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The topic of the article is to compare the mechanical properties and define the differences in the degra-dation process for anticorrosive glass fibres type AR and for glass fibres type E after influence of the alkaline environment in the geopolymer composite. The ongoing reactions between glass fibres and al-kaline environment lead to the dissolution and slowly decomposition of the fibres and consequently to the loss of the mechanical properties of the composite. Corrosion of glass fibres is characterized by weight loss, change of fibre diameter, reduction of mechanical properties and formation of mineral in-crustations on the surface of the fibre, which gradually leads to the formation of a continuous corrosion coating so called corrosion shell. Scanning electron microscopy was used to monitor the morphology of the fiber surface, and image analysis methods were used to evaluate morphological changes. Tests of mechanical properties (fibers - tensile test, composite materials - three-point bending and Charpy test) were used to confirm ongoing degradation processes due to the long-term influence of the alkaline envi-ronment on both types of glass fibers.

A four factors and three levels orthogonal milling force (MF) test is designed, which qualitatively obtains the influence of four factors, namely workpiece material, workpiece diameter, milling speed and feed per tooth, on MF of the new cold saw blade milling cutter (NCSBMC), then further verifies the reliability of test data with simulation analysis of MF. The multiple linear regression analysis and deep neural network (DNN) are used to accurately fit and predict the magnitude of MF in three directions of NCSBMC, taking into account the influence of workpiece material factors on MF. Compared with the results of empirical formula, DNN has higher prediction accuracy. The research results provide theoretical guidance for the optimization of milling parameters in actual machining process.

Multilayer synthetic leather-like textiles are traditionally manufactured by using dimethylformamide as a diluent via polymeric polyurethane coating and coagulation processes. Unfortunately, this process has a strong environ-mental impact since it encompass a complex and polluting grinding process to separate dimethylformamide from water. Furthermore, this compound was proved harmful for both environment and textile practitioners’ health. The aim of this work is to improve the state of the art in the production of leather-like fabrics through the devel-opment of an innovative process of coagulation of polyurethane in aqueous solution to replace the current highly polluting process that involves the use of dimethylformamide. The coagulation is obtained by means of a IR ther-mal fixing thus resulting in a completely eco compatible manufacturing process. The obtained quality of the man-ufactured synthetic leather, tested according to textile standards, is comparable to the one obtained by means of conventional processes.

With the rapid development of science and technology, the means of industrial production have become more diversified and intelligent, and the development of new means of industrial production has become an increasingly important research topic. Therefore, the automatic assembly technology was studied taking machine vision system as the main research subject in this study. An automated assembly model of industrial technology based on machine vision recognition was established, parameters such as the part positioning parameter, assembly time, the number of parts wrongly assembled and the number of parts missing and the qualification rate of assembly were obtained, and the corresponding experimental conclusions were obtained. Moreover it was compared with the traditional manual assembly technology, and it was found that the automatic assembly technology based on machine vision recognition had better performance and more remarkable experimental results compared with the traditional manual assembly technology, and the traditional manual assembly technology needed continuous modification and optimization. This work provides a new route for automatic assembly technology in industrial technology.

The article describes problems of welding heterogeneous welds be specific of heat resistant steel X15CrNiSi20-25 with cobalt alloy Stellite 6. Heterogeneous welds are produced by GTAW (141 according to standard EN ISO 4063) welding method. The major goals of the experiment were performing preliminary welding specifications (pWPS) for a specific welded part. Further was necessary for this weldment set parameters on mechanical testing.

In this work the influence of material type and sample fill density was evaluated. One PLA material was tested. Test specimens having different fill structure and density were printed from this material. Full honeycomb and gyroid shapes were used for the fill structure. The specimens had four different fill percentages for each structure: 10%, 25%, 50% and 75%. These bodies were compared to samples that were printed with 100% fill. Tensile test was performed on printed test pieces. The Zwick / Roell Z100 was used for testing and the surface hardness of the test specimens was measured by the Shore D method on a DIGI-Test II hardness tester. Fracture surfaces were evaluated on an Olympus DSX 500 optodigital microscope. The results showed that the shape of the fill did not signifi-cantly affect the values obtained by the tensile test. The hardness measurement results showed a different hardness on the bottom surface that was in contact with the printing pad and the top printing surface. Fractographic analysis revealed different types of fracture surfaces related to the printed fill structure.

The assessment of porosity in aluminium casting is the main object to reach the required properties. The determination of amount, size, 3D morphology of casting defect by using a non-destructive (ND) meth-od, especially the computed tomography (CT), is important for assessment casting with complex internal areas that could not be inspected by conventional measurements without failure of the final products. The aim of this study is assessment of bars casted by gravity die casting in to the sand moulds with using the computed tomography. The size, amount and volume of casting defect were assessment by equipment Zeiss Metrotom and software Metrotom OS and VG studio MAX. The results show the influence of the shape of the moulds on the quality of the bars and thus the size, amount and volume of casting defects.

The laser welding method is one of the youngest but the most progressive welding methods. The advantages of laser welding include: simple automation combined with modern computer technolo-gy, very low heat input to the weld, high productivity, high welding accuracy and low noise during laser operation. In this work, the sample meltings were prepared in a protective atmosphere varying the welding parameters – laser power, welding speed, or focus position. A total of 12 samples were prepared this way. The aim was to evaluate the shape and depth of the melting of the material for selected values of parameters. Based on this metallographic evaluation, the optimal welding parame-ters were selected for a pair of austenitic stainless steel tubes (X2CrNi19-11 and X5CrNiMo17-12-2) for fiber laser welding. Macrostructure and microstructure evaluations, microhardness tests and tensile tests were performed on these welded samples.

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.

Cemented carbides belong to one of the most important groups of tool materials, whose percentage among all other materials used for cutting tools has reached about 50% in the global industry. Powder metallurgy methods have been used to produce cemented carbides, of which spark plasma sintering (SPS) is considered highly prospectiveThis paper presents the results of preliminary research concerning the effect of the fraction of the binder phase and sintering temperature on the microstructure, density, hardness and resistance to brittle fracture of cemented carbides produced by spark plasma sintering. The test materials were WC powder with a purity of min. 99.5% and Co powder with a purity of min. 99.8%. The obtained mixtures (WC-3Co, WC-6Co and WC-9Co) were sintered using the SPS method at 1300°C, 1350°C and 1400°C. The heating rate was 400°C/min. The pressing load was 80 MPa. Density measurements were carried out using the Archimedes method in accordance with PN-EN ISO 3369:2010, while hardness measurements, using the Vickers' method, were performed in accordance with PN-EN 23878:1996. Resistance to brittle fracture was determined based on the measurement of the length of cracks formed on the corners of the indentation. The observations of the microstructure and analysis of chemical composition were carried out using the scanning electron microscope. The phase composition of the obtained materials was determined by means of X-ray diffractometry.

The paper presents results of research under the effect of surface thermo-chemical treatment on the cor-rosion resistance of X6CrNiTi18-10 steel. The corrosion resistance of the surface layers of stainless steel obtained as a result of thermo-chemical treatment (boronizing process) was assessed using the method of progressive thinning, which consists in performing corrosion tests on deeper and deeper areas of the surface layer. This method allowed for the determination of changes in individual characteristic corro-sion parameters read from the potentiokinetic polarization curves and the determination of the depth profiles of these parameters. In the paper, results of tests of X6CrNiTi18-10 steel resistance to general corrosion, performed in acidified sulphate solutions (pH = 1) have been presented. The thickness of the surface layer was assessed on the basis of structural tests and changes in microhardness on the cross-section of the material. It has been found that the extremely high hardness of the boron layer was accompanied by deterioration of the corrosion resistance. The general corrosion rate of the surface layer is 3-4 times higher than the corrosion rate of the material core (substrate). The characteristics of the pas-sive state of steel are particularly worsened, which is manifested by an increase in the value of the critical passivation current, the minimum current in the passive range and by limiting the tendency to secondary passivation.

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.

Optimization is the process of finding the best possible solutions of a problem. It has been widely used in various areas especially in engineering problems. One of the common issues that is faced by some of manufacturers is finding drilling sequences of multiple holes. By drilling multiple holes with the least total path length, the manufacturer can save a lot of time and it can increase the productivity of the company. Thus, this study focuses on drilling path of multiple holes problem which has been solved by other researchers. This study uses the Bees Algorithm to find the best sequence of drilling holes (mini-mum total path length) and the results found are compared with the result of other algorithms. In addi-tion to results comparison with other algorithms, the results obtained are verified with simulation results using MasterCAM software. The results comparison shows that the Bees Algorithm achieved compara-ble performance compared to other algorithms.

This work discussed the corrosion behavior of the internal surface of pipeline steel caused by the composition of petroleum products, particularly crude oil. Internal and external pipeline corrosion is the notable cause of pipeline failure in Malaysia’s oil and gas industry. However, internal corrosion is preferred to be concerned in this work because it involved one of the major corrosive media in the crude oil, such as sulfur content. This project aim is to find the sulfur concentration in the crude oil using Fourier transform infrared spectroscopy and atomic absorption spectroscopy. The corrosion rate, corrosion current and corrosion potential of the API 5L X65 grade carbon steel pipeline in different simulated H2SO4 solution concentrations were carried out using the Tafel extrapolation technique. The corrosion properties of the samples were morphologically measured by means of optical microscope, scanning electron microscope and energy dispersive X-ray analyses. The results showed that the corrosion rate of the pipeline steel significantly increased with the increasing H2SO4 concentrations. The corrosion products formed on the pipeline steel surfaces were mainly composed of iron sulfate, iron sulfide and iron oxide. These findings are crucial to understanding the corrosion behavior caused by the crude oil and should be further investigate with the other possible influence factors such as temperature and petroleum’s flowing velocity.

In the present study, local defects in deep groove ball bearings are studied as forward and inverse problems. To this end, the separation-integration method is applied for modeling the forward problem. It is assumed that the inner race of the rolling element is multi-DOF, while the outer race is deformable along the radial direction. Then the problem is modeled with concepts of the finite element method. The contact force for the rolling elements is described by the nonlinear Hertz contact deformation. Various surface defects originating from local deformations are introduced into the developed model. Since the outer ring can be coupled with the FE model of the housing, the developed bearing model is capable of considering the transmission path of the bearing housing. Then model parameters are modified to reach better performance in predicting local defects. Through translating the inverse problem into the comparison of the geometric distance, measured indicators are used in the defect detection process and the relative location and size of defects are predicted. Finally, the defect range is established to evaluate the fault severity. Obtained results demonstrate that the proposed method is effective and accurate in the studied cases.

The paper is focused on an analysis and optimization of the rotary draw benging process to eliminate bent tube ovality by modification of the pressure bar geometry. The bending process is realized on WafiosCNC bending machine. A tube that is bent for an automotive application is made of 34MnB5 steel. Currently, after tube bending process by an angle of 120°, an unacceptable ovality occurs. Therefore, it is necessary to improve the quality of production and thus prevent the formation of unacceptable ovality. In this case, the optimization of the pressure bar geometry is performed. For this reason, a numerical simulation using finite element method in ANSYS software is performed. Before the actual optimization, an accuracy of the simulation is verified by analysing of the current state and comparing it with simulation results.

In order to improve the transmission efficiency and the service life of ordinary cycloid gear, 5 kinds of new cycloid gears with variable cross section are devoleped based on the principles of traditional cycloid drive. These new cycloid gears include concave cycloid gear, drum cycloid gear, spherical cycloid gear, oblique cycloid gear and cone cycloid gear. The general mathematical equations of these new cycloid gears are obtained and the characteristics of these new cycloid gears in transmission applications are analyzed in detail. A new method on the end milling tooth profile surfaces of cycloid gear using ball end mill is proposed. 5 axis numerical control simulations of these cycloid gears are conducted and the tool paths of machining cycloid gear are obtained. 5 kinds of cycloid gear with variable section are machined on five-axis CNC machining center, which verifies the correctness of the NC program. The study will provide a new way of designing and machining cycloid gear.

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.

The aim of this paper is an analysis of the dependability of critical components of the John Deer 7530 tractor. For this analysis data was used from a database which contains maintenance data of 166 trac-tors during approx 9 years. The first part of this article is devoted to the selection of critical compo-nents based on number of failures of individual machine parts for a given period and their sales pric-es. The next part of article presents data for calculation dependability indicators which contains oper-ating times to failure and operating times without failure. Due to the large size of the data files of the individual components, the data are only given for one machine component. Furthermore, the meth-od of calculation of dependability indicators is described by parametric statistical methods according to ČSN EN 61649:2009 and mean time to operating failure. The results of the analysis are summa-rized in tables and graphs. The method in this article can be used to optimise the maintenance pro-gram.

The work is focused effect of different temperature nozzle in additive manufacturing process FFF (Fused Fila-ment Fabrication) technology for the most common materials (PLA, PETG and ABS). A standard specimen internal structure arranged ±45° in longitudinal print direction with 100% infill. For the exact testing are used no perimetres. The specimens were printed by minimal, middle and maximum nozzle tem-perature. Temperature range is given by the filament company. To ensure relevant testing materials from the same company in one colour were used. A printed specimens were testing by destructive testing method on tensile testing machine. For testing were made five specimens in one setting. Finally, were made 45 specimens for tensile testing.

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.

Presented article deals with designing of the novel technology for repairing of the defects in branch connections of the gas pipelines. Until now, defects of the branch connections could be repaired mainly by replacing of the damaged area, especially those allied with gas leakage. The most important requirement of new type of repairing technology is maximal allowable operational pressure, which has to be the same as for repaired pipeline. Dimensions of the split sleeve should be thus designed according to required pressure value. In the case of split sleeve for branch connections, dimensions were determined by the static analysis in ANSYS software. Designed sleeve was after manufacturing process subjected to pressure testing by standardised test to confirm requirements of the standards. Pressure test to destruction was performed in order to determine the weakest place of construction. Proposed repairing solution might lead to reducing of the costs for performing of the branch connections repairs.

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.

This experiment assesses the suitability of square-welding high strength steel using the deep penetra-tion welding method, RapidWeld. The aim of this method suitability assessment was to compare the final material properties of three welds, welded accordingly to identical welding procedures. High strength, ultra-fine-grain steel S1100QL (XABO 1100) was used as a parent metal. The suitability con-firmation was based on the achievement of requested mechanical properties of ISO 15614-1 and mo-bile crane manufactures standards. The hardness, strength properties and impact energy measure-ment and evaluatioon of the joint was performed during the experiment. The joint was welded re-peatedly with the use of the same welding parameters for the confirmation of process stability. The achieved mechanical properties fulfill all the requirements. The hardness value deviation is caused by different properties in the heat affected zone. The root cause of the impact energy deviaton was not fully investigated, but the minimal measured values are above requirement. The deviation of the strength characteristics is mininal. The performed experiment has confirmed that the selected weld-ing method is suitable to ensure that the requested material properties of welded high strength, ultra-fine-grained steel are achieved.

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.

In this paper, innovative resistance element welding (REW) technology for joining galvanized steel sheets to thermoplastics (PMMA) is introduced. The essence of the innovation is in the use of a special bimetallic joining element consisting of the core made of a Sn60Pb solder, and the sleeve made of a Cu tube. During resistance heating, the solder melts, thus allowing the formation of a metallurgical joint with galvanized steel sheet. Since Sn60Pb solder melting occurs at temperatures (from 183 to 190 °C) be-low the thermal decomposition temperature of most thermoplastics (for PMMA above 300 °C), there is no thermal destruction of the PMMA material around the joint. The mechanical fixation of the thermo-plastic material at the overlap joint is provided by the sleeve made of Cu tube which has a substantially higher strength than a Sn60Pb solder.

With the rapid development of modern manufacturing technology, people have higher and higher requirements for the quality of mechanical products, and the precision of machine tools for processing mechanical products has gradually increased. Therefore, the development of static pressure guides is particularly important for precision processing industries. The load on the guide rail has an important effect on the thickness of the oil film, and the stability of the oil film thickness directly determines the accuracy of processing. In order to obtain the best control method for the thickness of the oil film, the dimensions of the hydrostatic guide rails and the three-dimensional model of the guide rails were designed and calculated in this paper, and the fuel supply method of the guide rails was determined. The simulation model of the oil film was established and imported from the AMESim software into the FLUENT software to obtain the pressure, velocity, and temperature distribution maps of the oil film. And the pressure distribution data was processed after summarizing. Combined with the relevant mathematical models, the mathematical model of the oil film thickness was finally obtained. Then the Simulink software was used to analyze and the PID control was introduced for comparative analysis. The DOB anti-interference control theory was introduced, and the anti-interference control algorithm was improved. The anti-interference algorithm adapted to the oil film thickness control complete the programming of the modules of the interference controller. The anti-interference control section was created in the Simulink software, and the system of the DOB module was finally completed after packaging. In order to verify the method in t his paper, a static pressure rail test bench was set up, and relevant detection tests were completed. The results of the above studies showed that the control performance was greatly improved after introducing the anti-interference algorithm adapted to the oil film control system.

Increasing the efficiency of cutting operations while fulfilling the required (expected) quality of the parts constantly requires a thorough knowledge of the chip removal process. This is especially justi-fied in the case of deviations from the usual (traditional) technological conditions or cutting data, both in terms of cutting theory and technique. This paper summarizes some of the results of a study of cutting force and cutting temperature in face milling. The technological analysis of face milling was performed by FEM simulation, which was compared and validated by measuring the cutting force. The chip removal of C45 rolled steel as a function of tool rotation was studied with two differ-ent depths of cut ap and feed rate fz so that at a constant nominal Ac cross section the ratios ap/fz were 0.1 and 10. The effect of the change of the cross-section and chip ratio is shown.

The current study investigates the influence of the dressing process of the vitrified bonded microcrystal alumina grinding wheel on the roughness of the machined surfaces in cylindrical grinding of Ti6Al4V alloy using different types of stationary diamond dressing tools. For the research, four types of dressers were selected, which differ from each other by number, size and location of diamond cutting elements. Each dresser has been tested at four different dressing feed values with the same dressing depth. Two sets of experiments were conducted to determine the tendency of grinded parts roughness parameters change depending on the dressing feed for each type of diamond dressing tool at two values of grinding feed. A comparative analysis was carried out to show the dressing feed influence and the effect of the diamond dresser type select on the roughness parameters of the grinded surfaces.

The given paper deals with the wear of the tensioner which is produced from aluminium alloy and used of the motorcycle timing chain. This component was made due to the unavailability on the spare parts market. The AlMgSi1 alloy was chosen for this purpose, taking into account the requirements for producing of the tensioner. After production, the tensioner was put into operation where its functionality was regularly controlled. The suitability of the selected material was checked after the tensioner was removed. Possible damages and structural changes in the material were assessed using a scanning thermoemission electron microscope. Detection of the chemical composition of foreign particles trapped on the surface of the tensioner from engine oil during the operation was performed by EDS analysis.