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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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The production of domestic grill
Blahák, Radek ; Hála, Michal (referee) ; Kubíček, Jaroslav (advisor)
The work deals with the production of domestic grill from discarded storage pressure vessel domestic water of non-alloy steel grade 11 373. The work is divided into theoretical and experimental. The theoretical part is devoted to the study of the manual electrode welding, design appropriate welding parameters and selection of welding electrodes. Further work is focused on graphic design of the grill, under which it will produce grill. The practical part is devoted to verification of appropriate welding parameters for the selected electrode to the control samples, evaluation, and then use the most appropriate type of electrode and the welding parameters for the design of the grill.
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New aspects of MIG/MAG welding
Minich, Marek ; Hála, Michal (referee) ; Kubíček, Jaroslav (advisor)
The thesis discusses the welding method MIG/MAG and the methods based on it. These methods are CMT and CMT Advanced which are currently still being improved. In the work are described their principles, benefits, uses and devices that allow welding by those methods. The thesis deals with the issue of a joint of steel and aluminum which is no longer an obstacle in welding due to CMT. This is a huge benefit especially for the automotive and aerospace industries, for which the solid and fast connection between steel and aluminum is a very desired matter. Further, there are welds of thin sheets described and discussed and also a list of wide range of practical uses for these welding methods.
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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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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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Weldig of the different type of steel by the Yb-YAG laser
Chlád, Luboš ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
The master's thesis presents an experiment of welding of high strength steel Docol 1200 M and of steel DC01 by the fiber Yb-YAG laser. The experiment is based on testing welds which were made during the experiments. The lasers, laser technologies of welding, steels of higher strength, tailored blanks technology and testing of welds are described in the theoretical part. The practical part contains description and evaluation of tests of welds – transverse tension test, Vickers hardness test, Erichsen cupping test and macrostructure and microstructure test. The final evaluation results of the experiment are presented in the conclusion of the master's thesis.
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Locating welds defects on cranes.
Zíka, Luboš ; Hála, Michal (referee) ; Kubíček, Jaroslav (advisor)
The diploma thesis deals with the problematics of weld defects of cranes localisation and check. The aim is to analyse non-destructive methods, monitor the occurence of defects and their form and also to suggest the procedure of correction. The work is divided into a theoretical and practical part. In the theoretical part, there is an analysis of individual methods of non-destructive testing that are used for weld check on a particular girder. There is also an analysis of welding technologies used when making a crane girder. The practical part deals with evaluation of weld defects using two methods of non-destructive testing. Furthermore, statistics of defects is realised. In conclusion, the statistics outcome is resumed and evaluated.
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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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Comparison of oxy and plasma cutting
Solař, Luboš ; Hála, Michal (referee) ; Daněk, Ladislav (advisor)
This diploma thesis is focused on comparison of plasma and oxygen - acetylene cutting. A literature review of this issue is included in the work. For technological - economic evaluation, there were proposed a sample part to assess how optimal the cutting process is. Observed resulst and there comparison are stated in conclusion.
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