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The study of the influence of process parameters on the roughness of the cut for flame laser cutting of stainless steel
Kučera, Václav ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
Thesis presents a study of the influence of process parameters on the roughness of the cut surface. The test material is 1.4301, namely austenitic stainless steel. When a parameter is the surface roughness not change too much. In some samples there were defects in the form of cutting burrs. The graphs below show the estimated minimum change one parameter (the lowest point of the curve). As the most important parameter from a technological point of view, cutting speed, constitutes a major cost item compared to the auxiliary gas and power. For samples with a thickness of 2 mm and 3 mm has been achieved good results with decrease in the cutting rate of 30% percent, although when cutting the samples with a default rate was almost identical results. For samples with a thickness of 3 mm the best results were achieved by increasing the speed by 30 %, decrease the rate should be compared with the economy of the process to reduce surface roughness. For changes in the gas pressure was achieved the best values at a pressure increase of 30 %. When you change the performance of the best results are achieved by setting 100–90 % capacity.
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Study of cutting defects in flame cutting of limit thickness of carbon steel by fiber laser
Králík, Petr ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
This thesis deals with research of cutting defects at laser cutting of 15 mm thick carbon steel by Bystronic fiber laser with emphasis on wide cutting gap, which causes enlargement of wide of cutting gap and deterioration of roughness of cutting edge and increase of creation fo heat. The introduction describes the main types of lasers used for cutting sheet of metal and compare their advantages and disadvantages. Also described is a cutting process and its parameters, and also the possible cutting defects. An experiment was conducted on steels S355MC and S235JR and cutting defects were analyzed in relation to the set of cutting parameters. Next part determines the extent of the recommended parameters that should be chosen for specific cutting conditions and is balanced recommendations regarding the choice of material to be cut, and technological adaptations parts. In the last part is measured roughness of a wide cutting gap, the width of the heat affected zone and micro-hardness of the material.
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Techno-economical comparison of the fusing and flame method of laser cutting of steel sheets with a solid-state laser
Vojteková, Lucia ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
The aim of diploma thesis is a comparison of flame and fusion laser cutting of thin metal sheets for ACO Industries k. s. company, where the experimental part was also realized. After consultation with company, the thesis was extended by data samples, which were cut by compressed air for comparison with other two gases. The optimization design of cutting parameters was created by Taguchi method. Afterwards the surface roughness of samples was measured. Based on Ra and Rz5 parameters, the samples were classified to classes based on their accuracy according to ISO 9013 standard. According to results the fusion method of laser cutting is more suitable method, especially for its good quality of cutting edge, which is not affected by the oxidic layer. Fusion method uses cutting speed two times higher than the flame method, which leads to decrease of time and financial consumption of the process despite of its higher hourly rate. In case of laser cutting of material by compressed air the quality of cut is insufficient in comparison with fusion or flame cutting method.
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Optimization of laser fusion cutting of coated aluminum sheets
Pokorák, Milan ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
The thesis primarily deals with the optimization of laser cutting center for coated aluminium sheet cutting and with the subsequent comparison of measured results and a sample made using waterjet cutting. The thesis is divided in two parts, the theoretical part followed by the practical one. The theoretical section is concerned with the unconventional technologies used, with their general analysis, design, history and utilization for industrial appliances. Main parts of this thesis deals with classification of particular cutting principles and their specific description. The theoretical part contains also classificaton of aluminium alloy, description of surface texture measurement and explanation of basics terms used for roughness measurement. The practical section is concerned with the particular task solution and with all knowledge used for optimization and evaluation of laser cutting. This part contains the measurement results, the measured material, the machines and devices used and also the technical and economical evaluation of this thesis content. The overall evaluation of the laser cutting optimization of specific component is mentioned in the experiment outcome evaluation article.
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Plasma cutting by TransCut 300.
Bergauer, Radek ; Hála, Michal (referee) ; Kubíček, Jaroslav (advisor)
The thermal parting by plasma is progressive technology of material cutting. There is a new method based on the plasma stabilization by the steam, beyond common systems with gas stabilization. The potentialities of cutting by steam stabilized plasma are tested and the results are compared with regular gas plasma in this diploma thesis.
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Measurement of roughness of the laser cutting edge
Vaculka, Jakub ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
This bachelor thesis elaborated as a part of branch 2307 engineering studies describes metal laser cutting and its industrial use. The thesis consists of theoretical part and experimental part. The theoretical part describes physical and constructive principle of industrial lasers, its individual types, advantages and use. The experimental part goes into results of common quality steel oxidizing cutting. The CO2 laser from TRUMPF company was used in this experiment. Cut defect appearance and final roughness of cutting edge were the subject of evaluation. The conclusion summarizes effect of material chemical composition and cutting proces parameters on cutting results.
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Technical and economic solving of barking knives
Novotný, Petr ; Hála, Michal (referee) ; Kubíček, Jaroslav (advisor)
The target of the study is theoretical explaining the condition of creation of the soldered point with regard to basic and additional mat. Below, the detailed analysis of the existing technical problem and consecutive design of the solution method.Content of the study is also technological process of production of the barking knife and choice of the efficient producer.
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Measurement of roughness of the laser cutting edge by Yb-YAG laser
Dočekal, Miroslav ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
The project carried out in the bachelor's degree program B - STG (“Mechanical Engineering Technology”, 2303R002), evaluates the roughness of the cutting edges of steel plates cut by laser according to the ČSN EN ISO 9013 standard. The test samples were cut by Yb - YAG laser. In total, 11 samples were measured. The samples represent three kinds of material and were cut by two ways of laser cutting; the fusion method and the oxidation method. The samples of stainless steel X10CrNi18-8 were cut by the fusion method and the remaining samples of the DC 01 steel and S235 JRG steel were cut by the oxidation method. The samples were evaluated according to the ČSN EN ISO 9013 standard. The standard evaluates the quality of cut in thermal cutting and classifies individual cuts into accuracy classes. The samples of stainless steel fall into the first and second classes of accuracy. The samples of structural steel all fall into the second class of accuracy. This classification is the outcome of the practical part of the project. The theoretical part deals with the basic principle of laser, its parts, the industrial use of lasers and the lasers most commonly used in industry. It focuses particularly on laser cutting and the parameters which affect the quality of the cut in laser cutting. The measuring of roughness and the ČSN EN ISO 9013 standard are also described.
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Laser cutting with air pressure assistance
Kramoliš, Lukáš ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
This project, elaborated within the engineering studies (code of field of study: N2301), deal with air supported laser cutting and its practical usage in industry. The project is divided into theoretical and experimental sections, consisting of detailed description of several successive steps of the experiment. The theoretical section describes the principle and function of laser, individual types of lasers and their classification, laser beam properties, laser cutting, etc. The practical part is focused on finding of a set of optimal cutting parameters, assessment of results of air supported laser cutting in terms of quality and accuracy of cutting surface. This part is followed by comparison of cutting surfaces with a conventional technology of laser cutting that uses oxygen and nitrogen. Final part of the project evaluates applicability of this unconventional technology from the economic point of view.
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Arc welding of stainless steels for demanding working conditions
Matějíček, Josef ; Hála, Michal (referee) ; Kubíček, Jaroslav (advisor)
Bachelor thesis introduced deals with Arc welding of stainless steel. With welding technology, used by company DIAMO, the connected pipes, flanges and plates are for guiding the Sodium Sulphate solution, which is obtained as by-product in production of Uranium. Corrosive attack and weld cracking occurs in the short period of time due to the chemical reaction. Based on information about materials, used additional materials and welding technology used I have evaluated materials with susceptibility to the corrosion and the formation of hot cracks. Using tests and calculations I have examined the susceptibility of austenitic stainless steel to intergranular corrosion. Austenitic-ferritic stainless steel was also used as a theoretical solution for larger spectrum of materials. After calculations and evaluations of the trial tests I have conducted discussion and recommendations for use in practice.
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