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Design of the PKD cutting edge cutter
Křehlík, Luboš ; Trčka, Tomáš (referee) ; Polzer, Aleš (advisor)
The thesis deals with the design, construction, production and testing of cutters with polycrystalline diamond cutting edges. Polycrystalline diamond is a suitable cutting material for machining very abrasive materials such as aluminum alloys or composite materials. The design of the tool is focused on the application of the chip breaker on the front of the tool. The aim of the solution is to reduce the cutting force in the machining of the aluminum alloy used in the aerospace industry. The first part of the thesis deals with problems related to milling technology. The practical part describes the design and construction of prototype cutting tools. Three tools were designed for experimental measurement. The technology of cutting tools made from super hardened cutting materials with laser technology is presented. The experimental part of the thesis is a measurement of the cutting force according to cutting parameters and machined material.
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Production technology for valve housing
Zimmer, Jakub ; Trčka, Tomáš (referee) ; Zemčík, Oskar (advisor)
This bachelor thesis is a proposal how to manufacture a valve housing. The work deals with the analysis of component, design technology, including the choice of machines, tools and gauges. The proposed technology is supported by the NC program. Variant technology is also ready for the part. All proposed technologies are evaluated technically and economically.
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Analysis of the force loading of the end mills with PCD considering their sharpening
Trčka, Tomáš ; Kalivoda, Milan (referee) ; Polzer, Aleš (advisor)
Measurement of the force loading is a significant type of measurement in mechanical engineering applied to analyse important aspects in the machining process. In addition to the determination of specific material constants, it is possible to analyse, for example, various machining strategies, geometries of tools or the degree of wear of the cutting edges of cutting tools. This master’s thesis deals especially with the last two mentioned aspects which are subjects of an experiment on end mills with PCD inserts sharpened by a different technology. In the introductory part the cutting forces are theoretically analysed along with their measurement possibilities and the technology of the production of the mills including their sharpening – WEDM and EDM-G. One chapter is concerned with the milling of plastic materials, as PVC was the material used for the workpiece during the experiment. The first experimental part is devoted to the analysis of sharpened tools followed by the measurement of forces using the piezoelectric dynamometer and the subsequent analysis of the influence of the different tool geometry. The last conducted experiment monitors how the overall cutting forces of individual end mills sharpened by different technology changed over specific milling time slots.
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Application of Electromagnetic and Acoustic Emission for the Diagnostics of Advanced Composite Materials
Trčka, Tomáš ; Chobola, Zdeněk (referee) ; Lokajíček,, Tomáš (referee) ; Koktavý, Pavel (advisor)
The subject of this dissertation is a theoretical and experimental study of electromagnetic and acoustic emission generated in the course of crack formation in solid dielectric materials. Theoretical part of this work is focused on the electromagnetic emission method, because it is related to a number of unsolved problems in the field of generated emission signals measurement, as well as in the field of the correct interpretation of obtained experimental data. Consequently, issues of emission signals detection by capacitance sensors and the transformation of crack primary parameters on the measured variables within the proposed transfer system have been dealt with. The results in this area were an extension of application range of the electromagnetic emission method on composite materials (especially on fiber reinforced polymer composites), identification and evaluation of the most significant emission sources in investigated composites and developing a methodology for evaluating of the crack primary parameters based on the measured emission signals waveforms in time and frequency domain. The experimental part of this dissertation was focused on a complex methodology for emission signals (including data from additional sensors) continual recording, processing and evaluation and for monitoring the response of stressed material to an applied mechanical load in real-time. Partial results from different research areas were also implemented into this methodology. This included the detection of emission signals, design and implementation of the appropriate measuring apparatus, analysis of measured signals in the time and frequency domain and advanced methods for processing and evaluation of measured data.
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Design of thermal system for accurate temperature stabilization using Peltier thermoelectric modules
Motl, Jakub ; Trčka, Tomáš (referee) ; Macků, Robert (advisor)
This master’s thesis describes design procedure of a heat-regulating system to stabilize its temperature using a Peltier module. The implementation uses eight-bit microcontroller ATmega16 made by company ATMEL for the local and remote control system. The temperature sensors communicate with the microcontroller by serial SPI interface. To display user data, it has a DEM16217SYH type character LCD display with HD44780 control circuit. To collect data from the cooling areas of Peltier module, accurate ADT7320 temperature sensors are used, made by company Analog Devices. The Control of the Peltier module happens in two points of the electrode system and a bistable hysteresis software regulator is used. The first part summarizes the theory, which concerns with the design. Next part concerned with issues of the Peltier module, overview of temperature sensors, description of the microcontroller, the display unit and the used regulator. Last part describes the hardware and software implementation.
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Turbocodes and their application in telecommunication systems
Trčka, Tomáš ; Křivánek, Vítězslav (referee) ; Němec, Karel (advisor)
This Diploma thesis deals with Turbo code problems. The Turbo codes belong to the group of error correction codes, sometimes referred to as forward error correcting (FEC) codes or channel codes. This thesis can be thematically divided into two basic parts. The first part describes turbo code encoder and decoder block diagram with the illustration of two most frequently used iterative decoding algorithms (SOVA and MAP). The end of this part contains best known turbo codes, which are used in present communication systems. The second part pursues simulation results for the turbo codes using Binary Phase Shift Keying (BPSK) over Additive White Gaussian Noise (AWGN) channels. These simulations were created in the MATLAB/SIMULINK computer program. It will be shown here, that there exist many different parameters, greatly affecting turbo codes performance. Some of these parameters are: number of decoding iterations used, the input data frame length, generating polynoms and RSC encoders constraint lengths, properly designed interleaving block, decoding algorithm used, etc.
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Hardness measurement of metal materials
Trčka, Tomáš ; Kandus, Bohumil (referee) ; Podaný, Kamil (advisor)
The hardness is the mechanical property of each metal material that affects his behaviour. There are many methods of measurement. Each method has its advantages, shortcomings and possibilities of use. The best known tests are according to Brinell, Vickers and Rockwell. The newer methods with portable hardness tester are UCI, TIV and the dynamic method by Leeb. The tests are carried out by mechanical pressure load using the impact body (indenter) of the harder material than the test material. The experimental measurement was executed on the three types of cutting inserts with different nominal hardness made from cemented carbides using the Vickers method with the load of 10 kp and 30 kp. The highest value of hardness was measured on the cutting insert SMG02 - 1988 HV10.
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