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Analysis of tool steel cracking and a study of its elimination
Tomešek, Viktor ; Polzer, Aleš (referee) ; Píška, Miroslav (advisor)
The aim of this diploma thesis is to describe the causes and mechanisms of degradation processes that affect the surface of tools made of tool steel and to design and verify a practical solution that would lead to higher resistance of tools to these processes. Chapters in the theoretical part deal with fracture behavior of the material and the possibilities of its elimination, the experimental part includes testing of the effect of coating on the durability of hot forming tools.
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HSS end milling cutters with PVD coatings and their use in practice
Vondra, Jiří ; Slaný, Martin (referee) ; Jaroš, Aleš (advisor)
This diploma thesis deals with the durability of PVD coating in front groove milling. In the theoretical part there is the analysis of high-speed steels, a survey of milling and an overview of coating methods. The experimental part is focused on the power ratios during milling with a router cutter and its wear. From the experiment it is possible to conclude that nanocomposite coatings reduce cutting forces, but do not produce the most durable tool under the cutting conditions.
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Enhancement of HSS tools cutting performance with PVD coatings
Medek, Martin ; Sliwková, Petra (referee) ; Píška, Miroslav (advisor)
Diploma work describes speed drill steels and its qualities before and after coating by methods PVD (Physical Vapour Deposition). The theoretic part is concerned with thermic processing of speed drill steels and their qualities with regard to individual alloying elements contained and its mechanical features. Second part of the theoretic part is concerned with particular methods of coating by the help of PVD technologies, kinds of coating with regard to additional elements and their qualities and surface treatments of coated material before and after its coating. The goal of the experimental part was the confrontation of cutting power features of cylindrical four-fluted face mills with straight shank, from speed drill steels non-coated and coated in two basic modes of milling – down-feed method and upfeed method. The results of measurements were interpreted by the help of four basic pictures (source values, power analysis, specific values). The result of all the experiment is that the application of PVD coatings enabled the increasing of cutting speed (with preservation of other cutting requirements) and led to decreasing of cutting force and cutting enforcements and extended durability of cutters.
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Application of PVD coatings for milling
Matuška, Martin ; Sedlák, Josef (referee) ; Píška, Miroslav (advisor)
This dissertation treats of the influence of PVD coats to a change of tool lifetime. The theoretical part of the dissertation describes the adjustment of tools before the process of coating. Following part describes the specific properties of deposited layers of the coating and its measuring. There is also the enumeration and specification of selected ways of depositing PVD coats and brief description of its advantages and disadvantages. Second part of the dissertation is focused on an experiment with measuring of the tool force loading and its change depending to the tool wear. There are compared four short four-edged milling cutters with a coat and as well without it. Those tools were made of high speed steel by the conventional way and also by the powder metallurgy. Milling operation was done by down and up milling technique. The evaluation of the experimental results for powder metallurgy tools confirmed that these tools are advantageous compared to the standard high speed steel tools.
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On the increase of cutting performance of thread cutting taps with PVD coatings
Grygárek, David ; Fiala, Zdeněk (referee) ; Píška, Miroslav (advisor)
This diploma thesis deals with HSS cutting taps performance in combination with very hard and tribological PVD coating application and their contribution to increasing of cutting properties. Then is described the mechanisms and forms of cutting tool wear. The goal of the experimental part of the thesis was determine, compare and subsequently evaluate cutting properties of threading tools using taps with different types of PVD coatings. During realization of the experiment, constant cutting conditions have been ensured and the only variable were the different types of coating layers. The result of the experiment was measurement of cutting torques depending on time and rate of wear of cutting tools. Measured value are statistically processed and drawn conclusion.
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On the analyses of cutiing tools coated with PVD coatings
Malý, Martin ; Osička, Karel (referee) ; Píška, Miroslav (advisor)
In this diploma thesis, literary research about drilling and coating technology focused on PVD coatings was performed. Furthermore, there is an overview of cutting materials. In the experimental part of the work, the attention is dedicated to tests of twist drills from cemented carbide and high-speed steel materials. For these drills, the feed force Ff and the cutting moment Mc were measured when drilling into austenitic stainless steel. At the end of this work, the technical and economic evaluation of the practical part is presented.
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Coating of tools by the PVD HiPIMS technology
Havlíková, Tereza ; Ohnišťová, Petra (referee) ; Píška, Miroslav (advisor)
This bachelor’s thesis is aimed on the study of PVD coatings of tools with a focus on HiPIMS (High Power Impulse Magnetron Sputtering) technology. As part of the research, the PVD coating methods are presented, then the basic physical processes and characteristics of magnetron sputtering are described and finally the HiPIMS technology is analysed. The aim of the experimental part of this study is to evaluate (Al,Ti)N coating deposited by HiPIMS technology on a wire drawing die. For coated and uncoated die, the wear of the die, surface quality and thermal impact on the wire are observed and compared.
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The technology of hot-dip galvanizing
Pometlo, Stanislav ; Osička, Karel (referee) ; Mouralová, Kateřina (advisor)
This thesis deals with the technology of hot-dip galvanizing. At the beginning of this work views into the history of hot-dip galvanizing and analysis of known technologies about applying of melted zinc into the surface of material. It further describes modification for surface before application of zinc´s coating. In the next part of the work are summarized the most common corrosions of hot-dip galvanized material. The work follows up the difficultness of operation for hot-dip galvanizing device. At the end of work describes cooperation with Alka Holding s. r. o.
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Cutting force analysis when tapping
Štokman, Michal ; Sedlák, Josef (referee) ; Píška, Miroslav (advisor)
This master‘s thesis deals with cutting force analysis when tapping. This thesis includes basic methods of manufacture of threads, physical fundamentals of the cutting process, PVD coatings, tool materials, analysis and assessment of the testing nut taps with the application of PVD coatings.
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