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Optimization of the laser weld of overlap seam for zink layered sheet metal
Plíšek, Roman ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
This diploma thesis deals with the experiment of welding galvanized sheets using fiber laser. The experiment is based on testing of welds lap joints with different gap between the welded parts. Theoretical part of this diploma thesis describes the principles and different types of lasers, laser welding technology, welding defects, galvanizing and inspection of welded joints. In the experimental part of the thesis welding tests and analysis of the results of the experiment have been realised and evaluated.
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Comparison of flame and fusion laser cutting of material DC01
Krejčiřík, Marek ; Horník, Petr (referee) ; Mrňa, Libor (advisor)
This thesis is focused on the technology of laser cutting together with edge roughness for low carbon steel material DC01. The thesis is divided into theoretical and practical part. The theoretical part examines laser itself and contains a physical description of the laser beam with the laser construction, division according to the active environment or the occurrence of laser devices in today’s engineering industry. The last part of the theoretical research is aimed to the surface roughness, its parameters and the measuring technology. The practical part is focused on the comparison of the edge roughness of material DC01 after laser cutting with the usage of flame and fusion. The measured parameters of roughness were further compared with the norm ČSN EN ISO 9013.
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Study cutting quality of flame cutting of limit thicknesses depending on the diameter of the focal spot during laser cutting of material
Maňas, Petr ; Kaván, Martin (referee) ; Mrňa, Libor (advisor)
Experimental work evaluated the dependence of the thickness of the cutting edge, its roughness and assessment of appearance with regard to the defects resulting from the diameter of the focal spot during oxidative cutting Yb:YAG laser. Other variables include the experiment: process parameters such as laser power, cutting speed, oxygen pressure and focus position. Experiment is based on the Taguchi tables. Test samples were cut off from sheet thickness 10, 15 and 20 mm. Representatives of conventional steel were S235JRC+N, S235JR, S235JR+N and steel type RAEX developed for laser and plasma cutting. Samples were evaluated according to the ČSN EN ISO 9013. The evaluation of samples was into classes according to standards of quality. Hardness measurements were performed on the samples thickness 20 mm of convectional steel and steel type RAEX.
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Laser micromachining
Láznička, Pavel ; Daněk, Ladislav (referee) ; Mrňa, Libor (advisor)
This thesis deals with lasers, their general theory and application. Then a theoretical part describes laser micromachining and engraving. Experimental part of thesis deals with several experiments performed by powered fibre laser which is not primarily intended for the field of micromachining. Experiments were mainly evaluated by several types of microscopes where the amount of removed material was appraised. By particular experiments removed material was in accordance with used working parameters of laser and a significant role plays machining material. It emerges from the experiments that for the field of laser micromachining and engraving shorter pulses are more suitable (minimal pulse duration was 1 ms in experiment) and it is connected even with a way of removing material. Applied powered laser can be used for micromachining in specific fields of production.
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Inspection of welded joints of loading ramps
Ertl, Roman ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
This master's thesis is focused on problem of welding of loading ramps and inspection of their welded joints. The aim of this thesis is to inspect the welds of loading ramps with regarding to the appearance of defects. The literature review of the research issues of the MIG welding technology and welding of aluminium and its alloys is described in this thesis. There is also described destructive and non-destructive inspection of welds that can be applied to inspection of loading ramps. Theoretical description is followed by an experimental part of the thesis. Experimental part is focused on the three destructive tests (the tensile, the macroscopic and the hardness test) of samples of loading ramps, which are made of EN AW-6005A T6.
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Optimization of laser welding of carbide cutting plates on a support tube
Franko, Matej ; Daněk, Ladislav (referee) ; Mrňa, Libor (advisor)
My thesis is considering the options of manufacturing of the core drill. One of these options is technology of the laser welding, which was described in details in the theoretical part of this thesis. In applied part of this thesis there were experimentally manufactured two pieces of core drills by using Yb-YAG fibre laser technology. One core drill was used for testing of the welding parameters and in the next step, these parameters were applied in real working conditions and were evaluated in final. Result is written down in the final part of my thesis. The second core drill was welded using the best values measured in the fixture, which was especially designed for this purpose.
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Welding of high strenght steel by laser
Číp, Tomáš ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
This project, elaborated within the engineering studies (code of field of study: N2301), presents experiment of welding of high-strength steel by laser. In this project, the samples of high-strength steel DOMEX 420MC will be welded by laser welding method and the welded joints will then be compared with welds made by MAG method. The theoretical part of this project summarizes the following key words in individual chapters: lasers, technology of welding of steel using laser, welding by MAG method, steel with higher strength, types of defects and check of welded joints. The practical part contains description of and assessment of mechanical tests of welded joints – weld bending test and transverse tension test. Further on, the tests of macrostructure and microstructure of welded joints were conducted and assessed. Final results of whole experiment are reviewed at the end of my diploma thesis.
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Comparison of the of precision manufacturing of holes during laser cutting of materials on various types of CNC cutting centers
Petruška, David ; Dostál, Jan (referee) ; Mrňa, Libor (advisor)
The thesis compares the precision of 90x90 mm laser cutouts with circular and quadrangular holes which are divided into two CNC cutting centers with different axle drive types. On both machines, the samples are cut through both oxidative and fusion cutting. Measurement was carried out using a sliding scale and for a more detailed and accurate analysis on a 3D coordinate measuring machine with a touch system. The results of the measurements showed that the more suitable cutting method for sheet metal cutting CSN 11321 DC01 is melting. Deviations of the nominal dimensions are comparable when cutting on both machines, so the choice of the machine for production speeds, operating and acquisition costs depends on the serial production of these burners.
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Laser welding of steels in automotiv industry
Paleta, Petr ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
In the automotive industry is beginning to replace the resistance spot welding by laser welding. The bachelor thesis was an analysis of laser welding methods, especially the method of remote welding, which is used for the experiment. Furthermore, the use of laser welding was described. We have also suggested the general technological process of welding. The experimental part was carried by metalografic cut of welded sample, which was evaluated by its macrostructure and microstructure.
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