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Design modification and CFD simulation of the filling valve
Klíma, Štěpán ; Kohút, Jiří (referee) ; Klas, Roman (advisor)
This thesis deals with the design of a filling valve guide using a metal 3D printing method for application in a hydraulic press. The production of a filling valve guide using traditional forms of manufacturing in terms of labour, production, technology and time-challenging processes and the metal 3D printing method can help to overcome some of these challenges. The introduction of this paper is concerned with explaining the function of filling valves in the hydraulic press mechanism and a brief introduction to valve guide manufacturing technologies, including metal 3D printing technology. This is followed by an explanation of the new design in terms of the technology used. A strength analysis using FEA is then developed to determine the functionality of the valve guide and to optimise its shape. In this section, an iterative procedure was used to reduce the reduced stress in the ribs to 68 % of the reduced stress of the original design by changing the valve guide geometry. At the same time, a theoretical introduction to FEM is written, including an explanation of the non-linearities in FEM. This is followed by a comparison of the hydraulic losses due to oil flow through the original valve and the valve with the modified valve guide. Similar to the FEM chapter, a theoretical section is also written introducing CFD, mesh generation for CFD and turbulence models.
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Use of torch oscillation for butt and fillet weld welding of high-strength steels using the MAG method
Umlauf, Petr ; Slováček, Marek (referee) ; Kubíček, Jaroslav (advisor)
The first part of the thesis deals with the research on high-strength steels, their structural effects, weldability, metal transfer methods and common weld defects occurring in these steels. In the practical part, an experiment is designed to investigate the effect of weaving on butt and fillet welds, two specimens are prepared for each type of weld, one with weaving and the other control without weaving. The macrostructure, microstructure, hardness was evaluated on the specimens and tensile test was performed on the butt joint and a fracture test was performed on the fillet joint.
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Design of wire feeder for TIG process
Kozumplík, Filip ; Slováček, Marek (referee) ; Kubíček, Jaroslav (advisor)
This thesis describes the design of a wire feeder for TIG welding, its drive and control electronics, capable of reacting to changes in welding parameters. First, different types of drives were compared and their suitability for the wire feeder was evaluated with regard to their regulation, precision, speed and torque. A stepper motor with a planetary gearbox was selected. Then, a shaft adaptor has been designed, coupling the gearbox to the wire feed. Based on strength calculations were obtained the requirements for mechanical properties of material for its production. An adaptor body from an aluminum alloy has been created, housing the shaft adaptor and to which the gearbox and wire feed are mounted. Also, the control Electronics have been designed. The control system is split into several boards, each fulfilling a specific purpose. A circuit has been developed, capable of a safe measurement of arc voltage and able to withstand the high frequency ignition pulse. In addition, a circuit for protection of the drive against said pulses, circuit for detecting contact between the filler wire and the workpiece, main control board with a microcontroller and a control panel have also been designed.
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Weldability of hardenable aluminum alloys
Filip, Josef ; Slováček, Marek (referee) ; Kubíček, Jaroslav (advisor)
The thesis deals with the influence of MIG pulsed metal transfer welding on the mechanical properties of the aluminium curable alloy and on the presence of defects in the welded joint. The aluminium alloy EN AW 6082 T6 was chosen for the experiment, i.e. in the state after the artificial ageing. The experimental part first describes the selected base and filler material, the used welding equipment, the choice of welding parameters and then the preparation process of the test samples is described. There were made 6 sets of samples, each of them was welded with a different combination of welding parameters and pulsed welding mode. Subsequently, the work deals with several material destructive tests that were part of the experiment. Tensile tests, hardness measurements and microstructure tests were performed. The results of the tensile tests showed that in all cases the tensile strength was decreased by more than 30% compared to the base material and similar values were achieved. Thus, the theoretical assumption that soluble precipitates occur during the welding of hardened Al alloys, causing a decrease in the mechanical properties in the HAZ, was confirmed. It is evident in the results of hardness measurements, which for all samples reached the lowest values in the HAZ at the same place where fractures occurred in the tensile tests. The macroscopic examinations then showed the presence of micropores in all samples except the set num. 4, which did not develop porosity. In several cases, the presence of unbroken or oxide inclusions was also detected. The results are evaluated at the end of the thesis.
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Welding inverter
Lizúch, Ján ; Vorel, Pavel (referee) ; Martiš, Jan (advisor)
The aim of a masters thesis is to design components, circuits and to build welding power source. Description and technological process of welding, arc characteristic and welding methods requirements are included in a first part of the thesis. Switching mode power supply topologies are characterized in a next part of the thesis. At the end of a theoretical part, the parameters of welding power source are determined. Its design is described in the next parts of the thesis where calculations and design process of electrical part is described. There are also schematics of circuits shown. In each power part is power dissipation calculated, what is needed to design cooling. Practical build and tests of welding power source are described in the last part of thesis. Measured waveforms and thermal camera images during load test are included in the last part as well
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Porosity during welding aluminous alloys
Hájková, Alena ; Daněk, Ladislav (referee) ; Sigmund, Marian (advisor)
This thesis deals with the problem of occurrence of porosity in aluminous alloys and the methods of their repair in the company IFE. Theoretical part is aimed on the current state of porosity and the ways in which the be pores can be repaired. Used technologies of repairs are TIG welding and cementing. The practical part consists of experiment in which is used a method of cementing on specific part.
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The design of table belt sander
Šimčík, Jaroslav ; Pavlík, Jan (referee) ; Bradáč, František (advisor)
Jaroslav Simcik The design of table belt sander BP, Institute of production machines, systems and robotíce, 2008, p. 41, fig.19, appendices 15 This bachelor´s thesis belongs in the domain of wood-working engineering with a direction on a construction of a belt sander. The surface speed of a abrasive belt has to be 11 metre per second.
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Exposure to Nanoparticles in Work Environment
Köbölová, Klaudia ; Mikuška, Pavel (referee) ; Adamec, Vladimír (advisor)
Outside to the wide range of potential benefits, the use of nanomaterials can endanger human health and the environment. This diploma thesis presents the results of pilot measurements, where the exposure of nanoparticles was monitored. Based on a literature research a suitable method for measurement was the three-stage OECD model. Based on this model, measurements were performed in three welding workplaces, where nanoparticles are produced incidentally. The measurement consisted of collecting information and measuring the concentration of nanoparticles in the workplace, where data collection was focused only on inhalation exposure. During welding, 0.3 m size particles are produced and their concentration is strongly influenced by the welding material, type of welding and suction. The particles are amorphous in terms of morphology and contain manganese, iron and silicon, which can cause neurodegenerative diseases. Furthermore, the results indicate the importance of monitoring oral exposure.
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Structual welding of aluminium alloy
Blahák, Petr ; Hála, Michal (referee) ; Kubíček, Jaroslav (advisor)
The project elaborated in frame of engineering studies branch 2303R002 presents a project that contains welding a structure made of aluminium alloy. There were two usable methods selected, based on literal study of welding aluminium alloys, TIG welding and friction welding, and these were compared with alternative methods of joining, hard soldering and bonding. A work procedure was made for TIG method, soldering and bonding and four experimental joins were made thereafter. Project compares these methods mainly in economical way, also in way of technological difficulties and in way of observance the strength of base materials. Project also deals with problems with lowering strength of base material in heat affected area, burn out of thin material, tendency of aluminium to fill with hydrogen, quick oxidation and consequent hard surface layer emerging on the aluminium.
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