors was identical.

The atomic force microscopy is method used to obtain surface properties of various materials, includ-ing surface morphology, local magnetization, conductivity and mechanical properties. In this work the atomic force microscope was used to investigate properties of rubber compounds. Three samples made of different rubber compounds that varied in filler content were studied in order to determinate their homogeneity and ratios of their Young’s moduli. Images of their surface topography were ob-tained and then on each sample five places were chosen where spectroscopic curves representing force – distance dependence were scanned. Parts of these curves from which Young’s modulus can be determined were approximated by linear functions and their slope was calculated. Slope values close to each other suggest similar values of Young’s modulus. By their comparison it was determined whether even distribution of ingredients in rubber compound can be assumed and thus the blending process to produce these compounds can be considered sufficient.

This paper deals with the use of lean manufacturing methods to streamline the welding line in the au-tomotive industry. The automotive industry is constantly developing and innovating its production envi-ronments and technology because of growing competition on the market and customer demands. Cur-rent trends of car makers include pressure to reduce costs and increase production efficiency. With the commencement of new technologies, the production lines began to innovate and the production cycle began to constantly accelerate. The paper deals with the reconstruction of the welding line, which produces parts for the rear axle of a compact SUV. The case study aims to identify bottlenecks and set innovation plans and their evaluation in possible implementation. In the paper, lean manufacturing methods are applied in order to deter-mine the ideal solution for ensuring the quality and ensuring the efficiency of the production line, lead-ing to cost reduction. Through these innovations and modernizations, the company will be heading for digitalisation that changes the core of the industry.

The article presents the results of experimental research on creating the mobile continuous earthmoving machin-ery. Methods for performing field experimental studies and measuring equipment used are described. The article shows the data of experimental research, their analysis, the determination of physical nature of changes in exter-nal load characteristics of the machinery operating equipment. The conducted experimental studies of modern mobile earthmoving machinery enabled to establish its technical capabilities, the characteristics of the power load of the operating equipment when developing the soil. It also enabled to determine the ways and directions for mod-ernizing the operating equipment of machinery. One of the ways is to optimize technological combination of soil cutting, displacement of the developed soil to the unloading area and unloading of the actuator. The research per-formed and the results obtained have enabled to experimentally confirm the effectiveness of the technical pro-posals to create the design of the chain and bar actuators with impulse soil unloading intensifiers for trenchers implemented in the industry.

Taking the discrete degree of bearing raceway grinding surface integrity as the research object, the orthogonal test based on the wheel speed, workpiece speed and grinding depth is designed. The residual stress, retained austenite, hardness, grinding modified layer thickness and roughness of the raceway after grinding test were measured, and the mean value and standard deviation of these indexes were calculated. The results show that the standard deviation of residual stress and roughness decreases with the increase of wheel speed, and the standard deviation of retained austenite, hardness and grinding modified layer thickness keeps stable. Finally, the optimal grinding parameters considering the scatter of surface integrity are selected.

The work is focused on comparison of ballistic efficiency of homogeneous laminates consisting of one type of prepreg based on aramid or UHMWPE and ballistic efficiency of hybrid laminates consisting of combitation of chosen prepregs layered in different order. For preparation of hybrid laminates the two types of aramid prepregs and two types of UHMWPE prepregs were chosen. The laminates were subjected to ballistic testing by fragment simulating projectile FSP G5 and their ballistic efficiency was evaluated by determination of ballistic limit V50. For more complex assessment of tested laminates with regard to ballistic efficiency and also their areal weight, the ballistic weight coefficient K, which is defined by quotient of V50 and areal weight, was determined for each laninate and then compared. Besides the ballistic efficiency the coherence of laminate layers after pressing and after shooting was also observed.

In the performed experiment, changes in the microstructure of steels S265 and X6CrNiTi18-10 due to their chemical-thermal treatment by boriding were studied. The boriding process was performed in a Durborid boriding powder at 900 0C. During this process, surface layers of Fe-B borides were formed in both analyzed sorts of steels. The layers differed in their morphology and composition due to the different degree of alloying of the matrix of analyzed steels by additive elements. The formed Fe-B layers showed high adhesive and cohesive resistance in both materials. Due to changes in the micro-structure of S265 steel, especially due to significant coarsening of the original grain of its matrix, its resistance to tribological abrasion after the boriding process decreased. The opposite effect was ob-served for X6CrNiTi18-10 steels. As a result of boriding, both analyzed materials changed their corro-sion resistance.