|
| |
|
|
Optimization of Machining Parameters Abradable Sprayed used in the Aerospace Industry
Krajkovič, Pavel ; Osička, Karel (referee) ; Kalivoda, Milan (advisor)
This thesis is focused on machining of thermal spray coatings. Particularly on testing of machining parameters and their influence on different types of abradable coatings used in the aerospace industry. The aim of research work is to test the parameters, measure cutting forces by using a dynamometer and their impact on the quality of the machined surface. Determination of the optimal machining parameters for different types of coatings based on results of measurements and the evaluation of surface quality. There are also presented techniques of thermal spray application and methods of coating evaluation. Further it describes a method of measuring cutting forces by using the dynamometer and methods of surface quality evaluation.
|
|
|
Factors affecting the quality of machined surfaces after milling operation
Černý, Libor ; Jaroš, Aleš (referee) ; Fiala, Zdeněk (advisor)
This diploma thesis deals with the final quality of the surface under variable working conditions during milling. The first part deals with the definition of qualitative parameters describing surface properties. This is followed by a brief description of the cutting resistance measurements. The thesis is complemented by experimental verification using front milling and its evaluation. The aim of the experiment is to determine the dependence of the surface quality and the size of cutting resistors under the variable working conditions of the machine that do not make a common part of the manufacturing processes.
|
|
|
Abrasive Water Jet
Kopečný, Libor ; Kalivoda, Milan (referee) ; Osička, Karel (advisor)
This dissertation thesis is focused on explaining the broad issue of the non-conventional machining by an abrasive water jet. Introductory chapters deal with various techniques and methods of water-jet cutting and analyze them. Then the following text provides us with a detailed description of the machine itself so that people can understand the way how this technology works. The third chapter is focused on the quality of the resulting surface and the possibility of affecting it by technological parameters. This part is connected with the practical part of my thesis, in which the resultant surfaces of various materials made by different cutting parameters were compared. Subsequent section outlines the development of this technology. The last chapter contains technical and economic evaluation.
|
|
|
Technology Plasma Beam Machining
Sedlák, Ondřej ; Kalivoda, Milan (referee) ; Osička, Karel (advisor)
This diploma thesis focuses on the unconventional method of metal separation, namely on the cutting technology based on the plasma arc. The introductory part deals with studies which focus on the given issue from a theoretical point of view. The core of the work rests in the practical part which is dedicated to the production of samples using a plasma burning machine called Hypertherm HPR 260. The burned samples are monitored and assessed for the surface quality and dimensional accuracy for every created part. The final part of the work is dedicated to the techno-economic assessment of the burned parts. In the end, the evaluation of the attained results is made.
|
|
|
Suggestion for rationalization of injection mould part production
Kamenická, Eva ; Kalivoda, Milan (referee) ; Sedlák, Josef (advisor)
The diploma thesis deals with suggestion for rationalization of production of an injection mould cavity plate and of a part responsible for cooling of the final plastic product. The main objective is to reduce the production time while meeting the high requirements for dimensional and geometric accuracy and surface integrity of the manufactured parts. The thesis starts with a theoretical analysis of the production of mould parts. This is followed by an analysis of the initial state of production, which consists of the characteristics of the previously mentionned manufactured parts, the available production means and a description of the original technological process. The experimental part of the thesis explains the procedures and justifies the choices made in the creation of new programmes within the CAM software Cimatron. Several possible variations of tools and cutting parameters have been experimentally tested and their final choice is justified in the thesis. The output of the thesis is a new manufacturing process for the production of both components, which has been applied in practice and evaluated on the basis of the results of testing the quality of the components and the plastic product itself. In the conclusion of the thesis can be found an evaluation of the output of the thesis and a time comparison of the previous process with the new suggestion. All experiments and measurements, including the production of the components themselves, were carried out in the toolroom of ITW PRONOVIA, s.r.o. in Veľká Bíteš, which is also the creator of the topic of this thesis.
|
|
|
Porovnání plastových výtisků vyrobených na vybraných modelech 3D tiskáren
JANOVSKÝ, Daniel
In this Bacherol Thesis I am comparing mechanical properties and a surface quality of selected samples, which were printed out using three different 3D printers. Input ma-teriál used for all three printers was plastic. A total of three tests will be performed on the printed samples to compare their properties, namely material tensile test, notch impact test and optical surface quality test. Different 3D printers will be used to print the samples, which are the Creality Ender-3 V2, the PRUSA i3 MK3 and a modified Tevo Tarantula printer with replaced components. The models were processed for 3D printing with PrusaSlicer.
|
|
|
Machining of hardened steels
Veselý, Ondřej ; Osička, Karel (referee) ; Jaroš, Aleš (advisor)
Diploma thesis on Machining hardened steels is focused on the analysis of longitudinal turning of hardened steel 14 109 by using a tool from PKNB in terms of measuring the force load using a dynamometer and then evaluating the surface quality. The theoretical part deals with the issue of turning technology, cutting materials and heat treatment of steel. In the practical part, the influence of cutting conditions on the resulting values was assessed during the experiment. Twelve samples with different combinations of cutting conditions were tested, then was selected a sample that met the criterion of combining minimum cutting forces values and surface quality. The experiment shows that force load values can be achieved twice less by combining cutting conditions with an appropriate combination.
|
|
|
Testing and Analysis of a Broaching Machine
Dvořák, David ; Chladil, Josef (referee) ; Sedlák, Josef (advisor)
This master's thesis deals with the broaching technology. Theoretical part includes the essay about the technology, tools and machines used for broaching. Theoretical part also describes the analysis of the broaching machine testing. Practical part is focused on the collecting, comparing and analysis of the data. These data have been collected during and after the broaching process. The supplier of the new analysed broaching machine is Stenhoj Hydraulik and the older machine has been made by Arpini. The measurements show that the increased number of broached pieces influence the cutting force and the quality of the surface due to wear of the tool which has been also monitored. The measuring dimension through the ball is almost constant. In the conclusion we evaluated the economical aspect of the results.
|
|
|
Development of New Approaches in Descaling in the Continuous Production of Steel using High-Pressure Water Jet
Votavová, Helena ; Hloch,, Sergej (referee) ; Čecho, Ladislav (referee) ; Pohanka, Michal (advisor)
The thesis summarizes general and up-to-date knowledge of descaling during the continuous production of the hot-rolled steel and proposes further streamlining of this process in industrial production. The first chapter of the thesis deals with the origin, structure and physical properties of the scales. The second chapter describes the principles of descaling by using a high pressure flat water jet. The third chapter introduces the principles of the experimental methods and describes the used laboratory equipment. The fourth chapter summarizes the description of the particular experiments and their evaluation, and thus represents the focus of the dissertation. It is divided into six sections which independently solve predefined objectives of the dissertation. The first section focuses on the height and structure development of the scales on 54SiCr6 and HDT580X steels. It has been proven that the height of the formed scales increases with the time and temperature of the oxidation. The layered nature of the scales was verified at the same time. The second section examines the effect of the nozzle stabilizer on the focussing and distribution of the impact pressure of the nozzle. Experiments have shown that increase of 11 % of an average maximum nozzle pressure can be achieved, depending on the type of nozzle and the length of the stabilizer. The third section deals with the analysis of shadowgraphy images of water jet structures of the nozzles. A script was developed for analysis of these shadowgraphy photos by an adaptive thresholding. The findings are correlated using a regression analysis with an average heat transfer coefficient. It has been reported that most of the standard nozzle configurations produced disintegrated stream of little droplets at the height of the rolled surface. The fourth section focuses on the area of water jet overlap, especially the area of the so-called washout, where the impact pressure of one nozzle is reduced by the nozzle stream of the other. The influence of the pressure change and the mutual displacement of the nozzles is investigated. The analysis showed that the change of pressure did not have any effect on the percentage of reduction of the impact pressure in the area of the washout. It has been shown that if the area of the washout is wide the descaling efficiency in this area may be reduced. The fifth section builds on the previous section and focuses directly on the areas of waterjet overlaps. The influence of the change of rotation and pitch of the nozzles is studied. Experiments have shown that small changes in nozzle pitch do not have a significant impact on impact pressure and heat transfer coefficient. The effect of nozzle rotation, on the other hand, was a significant factor for the efficiency and homogeneity of the descaling of the surface. The last section deals with the effect of the rolling speed on the heat transfer coefficient in the descaling process. The regression model has shown that with a higher rolling speed there is a reduction in the average heat transfer coefficient. Conclusion summarizes the results of the dissertation and proposes which findings can be used in the industry to make the descaling process more effective.
|
guest ::
