Žilinská univerzita v Žiline

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    Výskum hybridných hliníkových odliatkov s použitím penových jadier
    (University of Žilina, 2024) Medňanský, Martin; Brůna, Marek
    The paper focuses on the technological challenges posed by the production of experimental hybrid castings by overcasting technology. Theoretically, using this technology provides lower casting weight while maintaining positive mechanical properties and improves the energy absorption capability of the component. The effect of the pressure used during the foaming of the cores on the relative density of the metal foam component was experimentally evaluated. The challenge of the technology is the interface between the casting and the oxide coated core surface. Surface-treated cores were cast and their interfaces were observed microscopically. The experimental results showed a positive effect of the presence of AlPO4 in the interface to prevent the penetration of liquid metal into the pores of the foam core.
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    Hodnotenie vplyvu technologických parametrov na mikroštrutúru vysokotlakových odliatkov
    (Žilinská univerzita v Žiline, 2023) Medňanský, Martin; Brůna, Marek; Matejka, Marek
    A number of technological parameters influence the mechanical properties of a high pressure die casting. The aim of the presented paper was to perform microstructural analysis of AlSi9Cu3(Fe) alloy casting fabricated with high-pressure die casting (HPDC) technology. Several castings with varying casting parameter – maximum plunger speed vmax were cast. In pre-selected critical spots, the effect of vmax was observed on the shape and size of the structural components, where at lower vmax the eutectic Si shortened in length and thickened. EDS analysis determined found intermetallic phases to be α-Al(Fe,Mn,Cr)Si in the shape of a rhombic dodecahedron with sizes as small as 2 µm and Al2Cu being present in both modifications – oblong grains and globular ternary eutectic. There was no significant change in microhardness of α(Al) phase found, that would be caused by the varying vmax
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    Oxidické vrstvy a bifilmy v odliatkoch hliníkových zliatin
    (Žilinská univerzita v Žiline, 2023) Galčík, Marek; Brůna, Marek
    Surface of aluminium alloy melt is covered by an oxide layer when it is in contact with the surrounding atmosphere. When the oxide layer is retained on the surface of the melt it prevents the melt by hydrogen saturation. The oxide layer is harmful when it is submerged into the melt. The work focuses on the influence of the melt velocity on the bifilm formation, morphology of oxide layers and their influence on the porosity and filling the mold cavity.
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    Accompanying phenomena during casting of aluminium alloys
    (University of Žilina, 2023) Galčík, Marek; Brůna, Marek; Medňanský, Martin
    An oxide layer is formed on the surface of a molten aluminium alloy when it is exposed to the surrounding atmosphere. The oxide layer on the surface of the melt is not harmful. The problem occurs when it is entrained into the melt volume and solidifies in the casting. The paper deals with the formation of the oxide layer, its types and the formation of a double oxide layers.
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    Štruktúra hliníkových zliatin pre vysokotlakové odlievanie
    (University of Žilina, 2023) Medňanský, Martin; Brůna, Marek; Matejka, Marek
    The aim of the presented paper was to carry out a review of the internal structure of alloys used for high pressure die casting (HPDC) and to experimentally perform a structural analysis of AlSi9Cu3(Fe) alloy. Several castings with varying casting parameter – maximum plunger speed vmax were cast. In pre-selected critical locations, a change in porosity was observed with the change of the speed, and the casting samples with vmax = 2 and 3 m∙s-1 showed the lowest porosity. The effect of vmax was also observed on the shape and size of the structural components, where at higher vmax the eutectic Si grew in length and decreased in thickness. EDS analysis determined found intermetallic phases to be α-Al(Fe,Mn,Cr)Si in the shape of a rhombic dodecahedron with sizes as small as 2 µm and Al2Cu occurring in both modifications – oblong grains and globular ternary eutectic.
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    Technológ 3/2022
    (Žilinská univerzita v Žiline, 2022) Sýkorová, Martina; Bolibruchová, Dana; Bílik, Jozef; Sobota, Róbert; Šuba, Roland; Mojžiš, Milan; Litvaj, Ivan; Dižo, Ján; Blatnický, Miroslav; Ishchuk, Vadym; Molnár, Denis; Štaffenová, Katarína; Rakyta, Miroslav; Bubeník, Peter; Biňasová, Vladimíra; Kasajová, Marta; Tarbajovský, Pavol; Puškár, Michal; Абович Подригало, Михаил; Петрович Кравченко, Александр; Герлици, Юрай; Сергеевич Шеин, Виталий; Сергеевич Ткаченко, Александр; Александровна Кравченко, Екатерина; Kantoríková, Elena; Koňár, Radoslav; Matejka, Marek; Podprocká, Radka; Kostrzewski, Mariusz; Jerzy Nowak, Wojciech; Medňanský, Martin; Brůna, Marek
    Vplyv teploty precipitačného vytvrdzovania na vlastnosti zliatiny AlSi5Cu2Mg legovanej Zr || Seamless Tubes Manufacturing Processes Analysis || Decision-making process and knowledge management, knowledge management and skills || Nákladné prívesy za traktor - koncepčné usporiadanie a ich typy || Proces reverzného inžinierstva s využitím 3D laserového skenovania || Nákladné prívesy za traktor - špeciálne verzie a zvláštna výbava || Knowledge, knowledge management and innovations || Návrh modelu parného rušňa || Integrovaný systém pre redukciu emisií spaľovacích motorov || Technical preparation of production || О выборе мощности двигателя автомобиля на этапе проектирования || Vplyv tepelného spracovania na nástrojové ocele || Skúsenosti pri ultrazvukovom skúšaní zvarov v praxi || Hodnotenie tepelného zaťaženia vysokotlakovej formy pomocou numerickej simulácie || Rzeczy kilka o transporcie kolejowym ładunków w Japonii || Precipitačné vytvrdzovanie Al-Si-Cu-Mg zliatin || Numerické simulácie vplyvu technologických faktorov na štruktúru vysokotlakových odliatkov
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    Technológ 2/2022
    (Žilinská univerzita v Žiline, 2022) Mičietová, Anna; Minárik, Peter; Čilliková, Mária; Neslušan, Miroslav; Čapek, Jiří; Sivák, Samuel; Maláková, Silvia; Harachová, Daniela; Kulya, Juliy Martyn; Tomáš, Miroslav; Evin, Emil; Kantoríková, Elena; Moravec, Ján; Galčík, Marek; Brůna, Marek; Širanec, Lukáš; Bolibruchová, Dana; Bronček, Jozef; Drbúl, Mário; Konstantová, Viera; Kožienka, Lukáš; Koňár, Radoslav; Šutka, Jozef; Blatnický, Miroslav; Dižo, Ján; Molnár, Denis; Bubeník, Peter; Kolesnyk, Olha; Rakyta, Miroslav; Čapek, Juraj; Frátrik, Martin; Mičian, Miloš; Trško, Libor; Hirjak, Rastislav; Mišaneková, Viera; Chudíková, Dáša; Šimko, Radomír; Piroško, Martin; Jaremko, Matúš; Uhrík, Radoslav; Melo, Borislav; Málek, Miroslav; Mičian, Miloš; Derďák, Ján; Sikora, Eduard; Baba, Marcel; Kotora, Miroslav; Kamenský, Rastislav; Pobočíková, Ivana; Guldan, Vladimír; Sedliačková, Zuzana; Chupáč, Radoslav; Кравченко, Александр Петрович; Кравченко, Екатерина Александровна; Дижо, Ян Янович; Блатницкий, Мирослав Янович
    Abstract: This paper deals with surface integrity after shot peening of AlSi 304 under variable conditions expressed in term of shot-peening cycles and corresponding Almen intensities. Surface state is investigated from the point of view of surface topography, surface roughness and microhardness. Also phase transformation of paramagnetic austenite into strain induced martensite is investigated as well by the use of Barkhausen noise technique. It was found that the fraction of strain induced martensite grows with the number of shot-peening cycles and its extent penetrates deeper beneath the free surface. Furthermore, surface roughness decreases along with increasing number of cycles. Surface microcracking occurs after prolonged shot-peening cycles. Abstract: Paper was devoted to new methods coming to wide use in design engineering. These methods contained of topology optimization and generative design. Although topology optimization is practiced for some time, the generative design is its biggest contender. Both methods were described in a way of how they work and what methodology needs to be abided. At the end, a comparison between advantages and disadvantages as well was done, taking into account use of both of them in gear wheel body optimization. Abstract: The paper focuses on the manufacturability optimization of the of case made of aluminium by the rubber forming process. Al6016 aluminium was considered as the material for the cover and its constitutive equations were defined by Hill 48 and Hollomon models. The Mooney-Rivlin hyperelastic material model described the material properties of the rubber-made punch. Simulation model was built in Pam stamp software and the results were evaluated as well. The results were optimized in terms of thickness thinning and punch stroke, for two different rubber hardness. Abstract: The article describes the method of boriding sintered carbides type H1 (K10) and G1 (K20) and tool steel Cr-Mo-V. The aim of this work is to analyze the knowledge about boriding of steels with the focus on the technological assumptions of the use of boriding in the production process of forming tools in order to increase the resistance to friction, abrasive and adhesive wear. Interestingly, boriding is still an unconventional method of surface treatment. The presented work deals with the structural analysis of borided layers. Steel samples of 1.2365 material and sintered carbides H1 (K10), G1 (K20) borided with EKabor 2 powder were monitored. For the testing of metallographic samples, the methodology developed for the study of the microstructure of sintered carbides was developed. The monitored samples, borided at 900 °C for 240 min, obtained a uniform layer 5 μm thick. An increase in microhardness of more than 700 HVM was measured for carbide H1 (K10) and almost 1500 HVM for G1 (K20). The increase in hardness is due to the formation of dispersed cobalt borides Co2B and CoB. Abstract: Submitted paper aims to further analyse the possibilities of melt velocity reduction in the gating system. In this work was designed the naturally pressurized gating system. Proposed design appears to be a suitable solution for reoxidation processes reduction. Disadvantage of this system is that the melt velocity is supercritical, which leads to splashes of the melt when entering gates. Main focus of experimental part is to find a proper way to reduce the melt velocity, which will consequently decrease the reoxidation processes. For the purpose of the melt velocity reduction, labyrinth filters, flat filters and foam filters effect were investigated and visualized by simulation software ProCAST. Experimental casts were carried out, to be able to verify the results of the simulations. Mechanical properties and porosity evaluation was investigated on casted samples. Flat and foam filter appeared to be a suitable to melt velocity reduction and it was associated with increasing mechanical properties of castings. Construction with foam filter achieved the best results. Abstract: The aim of this paper was to analyze the impact of different zirconium addition (0.05; 0.10; 0.15 and 0.20 wt. % Zr) on selected properties of AlSi5Cu2Mg aluminum alloy. It is a new alloy for cylinder head castings and has only been used for a relatively short time. The specificity of this alloy is its chemical composition - specifically the low permitted Ti content, which makes it impossible to refine the grain structure of this alloy using standard Al-Ti-B grain refiners. The results of our research showed that increasing zirconium content had no effect on the increase in ultimate tensile strength, yield strength and hardness of as-cast samples. After T7 heat treatment, a more significant increase in UTS, YS and thermal conductivity occurred due to the precipitation of Cu- and Mg rich strengthening precipitates. Zirconium-rich intermetallic phases were observed in the shape of separate thick needles or as a cluster of two crossed thinner needles. These phases were not affected even after heat treatment, indicating their high thermal stability. Increasing the Zr content was accompanied by an increase in liquidus temperature and area fraction of porosity values. Abstract: International Standard EN ISO 22081 sets out rules for the definition and interpretation of general geometric specifications and general dimensional specifications according to Article 5.12 of ISO 8015: 2011). The general GPS specifications apply individually to each characteristic of a geometric element or to a relationship between geometric elements for which no individual GPS specification of the same type is defined. The general GPS specifications, which prescribe general dimensional and geometric tolerances, make it possible to simplify the indications and thus the reading of the drawing documentation, while at the same time facilitating the selection of tolerances. The new standard EN ISO 22081 replaces the standard ISO 2768 and gives rules for the application of the general geometric and general dimensional specification. Abstract: The paper deals with the limitations of testing ferromagnetic materials by the magnetic particle method. It focuses mainly on the influence of orientation and depth of materiál defects on the reliability of identification of surface and volume defects when using color and UV methods. The results obtained using unidirectional and alternating pole magnetization in manual control with a magnetic yoke are compared. Abstract: The article deals with the historical development and analysis of the current state of handling machines used in the entertainment industry. It points in particular to the material aspect, i.e. materials used for the production of amusement park equipment components. The article represents an important aspect that precedes the design of such a device, respecting the currently valid legislative requirements based on the standard STN EN 13814 so as to ensure protection against injuries or potentially dangerous situations (ejection, falling out, hitting, etc.). Abstract: The growing trend of using and processing big data brings space to study, analyze and understand the performance aspects of the monitored advanced technologies. In general, benchmarking is a well-known tool in the world of software systems that is commonly used to identify companies' strengths and weaknesses. The article presents the use of the benchmarking tool as a tool for evaluating the application of advanced technologies supporting the management of the production process. Abstract: The strength of fine-grained HSLA steels is mainly based on the grain boundary strengthening, which as the only strengthening mechanism allows the yield strength to increase without a decrease in ductility. Therefore, any change in grain size leads to irreversible changes in the properties of the material. Such changes also occur in the coarse-grain heat affected zone (CGHAZ) of welded joints, where there is an increase in austenitic grain size, which leads to a decrease in yield strength, or decrease of fatigue strength. The paper experimentally determines the growth kinetics of austenitic grain for S960MC steel. Based on the measured data, it will be possible to predict the grain growth kinetics in the CGHAZ and FGHAZ. The acquired knowledge will help to set the welding processes of fine-grained steels. The measured data will also provide a basis for numerical simulations of metallurgical processes in high-temperature HAZ during welding. Abstract: One of the basic requirements of the current industrial production is to extend the life time of thermal aggregates while taking into consideration the maximum economic effectiveness. The use of non-shaped refractory mixtures for manufacturing of monolithic linings represents a progressive trend that replaces traditional brick linings. Non-shaped materials enable to create linings of different shapes and sizes, their firing takes place at the consumer and their repair is much simpler. These aspects increase the productivity and save energy. The paper covers practical applications of castables from the production of the company RMS Košice s.r.o. in the foundry industry. Abstract: The article is a continuation of research dealing with the construction of entertainment facilities. The main goal of the authors is therefore to design such an entertainment device according to their own design. This goal was preceded by a historical overview of the development of transport and handling technology used in the entertainment industry. The current work aims to analyse the main components used in the construction of these devices such as nacelles, seats, restraints or drives and fasteners according to STN EN 13814 so that the design meets all requirements. Abstract: The paper is supplemented by a discussion of the results and in the end an evaluation of the experiments is made. The paper presents basic theoretical knowledge about the cutting process. The experimental part describes the cutting, forming and evaluation of the obtained cylindrical samples for rolling elements. Abstract: Residual stress plays an important role in welded structures, which are stressed not only by cyclic loading. The work deals with the creation of a butt weld joint made of HSLA steel S960MC with a thickness of 3 mm and its subsequent analysis for residual stresses. The result of the work is the evaluation of the residual stresses of the welded joint. Abstract: In addition to the mechanical properties, the formability and appearance after painting of the coated sheets depends on the surface texture. The surface roughness characteristics of the sheet, the mean arithmetic deviation Ra and the number of peaks per centimetre Pc, depend on the surface texture of the finishing rolls of the rolling mill, their wear and the removal on the rolling mill. This paper presents the results of an investigation of surface-finished sheet metal, the surface of which was textured by changing the electrodischarge texturing (EDT) parameters of the finishing rolls of a rolling mill. The optimization of current Ip, voltage Up, pulse duration POnT and pulse off time POffT on the target values of roughness RaT,FR and number of peaks PcT,FR of finishing rolls was carried out by response surface methodology (RSM). The obtained regression models describe with a high degree of accuracy the relationships between the input electrodischarge texturing parameters of the finishing rolls and the output texture characteristics RaT,FR and PcT,F Abstract: The issue of the conditions and suitability of the supply of glass to the dispenser head can be precisely solved only with the use of knowledge of fluid mechanics. The paper presents the used calculation methods of finite parameters and also makes their mutual comparison in terms of suitability of the solution. Abstract: In the hot metal and steel production the thermal equipment used for their production is essential with respect to the associated costs. The lining of torpedoes, blast oxygen furnaces, hot metal and steel ladles must withstand challenging manufacturing conditions. The working lining, that gets in contact with hot metal, wears out since it is affected by molten metal. The permanent lining on the other hand fulfills the safety and insulation function. The permanent lining is supposed to collect molten metal if the working lining is worn out and keep the metal temperature on the level of processing. When emptying a ladle, the lining protective layer (scab) is created if the temperature on the working lining surface is lower than the metal melting temperature. When designing the lining composition, the emphasis is given to material properties, as well as to its life time at the lowest costs per ton of steel. The paper evaluates permanent linings of metallurgical aggregates based on their thermal shock resistance and level of penetration into the brick volume. Abstract: The paper deals with an overview of selected additive technologies used in the automotive industry. The emphasis is mainly on technologies that use metal powders. Furthermore, the work focuses on machine improvements and also presents a possible breakthrough in series additive production thanks to new production systems. Abstract: The paper presents the application of one-way analysis of variance (ANOVA) and Tukey's HSD method of multiple comparison, which can be used in the experiment, which determined the effect of cutting speed on the perpendicularity deviation of the cutting surface when cutting stainless steel X5 Cr Ni 1810 using laser. The details and technological parameters of laser cutting steel are mentioned. Based on the results obtained using ANOVA and Tukey's HSD method, it can be argued that different cutting speeds have a statistically significant effect on the perpendicularity deviation of the cutting surface. Abstract: The solution of electromagnetic compatibility and resistance of equipment to atmospheric discharges is a very important issue in the development and testing of electrotechnical and electronic equipment. The paper presents a numerical calculation of the parameters of a simplified mathematical model of a trial current and voltage pulse, which is defined by the IEC 61000-4-5 standard. The simplification consists in replacing the current pulse leading time, which is determined by said standard as 1.25 times the time from reaching 10% of the maximum amplitude to reaching 90% of the maximum amplitude, by a time from 0% to 100% of the maximum amplitude. For the solution of the equations for the calculation of the parameters of the simplified model by the numerical Newton - Raphson method, the initial approximation of the solution is determined and the cases when the solution does not exist are determined. Abstract: The paper discusses that the filtration of castings influences the deformed resistance. The article describes the change in toughness in castings using filtration during casting and subsequent changes in mechanical properties after forming these castings. Subsequently, the volumetric compressibility of samples of the same material was monitored. The chosen material is aluminium alloy due to good formability. The mechanical properties after forming on the filtered casting were compared with the casting without filtration. The essence of the tests is to ensure the behaviour of the material in two mutually different environments and to compare the size of the barrel and the susceptibility to cracking on the circumference of the samples. The experiment confirmed the effectiveness of filtering and its effect on the forming force. Abstract: The results of a survey of the reliability of automobile trains in the composition of MERCEDES-BENZ 1844 ACTROS LS trucks and semi-trailers KÖGEL, KRONE, SCHMITZ at different stages of operation are presented. The malfunctions of units and assemblies are revealed, regularities are established, the causes of malfunctions and failures are determined.
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    Technológ 1/2022
    (Žilinská univerzita v Žiline, 2022) Harušinec, Jozef; Suchánek, Andrej; Šťastniak, Pavol; Dižo, Ján; Blatnický, Miroslav; Kravchenko, Oleksandr; Gasper, Peter; Kantoríková, Elena; Moravec, Ján; Solčanský, Sebastián; Brezáni, Miloš; Matejka, Marek; Podprocká, Radka; Čaja, Alexander; Hrnková, Bronislava; Kapjor, Andrej; Vantúch, Martin; Melo, Borislav; Holešová, Natália; Lenhard, Richard; Klačko, Andrej; Zvada, Branislav; Holubčík, Michal; Kuľka, Jozef; Mantič, Martin; Maláková, Silvia; Nicolanská, Miriam; Sivák, Samuel; Harachová, Daniela; Nosek, Radovan; Šavrnoch, Zdenko; Širanec, Lukáš; Bolibruchová, Dana; Galčík, Marek; Brůna, Marek; Pastirčák, Richard; Jakubovičová, Lenka; Kopas, Peter; Novák, Pavol; Sága, Milan; Vaško, Miroslav; Handrik, Marián; Kolesnyk, Olha; Bubeník, Peter; Rakyta, Miroslav; Čapek, Juraj; Sýkorová, Martina; Biňasová, Vladimíra
    Štúdium mechanických vlastností strojných súčiastok s malou hustotou vnútornej výplne vyrobených metódou 3D tlače, 2. časť The article is focused on study of mechanical properties of machine components produced by the 3D printing on FDM (FUSED DEPOSITION MATERIAL) devices by means of a computational model. The article brings details of results of performed tests and a created model for strength analysis using the finite element method. Components of machine produced by means of the 3D printing technology allow to reduce them weight. Currently, this technology is applied not only for production of plastic components, but it is possible to apply it for metal components even other kind of materials. ----------------------------------------------------------------------------------------------------- Vehicle passage over an uneven road Evaluation of mechanical vibration of a vehicle is still up to date. Mechanical vibrations influence dynamic properties of vehicles. They are raised during vehicle driving over an uneven road. Practically, vibrations are deflections of individual components of vehicles. They can lead to slight oscillations or even to significant shocks, which can cause adverse passenger ride comfort, decreased driving safety and extraordinary loading of a road. This article is focused on analysing of vehicle running through an individual road irregularity by means of a mathematical approach as well as on presentation of results of dynamic analysis of a passenger car using a computational model. ----------------------------------------------------------------------------------------------------- Chyby ingotov a možnosti ich eliminácie The paper deals with the production of forging ingots. The basic and necessary data that shed light on the issue are given. The text of the paper presents some selected errors arising in the production of ingots and the possibility of their elimination. The text of the paper is supplemented by pictures and the necessary mathematical relations describing the process. ----------------------------------------------------------------------------------------------------- Návrh brzdového výstroja vagóna s redukovaným počtom spojov: 2. variant This paper deals with the problem of compactization of braking equipment i.e. reduction of pipe joints. The first part contains general look of division of train brakes. The second part contains descriptions of each component of pneumatic part of brake equipment such as, distributor valve, limiting valve etc. The third part deals with descriptions of individual design solutions. The main goal is construction solution in order to reduce pipe joints of brake equipment. This paper represents a continuation of the research presented in the previous number of the journal. ----------------------------------------------------------------------------------------------------- Konštrukcia stĺpového žeriava pre manipuláciu s kalovými čerpadlami a matematický opis závislosti tiaže bremena a ovládacej sily The article brings a technical description of a suspension for manipulation with sludge pumps. It serves for using in the power plant in Jaslovské Bohunice. It is the object for chemical treatment of water belonging to the V2 block. The suspension is used in regular revisions checks of sludge pumps, the Type 80 KDFU150 9.5-A0-03 and for the needed manipulation with them during their operation. This suspension is designed for the maximal load of 120 kg and it was damaged during operation, because it was not designed for all consequences during operation with a sludge pump. It was causing gradual sedimentation of sludge around suction valves of the pump. It has led to the fact, that the pump was stuck to the tank bottom. Then, the lifting of the pump needed even four-times higher force in comparison with the ideal state. Hence, the suspension was not dimensioned for such the great load. Therefore, an optimization is important. ----------------------------------------------------------------------------------------------------- Hodnotenie pórovitosti odliatku vyrábaného vysokotlakovým odlievaním Thus, high-pressure casting of aluminum alloys using a machine with a cold vertical chamber has over time become the most widely used and economical technology. This method has become attractive especially in the production of complex, dimensionally accurate and thin-walled castings. In the experimental part, individual samples of castings, which were cast by the company Rosenberg-Slovakia s.r.o. high-pressure casting, where the castings differed from each other by changing the height of the tube and gradually increasing the maximum speed of the piston. Evaluation of porosity and microporosity was performed on experimental samples. The most advantageous speed among the used speeds in terms of macroporosity and the associated visual control, but with a slight decrease in microporosity in the more critical area, the speed was 3 m∙s-1. ----------------------------------------------------------------------------------------------------- Blechschneiden mit Wärmeanwendung The article deals with to in theoretical part described sheet problematic. In the experimental part deals with search to influence temperature on heating applique. In the contribution to are integrated photos the shears surfaces and is being done valuation results obtained. ----------------------------------------------------------------------------------------------------- Teoretická analýza premeny slnečnej energie na teplo s aplikáciou pre rodinný dom In low-energy and passive buildings, it is essential that energy demand is covered by renewable energy. Buildings require energy in the form of heat and electricity, and the use of solar energy is important to achieve a clean zero energy balance. In projects with ambitious energy targets or limited available areas for local energy production, solar and photovoltaic installations will be a suitable solution in terms of reducing primary energy demand. This article deals with the analysis of the conversion of solar energy into heat in order to reduce the primary energy demand of a building and achieve its net zero energy balance. ----------------------------------------------------------------------------------------------------- Sheet metal bending process at three different temperatures The field of sheet metal bending is an important area of metal forming and therefore considerable attention must be paid to this area, as many similar tasks need to be solved in production practice. This is exactly what the published article, which deals with the area of the sheet metal bending process, should help. The text describes experimental works and their results, which are supplemented by tables and illustrated by graphs of bending forces. the bending process is done in three thermal modes: normal temperature, minus temperature and hot bend. Five samples were bent for each of these groups, which sufficiently illustrate the investigated process. The paper is supplemented by a discussion of the results and in the end an evaluation of the experiments is made. ----------------------------------------------------------------------------------------------------- Reakcia hliníka v prostredí zvýšeného pH Aluminium and most alloys are durable metals. In slightly aggressive atmospheres, passive, electrically non-conductive corrosive layers form on the surface. In heavily polluted environments, corrosion can occur with larger corrosion products, which do not penetrate deeper into the material even after a long time. The subject of the article is aluminium mesh, on which a special layer is formed, resp. a shell that reduces its life. The mesh is used in the paper industry, where it is exposed to acidic, dusty and moderately warm environments. Due to the effect of this environment in production, a brittle layer of shell character was created on the material. ----------------------------------------------------------------------------------------------------- Analýza viacfázových modelov transportu tepla v programe ANSYS Fluent The paper is focused on the analysis of multiphase models of heat transfer in program ANSYS Fluent, because the phenomena of multiphase flow can be observed in many engineering and biological systems. With our rapid progress in engineering technologies, the requirements for the accuracy of the calculations of the physical phenomena that take place in them, have increased. However, it is very difficult to detect two-phase flow by experimental measurements, and therefore numerical simulations are usually performed with experimental measurements, which can contribute to a better physical understanding of the complex phenomena of phase changes. The aim of the article is to introduce the reader to the issue of multiphase flow modelling in the ANSYS Fluent program and the parameter, which is used to correlate CFD simulation, so that it best describes the real experiment. ----------------------------------------------------------------------------------------------------- Fatigue properties of welded high-strength steels This article informs about the experience of the authors in the area of the fatigue life of the welded joints. We are aiming at the welds of the high-strength steel S960 QL. The welds are created by unconventional technologies utilizing the laser and electron beams. The analysis of the residual stresses, assessment of the strength and micro-hardness of the material tested around the welds is also part of this study. The experimental research of the tested material´s fatigue life and welded joints is realized on the samples loaded by cyclic bending and cyclic torsion. The measurement results are processed in the form of the S-N curves and compared with the current regulations issued by the International Institute of Welding in the form of the FAT curves. ----------------------------------------------------------------------------------------------------- Energetické zhodnocovanie komunálneho odpadu na Slovensku Most research is focused on improving the treatment of municipal solid waste (MSW) to obtain usable energy. Pyrolysis technology can not only reduce the volume of MSW, but also produce pyrolysis oil, pyrolysis gas and carbon, which have high calorific values and application properties and are widely used in industrial activities. In this paper, we focus on the research of MSW pyrolysis according to its composition. The components of MSW, including plastics, biomass, and rubber, on pyrolysis products are summarized. In addition, the pyrolysis of raw and extracted MSW in Slovakia is discussed. The article also mentions an existing processing plant for waste recovery using a pyrolysis process. This plant will help us better design our own equipment for the evaluation of MSW. ----------------------------------------------------------------------------------------------------- Prevodové pomery pri ovládaní mechanizmu dávkovača rúrok This article deals with the issue of selecting the gear ratio of the linear actuator as well as the lever transmission of the tube dispenser control mechanism. The genesis of the development of a device for secondary pipe cutting, of which a dispenser is a part, is explained. The forces for actuating the dispenser are calculated and a specific actuator model is selected from the catalogue. ----------------------------------------------------------------------------------------------------- Koncepčný návrh bezdrôtového monitorovacieho systému emisií pre vykurovacie zariadenia na tuhé palivá The article presents a conceptual design of a state-of-the-art emission monitoring system that shall monitor emissions produced by household boilers directly. The aim of the article is to provide low-cost, reliable, and accurate emission data at remote locations, assisting the 2050 Climate-Neutral target set by the European Commission. The sensor devices shall monitor emission parameters such as ozone, carbon dioxide concentration and particle concentrations, specifically concentrations PM2,5 and PM10. Modern "home-made" air quality devices do exist within the market, however, only are applied in indoor climates. The environment within the exhaust of boilers, fireplaces or other heating devices is significantly more hostile, which brings an exciting engineering challenge. The paper first presents a conceptual design of the interface, sensors, and telecommunication unit. Followingly, two CAD models are presented including two attachment systems. The paper later demonstrates a series of future experiments including the setup, the necessary components, and specific aims. In the conclusion of the paper, the data representation is presented along possible countermeasures and strategies that can be done to correct dangerously high levels of measured emissions by the sensors, ultimately aiding to reach the EU Climate target of 2030 and climate neutrality. ----------------------------------------------------------------------------------------------------- Analýza vplyvu tvaru telesa odlievaných čelných ozubených kolies na deformáciu ozubenia Gears are designed in various design types. In accordance with the careful design of the gearing, it is necessary to address the issue of designing a suitable shape of the gear body. In the case of the necessary choice of a lightened gear body, it is necessary to maintain the stiffness of the body itself, but also to remember and take into account the necessary meshing stiffness. The work is focused on large cast dimension gears, made with relief. The shape of the gear body depends on several factors such as the size of the wheel, the material, the method of manufacture or use of the gear. The paper is devoted to the analysis of the influence of the basic parameters of the body of the cast spur gear on the deformation and thus also the meshing stiffness of the gearing. ----------------------------------------------------------------------------------------------------- Konvenčné spôsoby výroby vodíka z fosílnych palív Article deals with commonly used conventional hydrogen production methods like steam reformation, partially oxidation method, auto thermal reformation or, pyrolysis of carbohydrates. This article describes these methods their efficiency and reveals possible improvements to the future based on lowering of impact on our climate by the possibility of carbon capture systems and lowering of energy consumption of the processes, using membranes and using lower temperatures at the process. ----------------------------------------------------------------------------------------------------- Hodnotenie vybraných vlastností hliníkovej zliatiny AlSi5Cu2Mg legovanej zirkóniom The aim of this paper was to analyse the impact of different zirconium content (0.10; 0.15; 0.20 and 0.25 wt. %) on microstructure, mechanical and physical properties of AlSi5Cu2Mg aluminium alloy. The results showed that increasing zirconium content had no effect on the increase in ultimate tensile strength, yield strength, hardness and thermal conductivity values of as-cast samples. After heat treatment, only slight improvement in hardness values compared to as-cast samples were documented in variants with 0.10; 0.15 and 0.20 wt. % Zr. Zirconium rich intermetallic phases were observed in shape of separate thick needles or as a cluster of two crossed thinner needles with a length of 16 to 20 µm. SEM observation showed that these phases crystalized near to the intermetallic phases based on Cu and Fe and at the edges of eutectic silicon regions. ----------------------------------------------------------------------------------------------------- Trendy v znižovaní reoxidačných procesov vo vtokovej sústave počas odlievania Al zliatin Reoxidation processes are one of the main problems influence the final casting quality. The oxid layer can be entrained into melt volume by turbulence, remain in the solidificated casting and negatively affect mechanical properties of the casting. The paper focused on trends in reduction of reoxidation processes during pouring. The naturally pressurized gating system with filter or unconventional elements appears to be a suitable for reduction of reoxidation. ----------------------------------------------------------------------------------------------------- Prístrešok nad terasou - konštrukčný návrh a pevnostná analýza The aim of the paper is to create a structural design and stress analysis of a shelter above the terrace attached to the family house with respect to the specified parameters and to perform its strength analysis. In the theoretical part, the paper deals with the summarizes and characterizes the current designs of terrace shelters, various materials and technological possibilities of the solution and deals with loads. Furthermore, the practical part contains structural design of the pergola model from the CAD system, the analytical model with the results of static and modal analysis, and the eigenvalue buckling analysis. ----------------------------------------------------------------------------------------------------- Perspektívy uplatnenia modularity pri návrhu pohonných systémov v mechanických terapeutických zariadeniach The field of biomedical engineering, called rehabilitation engineering, deals with the design and construction of devices that help the disabled at various stages of the rehabilitation process. Rehabilitation engineering deals with the design and engineering of technical equipment that is helpful to disabled people in the various stages of the rehabilitation process. It is a set of engineering activities associated with the design, implementation and operation of technical means designed to support rehabilitation functions. A drive system is a necessary and necessary part of designing a rehabilitation facility ----------------------------------------------------------------------------------------------------- Heat sources for electron beam welding Nowadays, welding technologies based on the high energy electron beam are able to produce weld joints with very narrow heat affected zone. During welding procedure, softening phenomenon can occur in the heat affected zones and it could lead to the degradation of the mechanical properties of the final joint. The aim of this paper is to investigate the effect of heat source shape on the temperature distribution in an aluminium alloy during electron beam welding. We will vary the diameter of the beam shaped heat source at constant penetration. We investigate the temperature cycles for different heat sources in terms of maximum temperature. ----------------------------------------------------------------------------------------------------- Vplyv metód a technológií riadenia výrobných procesov na marketingovú stratégiu spoločnosti This article focuses on the technologies and methods used to manage the production process and their impact on the implementation of the marketing strategy of the manufacturing company. The marketing strategy aims to combine the market potential, desires, needs and wishes of customers with the goals and intentions of the company. It includes tools, steps and procedures that can bring real customers who will return, as well as the desired profit and the fulfillment of predetermined goals. We must also not forget how the product is produced and what technologies and methods control the production processes, because this is one of the elements of competitive advantage. Marketing is no longer just about the ability to compete and present the company in the market, but also about communication and how the customer and the company respond flexibly to customer requirements. Therefore, the processes in the company must be set up correctly and work without serious errors. ----------------------------------------------------------------------------------------------------- Vplyv tepelného spracovania na morfológiu intermetalických fáz v zliatinách Al-Si-Cu-Mg The present study was undertaken to examine the effect of iron, copper and magnesium on the morphology of intermetallic phases of Al-Si-Cu-Mg-based alloys under different heat treatment conditions. Due to the heat treatment T5, there isn´t significant change in the morphology of the intermetallic phases Mg2Si and Al2Cu, which is beneficial for the resulting mechanical properties of the castings. Further, spheroidization of eutectic silicon is not noted. In general, precipitation hardening of Al-Si based alloys, due to the presence of intermetallic phase Mg2Si and Al2Cu is a result of heat treatment T6. The morphology of Fe-rich phases is not changed by T6. The possitive effect of heat treatment on the morphology of Fe-rich phases is recorded with the simultaneous effect of additive elements such as Mn, Zr, Co. The ability to predict intermetallic phases is important in terms of determining the resulting mechanical properties of Al-Si-Cu-Mg castings. ----------------------------------------------------------------------------------------------------- Vplyv zmeny stratégie na riadenie podnikových procesov This article focuses on the impact of a strategy change on the business process management of a manufacturing company. A strategy is a term for a long-term plan created to achieve one or more goals. The strategy serves both to transfer the requirements of the owners to the management of the organization and to the management of the organization to organize, unify and guide the behaviour and actions of all people in all parts of the organization. The main processes that fulfil the basic strategic direction of the organization and their outputs are intended for external customers. The adopted strategies gradually influenced the set business processes, which needed to be gradually adapted and other action plans applied in the assessment of the business case. The research confirms that the adopted strategies gradually influenced the set business processes, which need to be effectively adapted.