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Laser brazing in the car industry
Podstavek, Michal ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
The project elaborated in frame of engineering studies of the subject M-STG Mechanical Engineering describes elementary methods of joining in the automotive industry. Moreover, it inquires into optimization of laser brazing on the back cover ŠKODA Superb. During the optimization of the process six samples were designed, and the adjustment of the brazing parameters were performed. Consequently, the samples were evaluated by tensile and metallographic tests. Finally, EDS analysis was performed and visual assessment as well.
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Evaluation of the fillet weld geometry on process parameters for laser welding of stainless steel
Polášek, Marek ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
The present thesis deals with welding of samples to examine the resulting geometry of the weld in dependence on process parameters of the laser. Welding was carried out without additional material using a fibre laser. The material used was stainless steel ČSN EN 17 241. The values of regression coefficients of the resulting graphs show that the changes in the weld geometry - width and depth - vary quite linearly depending on the welding performance. Especially the weld depth is a common requirement in technical practice; the measured results of the experiment can be used to set the process parameters to achieve the desired depth of weld. Some welds exhibit weld defects such as porosity caused by formation of the keyhole due to a large dynamics of the process. The technical-economic evaluation offers a price estimate for one meter of weld for each welding speed used.
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System for measuring of thermal efficiency of solar absorbers
Řiháček, Jan ; Podaný, Kamil (referee) ; Mrňa, Libor (advisor)
The thesis deals with the measurement system for determining the thermal efficiency of the newly developed types of solar absorbers. Measuring equipment allows simultaneous indoor or outdoor thermal efficiency detection of up to four samples absorbers. Emphasis is placed on the flow and heat transfer medium temperature changes. For this purpose is used Biotech FCH-m-POM-LC and LM35DZ sensors. Sensor signal is transferred to a PC using the measuring module NI USB-6221. Here it is further processed by proposed evaluation program. The software is implemented in LabVIEW integrated development environment. In a final part are performed a verification measurements to assess system performance and evaluate the thermal efficiency of various types of solar absorbers. This path is also demonstrated high efficiency applications absorbent layer coating color RABSORB 5.
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Compare weld from CO2 laser and fiber laser
Leidorf, Michal ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
The project compares the technology of welding of CO2 laser and fiber laser in terms of engineering study, the welds will be made by same welding conditions on two materials (S235JRG2 a X5CrNi 18-10), by using different protective gases (Helium and Argon). In the terms of literal background research both the technologies and questions of laser welding are described. The geometry of welds is carried out in the experimental part. The final results of the experiment are concluded at the end of the diploma thesis.
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