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An important trend today is the continual improvement of product quality with the objective of increased customer satisfaction, but also leading to more effective cost reduction management. Effective quality management in a company also enables increasing production productivity thanks to the increasing amount of top-quality products made and the consequent minimalization of repairs of non-conforming workpieces. This contribution deals with one of the important tools for ensuring quality in the production process using the FMEA (Failure Mode and Effect Analysis) method used in the production of roller bearings for the automobile industry.

Vibrational properties of road vehicile are ussually evaluated according to two criterions, i. e. in terms of comfort for passengers and in terms of drive safety and roadway load. The topic of this article is focused on evaluation of passenger's ride comfort of a three-wheeled road vehicle. From the ride comfort point of view vertical vibration is decisive. Vertical vibration is given by obtained accelerations in given position on an assessed vehicle when it is driving on a road with various surface qualities within required time intervals. In the vehicle's design phase its vibrational properties are detected and evaluated by means of simulation computations on a virtual model. In our research we have assessed ride comfort of the three-wheeled vehicle, which were designed in our workplace. For purposes of dynamic analyses we have used multibody approach using Simpack software. The objective of this work is verification of the relevance of the current mounted suspension system for the greater driving speeds range of the three-wheeled vehicle and for different road qualities.

This contribution is divided into two sections. The first one deals with identifying the cause of fracture in a ring, which fractured after weld surfacing. Optical and scanning electron microscopy and hardness testing were employed. Chemical composition was determined using the GDOES and EDX methods. Although weld surfacing has led to fracture in the base material, the actual problem was in the inadequate microstructure of the base material. Microscopic analysis revealed that it was heterogeneous. It contained distinctive segregation bands with bands of complex carbides and pearlite colonies, which are undesirable. The microstructure of this steel should be fully austenitic. In order to remove the heterogeneities, solution annealing was proposed and carried out successfully. The second section of this paper explores the options for revealing the microstructure of Hadfield steel. Etching reagents from the literature and authors' experience were put to test.

The combustion engine is a very widespread energy source for many machines and devices. Diesel, gasoline, LPG, CNG, as well as many biofuels such as ethanol, butanol, etc. are used as propellants at the present time. During the running of the internal combustion engine, some fuels penetrate into the crankcase and degrade the engine oil. This potentially reduces the lubricating ability of the oil and changes its degradation process. Submitted paper follows possible changes in lubricating capabilities of oil used in engines with specific fuels: n-butanol, LPG and diesel. Different type of fuel used in combination with an inappropriate operating mode might have a significant influence on the oil and consequently on the engine wear (monitored by a laser particle analyzer). This paper also deals with presence of various types of particles in the engine oil. Results demonstrate proceeding changes noticed in oil and also how was the degradation process effected.

Fast control coil is one of the most important components for EAST device to control the vertical stability of plasma. However, once the heating power of EAST is updated to 36 MW, fast control coil doesn't adapt to the new operation state and couldn't provide effective control for plasma vertical instability. Thus, insulation material with ITER-like magnesium oxide is developed to withstand high radiation and the coil position is also relocated to obtain more effective instability control. Given the relocation of fast control coil, electromagnetic load acting on coil-self and feeders are calculated based on elliptical integral and Ampere force law. The electromagnetic load as volumetric force is interpolated into the finite element analysis model to analyze the stress state on fast control coil. Finally, the design-by-analysis method is adopted to evaluate whether the stress could satisfy the specified acceptance criteria. The study will provide theoretical reference for the update of fast control coil from the perspective of electromagnetic load.

This work aimed to characterise microstructure and mechanical properties of polymer composite samples. The main task was to adapt the well-known techniques of metallography (i.e. sample preparation and microscopic examination) to documentation of multi-component polymer materials and to optimize the methods of light and electron microscopy for this particular purpose. There were several issues (e.g. low melting point, absence of electrical conductivity), which made the process different from metal samples preparation and observation and which needed to be addressed. Various mounting resins were tested for the samples to find the suitable one, then the process of grinding and polishing was optimized and finally the microstructure was documented using light and scanning electron microscopy (SEM). Samples in the undeformed state were examined as well as the samples subjected to tensile test at different temperatures. Prior to the microscopic observations the material was analysed using methods of thermal analysis (TG A, DSC) and infrared spectroscopy (FT-IR). The tensile tests were employed not only to determine the mechanical properties but also to obtain deformed samples for further microscopic observation.

The article deals with geopolymer binder system for core production, especially by dehydration technology and comparison with PUR cold box amin technology. A sodium-potassium type of geopolymer binder is the subject of the research. The goal of the article is the core production and observing of technological properties, storing cores, usage of refractory coating evaluating of properties during the pouring and decoring of casting. The main target of the experiment is casting quality. It was stated that the final surfaces are much more better than PUR cold box amin technology and the internal casting quality is the same, it means without inadmissible internal defects. Worse decoring times were observed. It has been confirmed, that neither emissions, fumes nor unpleasant odours are generated during the production procedure nor during pouring.

This work is devoted to description of microstructure of bulk Al-Fe-Mm-Si-Mg alloys and their thermal stability. The alloy was prepared at different cooling rates (600, 1000 and 1400 RPM) during melt spinning process and sintered at the same conditions by SPS. The aim of this work was to prove if change in melt spinning conditions influence the behaviour of bulk material. It was proven that independently on cooling rate precipitation occurs during sintering process. All materials exhibited heterogenous microstructure composed of fine and coarse areas - residue of melt spinning process. During annealing of bulk materials prepared by powder metallurgy, no precipitation of new phase was observed. It is an evidence that precipitation mechanism of self-healing is not possible for these alloys.

Laboratory fatigue testing is an important part of the fatigue design of machine components that are supposed to work under cyclic loading. These tests are used to confirm whether the tested component matches the required fatigue life and they also serve as a verification of the numerical calculations. This paper describes a fatigue life testing of a welded steel construction. The testing was carried out in the Regional Technological Institute (RTI) using an electro-hydraulic loading system, which allows realization of the tests simulating a real service. An integral part of the fatigue tests is a pre-scheduled inspection of the crack initiation and propagation. The tested construction was checked using non-destructive magnetic particle testing before the fatigue test and also during and after the performed test. Some cracks were observed, especially in the weld area. The biggest crack had the length of approximately 40 cm. This crack was cut out and underwent detailed metallographic and fractographic analysis to estimate the effect of material purity and quality of the weld on the fracture.

The use of cutting fluid should positively influence on the quality of the machined surfaces and durability of cutting tools. However, during the machining the oil from the hydraulic system of the machine often gets into the cutting fluid, which can alter the properties of the cutting fluid. In scientific literature there is no information about the effect of the hydraulic oil entering the cutting fluid on the tool life and roughness in turning. In this regard, at the laboratory of the Department of Machining and Assembly of the Technical University of Liberec, there has been conducted a study to ascertain the effects of hydraulic oil getting into different types of cutting fluids during the turning of stainless steel.

The paper deals with methodology of prediction of adhesive bonded joints strength. Problematics of adhesive bonded joints is a very complex task. There are several different (different precision and different complexity) mathematical models of adhesive bonded joints, which attempts to describe the real behavior of adhesive and adhesive bonded joints during load as accurately as possible. This article presents a comprehensive overview of what to take into account and how to proceed with designing/controlling the strength of adhesive bonded joints. Mathematical models are supplemented by material data from experimental tests. The proposed methodology takes into account both adhesive and cohesive properties (material of bonded parts, surface treatment of bonded material, type of adhesive, thickness of adhesive, bonding technology, loading modes etc.). Methodology "how to proceed" is described in detail and is complemented with a flowchart.

Fisheye contact pair is an important component of board level interconnection products wide range of applications. However, insertion and withdrawal force have great influence on the contact deformation due to their small size and complex structure. In this paper to the fisheye contact pairs of interconnection products as the research object, the main parameters were analyzed which could affect the contact deformation of fisheye structure, and factor analysis of them were performed. And three relatively more significant factors were extracted. The simulation based on Response Surface Methodology (RSM) is designed, And the experimental data was conducted regression fitting, getting the second regression model. The established quadratic regression model was analyzed based on MATLAB and the response of various factors on the insertion and withdrawal force, then the optimized parameter model of fisheye structure was obtained. The research shows that the quadratic regression model based on response surface methodology fitting accuracy was high and there were good practical value about it.

Although 3D printing offers many advantages over casting, it can alter the corrosion behaviour of processed metals and alloys. The corrosion behaviour is related primarily to the microstructure, which is very fine and heterogeneous in 3D printed metals due to very high cooling rates and the additive way of manufacture layer by layer. Therefore, we carried out corrosion tests according to the Audi internal standard to demonstrate how the 3D printing process influenced the corrosion behaviour of the AlSi9Cu3Fe alloy prepared by selective laser melting compared to a conventional casting. Corrosion rates were determined from mass losses and corrosion attacks were documented microscopically. Compared to the cast material, the corrosion rate was increased by ~ 60 % after 3D printing. Related to the microstructural heterogeneity and anisotropy, an uneven attack was observed on different sides of the tested samples.

In this work, the effect of heating rate on the reaction temperatures in Ti-20 wt. % Al powder mixture subjected to reactive sintering process were studied and microstructure, phase composition and porosity of the reaction products were described. This system was studied because the alloys based on Ti-Al intermetallics are modern high-temperature materials and their production by common metallurgical routes is problematic. Reactive sintering could potentially replace currently used method - melt metallurgy. However, many phases form during this process and some of them are undesired. For this reason, it is necessary to describe the temperatures and other reaction conditions of their formation. One of these parameters is a heating rate. The heating rate affects reaction temperatures, phase composition as well as porosity significantly. Therefore, various heating rates were tested and the reaction temperatures were determined. The heating was recorded by optical pyrometer and one exothermic reaction was observed. It was found that this reaction is associated mainly with the formation of Ti3Al phase. Further, it was revealed that porosity decreased with increasing heating rate. This work offers data important for thermodynamic calculation and description of intermetallic phases formation during reactive sintering process.

The main aim of this article is to show the possibilities of using tram windscreen impact tests in the analysis of human-machine accidents. Empirical experience shows that these accidents especially affect the head, which is at the same time one of the most vulnerable parts of the human body. Windscreen safety testing follows ECE standards and, inter alia, involves collisions with a headform. With regards to numerical simulations, however, it is essential to be able to determine the material characteristics of windscreens. Here it seems to be advantageous in terms of validity, reliability and the economic cost of using collisions with a rigid body where only the glass absorbs all of the kinetic collision energy. The outcome of these tests is a waveform of the cont act force's magnitude as a function of deformation in the direction the force acts. Along with the time course of acceleration of the bumper and its kinetic energy on impact, this information can serve as boundary conditions to verify mathematical models.

Detonation is a specific type of a rapid exothermic reaction, which always involves a detonation wave (in the explosive) and the shock wave (in the environment). Modelling of the pressure wave falls in the fluid flow and interference with obstacles in the flow. The purpose of this paper is to development of simulation model based on the finite element method (FEM) for shock wave propagation in air form the explosion of a spherical charge from TriNitroToluene (TNT) material. The air is the classical ideal gas and explosive material TNT is defined using Jones-Wilkins-Lee (JWL) equation. The computational model is 2D-dimensional model with four node axisymmetric elements. The effect of the explosion on the pressure distribution in the air and rigid surface (ground) is investigated. Numerical solution of the dynamic response was performed using commercial FEM software ADINA.

Aluminium roofing is used for low weight, good strength and weather resistance, easy handling and assembly, for various roofs of industrial and agricultural buildings, residential and family houses, holiday homes, garages and various shelters. Important is very long life, relatively low price and the possibility to choose the colour design according to your taste. The basic form is a natural unpainted finish, which can be used because the aluminium roofing material is not subject to corrosion and is chemically stable. The aim of this research is to verify a suitable method of measuring the colour of aluminium roofing and to determine the basic characteristic values of the most common colours of aluminium roofing sheets. The identification by the CIELAB system makes it possible to characterize the suitability of roofing sheets in terms of reducing the heat gains of the roof structure, thus complementing this very practical information to the RAL colour marking system. This leads to a reduction of the cooling demand of air of the building in the summer. In terms of colour measurement and evaluation, the classical method according to the CIELAB system is where the colour attributes lightness (L-value), redness (a-value) and yellowness (b-value). These values may include the effect of surface gloss (SCI values) or exclusion (SCE values).

Hardness tests enable to determine one of the main mechanical properties of the material, namely hardness. For hardness testing, it is possible to use either conventional desk hardness testers or the currently increasingly used portable hardness testers. The paper is focused on determination of the accuracy and reliability of static (desk) and dynamic (portable) hardness testers. The paper deals with the measurement of hardness of calibration hardness plates by 4 different methods (Brinell, Vickers, Rockwell and Leeb) with using 5 different hardness testers (3 desk and 2 portable). The hardness values measured by the different hardness testers were compared to the reference hardness listed in the calibration hardness plates and consequently, the accuracy of these measurements was evaluated. The aim of the work has been to determine the accuracy and reliability of portable hardness testers in comparison with desk hardness testers.

The heat treatment of the heat-treatable aluminium alloy forgings includes cooling from the solutionising temperature. After heat treatment, residual stresses remain in the forging, which are due to temperature gradients during cooling. The effect of these residual stresses on the forging properties can be significantly influenced by other technological operations, including artificial aging, machining, and surface treatments. The influence of the surrounding environment can also play an important role. Because in connection with the residual stresses after heat treatment we often encounter cracks in forgings, this paper is devoted to an overview of factors that influence cracks. The typical examples of damaged forgings are discussed and explained the circumstances that caused cracks under the influence of residual stresses.

This work deals with the construction design and manufacturing of a cylinder liner which is used in a Jawa 50 motorcycle in order to increase the performance characteristics. The liner is pressed in the aluminium cylinder case with ribs so together it makes a two-stroke motorcycle cylinder. The first step was to build an analysis of the technical design of the original motorcycle cylinder to detect any restrictive parameters for the modifications, especially of the cylinder liner, so the motorcycle can be used for racing. As well as the construction design of the liner, the work deals with the clamping and manufacturing of this part too. The CNC code was written using SolidCAM software. Then the liner was manufactured in a turning-milling centre. The purpose of this work is to produce a liner so that it forms a racing motorcycle cylinder together with the aluminium case with the ribs. The basis of this project is the correctness of the construction design and the accuracy in manufacturing so that the engine can achieve the demanded parameters with respect to usability, engine cooling, gear setup, engine life and the other restrictive parameters.

The article deals about modelling, dynamic analysis and optimization of stiffness and damping parameters of the main suspension of the Škoda 21Tr trolleybus. The trolleybus is excited by a ride on a rough road modelled using the Shinozuka method with the specified spectral power density. After examining the impact of tire stiffness and damping on the effective values of driving comfort characteristics, dynamic tire-to-road forces, and relative displacements between sprung and unsprang mass, the effect of spring stiffness and damping of dampers in main suspension are investigated. After selecting appropriate optimization parameters, the stiffness and damping parameters of the main suspension are optimized using the MATLAB Optimization Toolbox. The objective function is the sum of the effective values of the suspension mass acceleration and its angular acceleration. The results are the improved driving comfort without increasing the dynamic forces between the tires and the road and the relative displacements between the sprung and unsprung masses.

Main goal of this study is to describe and design manufacturing system which is using Additive manufacturing technology for production of semi-finished products and conventional machining technology for finishing operations, then demonstrate requirements of such production on simulation model on production planning and then analyze and summarize the outputs of the production model. The model is made with aid of modern Digital Factory tools. The main purpose of the model is to provide a complex tool for this study in order to analyze and optimize the fictive production system in needed range and complexity. The topic of Rapid Prototyping and Additive manufacturing technologies is very recent topic in industry. But still, there are only few examples of production systems, which are really using Rapid Prototyping technologies as a part of the production or production line. The advantage of these technologies is their versatility, but on the other hand, as a part of production system, they can have different demands on for example production planning, area consumption or maintenance, that can affect whole production system.

The principle of vibrodiagnostics lies in the appropriate measuring and analysis of mechanical vibrations of machinery and constructions in industrial and laboratory environment.
The aim of this paper is to perform diagnostic measurements on the most essential parts (spindles) of machinery devices Semico VCM 1000. Measurements were carried out by means of portable vibrodiagnostic measuring device Adash A4900 vibrio M. Vibrodiagnostic itself was realized as a walk-monitoring of machinery state according to corresponding technical standard ISO 10816-3:2009, and of limit values, which took place at regular intervals in the selected organization.

The article describes usage of the CRAFT method and its influence on the optimization of flow logistics. The method helps to reduce the cost of basic material flow determination in production, assembly of production units, material handling, storage of individual parts and the transport of finished products. By using the method, long traffic routes, unproductive times and warehouse inventory that unnecessarily increase our costs were removed. In today's competitive environment, it is necessary to improve continuously all processes not only in production, and this method enables us to effectively achieve defined business goals.

This paper deals with the causes of failure of total hip replacement. Hip joint replacement is one of the most frequently used surgical procedures worldwide. More than 200,000 surgeries are performed only in Europe each year, following early attempts by John Charnley. Currently, more than 340 of the total 4431 implants per year are reoperated in Slovakia. Despite the excellent properties of the titanium alloy, endoprosthesis often fails and the hip replacement is necessary. Common causes are overloading and cracking, static or dynamic. Other causes of failure include injury, implantation failure, manufacturing inaccuracies, and non-compliance with the manufacturing process.

Despite the fact that Titanium alloys are frequently used in medicine, aviation industry and also in machine manufacture due to their strength and resistance against external influences. Moreover, their innovation to obtain better and more suitable parameters still proceeds. Regarding their mechanical properties, they are considerably less machinable which affects surface integrity of a machined area. That is why a proper selection of a machine tool and cutting conditions are extremely important. This paper deals with a finishing grinding process of the material VT9 by means of specific grinding wheels 5TG and DIA under specified cutting conditions. Based on experimental verifications it can be defined which grinding Wheel is more suitable in specific conditions with an impact on integrity of the ground surface. From the standpoint of grinding parameters such as surface roughness, thermal impact and acting of cutting forces as well as arising residual stress in the surface layer are key for surface integrity.

The article deals with the measurement of conveyor belt noise and vibration. The conveyor belt was supported on six rollers fixed on three plates of stand, return and drive drum. These six rollers were produced in two sets (convectional tube and accurate tube). Rollers were driven by a rubber belt. The noise was measured and evaluated on both sides of the conveyor. Vibration of the conveyor was measured at four locations of the conveyor construction. All measurements were performed in an unloaded condition. In conclusion of the article is a summary and evaluation of all measurements. The vibration of the conveyor is comparable in both cases, however, the rollers from accuracy tube excite the construction less, and this results in a lower total noise. By comparing the acceleration to the dominant frequency, it is obvious that the noise and the vibration of the belt conveyor construction were reduced by using rollers from accuracy tube

The goal of the proposed methodology is to manage and evaluate investments across the portfolio of projects in the company, with extra focus on selecting engineering projects into the portfolio. In order to design an objective methodology, several analyses were conducted to verify a general validity of the methodology. The starting point is using methods which allow a high degree of flexibility in solving problems. The ANP method is suitable for the determination of priorities in network systems with different types of dependencies between the elements of the system. The DEMATEL method is used in this methodology to formulate the structure of relationships between the criteria of the system and obtain the criteria importance in the system. All calculations were carried out using the MAXIMA and Super Decisions software. The proposed methodology has been verified on a case study using real-life data supplied by the participating company. There were used methods of decision making, especially methods of operations research, linear programming and team expert selection methods.

An approach to increasing the efficiency of the diamond grinding of hard-working materials is shown. A well-founded choice of characteristics of the diamond-bearing layer of the tool can be made through analyzing the results of 3D modeling of the processes of formation and operation of the diamond-bearing layer and stresses upon it. Diamond wheels formed on porous ceramic binders are investigated and discussed.

This article deals with the evaluation of the change of selected 2D structure parameters of the grinded surfaces before and after application of plasma nitridation. Changes in parameters were analyzed on 30CrMoV9 steel samples which were ground to Ra ≈ 0.03 and then plasma nitrided in a standard nitriding atmosphere. An absolute method was used to evaluate the surfaces. Measurements were performed on a profilometer CLI 1000. The parameters comprehensively describing the surface structure were subjected by analyzes, namely the height, length, shape parameters and parameters of the material ratio. After plasma nitriding, almost all selected surface structure parameters have been increased. Higher values of the monitored parameters have an influence on the increase of friction and wear and negatively affect the running-up properties of nitrided components.