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Evaluation of Surface Quality When Using AWJ And WJM Cutting Methods
Pecháček, Martin ; Dvořák, Jaromír (referee) ; Slaný, Martin (advisor)
This study deals with technology of abrasive water jet material cutting and influence of cutting head feed rate on surface topography of cut walls with regards to roughness. Eight parameters were chosen based on the CSN EN ISO 4288 standard representing quality of surface after AWJ cutting. When AWJ cutting the chosen material – commercially pure ASTM B265 grade 2 titanium – feed rate was being changed and in order to obtain information about each parameter´s distribution in various depths of the cut, surface composition was evaluated. It was found out that feed rate has significant influence on surface and that the profile elements´ width grows when increasing the feed rate and cut depth. Furthermore, two selected feed rate results were compared to laser beam technology and conclusion for the selected material was made that AWJ cutting is more preferable due to final roughness and no heat affect on the material.
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Unstability cut of laser beam at dividing limiting gauge thickness
Kadlec, Zdeněk ; Kalivoda, Milan (referee) ; Osička, Karel (advisor)
This thesis deals with the possibilities of cutting strong steel metal sheets by means of laser and problems rising from the incision, their technological investigation. The basic philosophy consists on the research of the interaction between laser bunch and material, depending on the position of focal poin and sequential results in spec. heat. It determines the main parametres of the incision (from the total quantities and matematical description) which have the biggest effect on the occurence of wide cut and perhaps even on the quality of products and consequential optimalization of these quantities.
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Influence of atmospheric turbulences on laser beam intensity profile
Císař, David ; Wilfert, Otakar (referee) ; Hudcová, Lucie (advisor)
Free space optical communications provide a reliable alternative to microwave and cable system applications. This technology is utilized for an optical links between ground stations, and moreover for links between High Altitude Platforms (HAPs). The main goal of the project is to gather knowledge about degradation of an optical beam in the atmosphere. The optical beam is being exposed to many factors such as intensity fluctuation based on turbulence, attenuation due to absorption and scattering. Furthermore, an emergence and influence of the atmospheric turbulences on the intensity profile of the laser beam are discussed. At the end, the methods of atmospheric turbulence measurement are given.
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Automated measurement of polarisation properties of an optical beam
Březina, Vojtěch ; Vlček, Čestmír (referee) ; Poliak, Juraj (advisor)
Diploma thesis deals with polarization properties of an optical beam and the determination of its polarization state by means of the proposed automatic measurement method. Furthermore the influence of an environment on the polarization state of the optical wave is studied. At the beginning of this thesis the fundamental terms with respect to the wave polarization including the description of the polarization devices are presented. In conclusion a method for an automated experimental workplace for the measurement of the polarization properties using Poincare sphere and Stokes parameters is designed and verified.
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Computer modeling of laser beam
Mittner, Ondřej ; Wilfert, Otakar (referee) ; Raida, Zbyněk (advisor)
This bachelor’s thesis theoretically describes Gaussian beam, its characteristics and its passing through optical elements. The main attention is focused on creating of computer models of Gaussian beam in COMSOL Multiphysics application, detailed description of these models, presentation of achieved results and comparing these results with theoretic presumptions.
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Measurement of laser beams parameters
Vrábel, Miroslav ; Kvíčala,, Radek (referee) ; Hudcová, Lucie (advisor)
his paper discusses the characteristics of laser radiation. Introduces the theory and in quite a description of the laser beam. To this end, experiments were compiled to measure the geometric and performance parameters, polarization and coherence. Emphasis is placed on the interdependence of the various parameters of laser radiation
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Digitalization of the optical intensity distribution scanning
Škrob, Robin ; Hudcová, Lucie (referee) ; Křivák, Petr (advisor)
This Master’s thesis solves a design and construction of device for gathering and transfer of data into computer. The device should replace graph plotter, by which is measured the optical intensity of a laser beam. From this characteristic it is possible to determine other parameters of the laser beam, such as halfwidth of the beam, angle of divergence and Rayleigh length. The described device - “data gatherer” - measures two voltage values – voltage detected on photodiode and voltage detected on distance moved by photodiode. Measured values of voltage are processed and sent through a serial line into the computer. A pre-amplifier is connected to the control part for both channels of measured values with possibility of amplification. Computer application, which performs graphic interpretation of the measured values, serves as user control peripheral. The product of this project is compact device operating under OS Windows with graphic output.
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Advanced laser diagnostic systems to measure flow field
Loutocký, Petr ; Lízal, František (referee) ; Jedelský, Jan (advisor)
The aim of this work is to give readers a comprehensive view of the present laser methods for measuring the velocity of fluid flow. The methods are classified and compared according to various criteria. Individual techniques are briefly outlined their principles of measurement, options and range of applications. Furthermore, this work discusses the advantages and disadvantages, appropriate areas of application and the basic parameters. At the end we can find a sample analysis of data measured by one method.
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