National Repository of Grey Literature 44 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
An investigation of friction and lubrication of coated hip joint replacement
Balcárek, Ondřej ; Horák, Zdeněk (referee) ; Nečas, David (advisor)
The thesis focused on studying the effects of a new hydrogel coating and material combinations on the coefficient of friction and formation of lubricating film in the conformal contact of hip joint replacement. Experiments were conducted using a ball-on-cup configuration with a hip pendulum simulator. The formation of the lubricating film was observed using fluorescence microscopy. The results showed that the application of the coating did not have a clear impact on the coefficient of friction. However, for pairs with a coated cup, there was a reduction in CoF by approximately 20%. Generally, lower friction was observed when using a ceramic joint head. Surprisingly, even more interesting results were obtained in the lubrication analysis, where the use of metal heads led to a reduction in the thickness of the lubricating layer. Ceramic pairs exhibited very stable behavior. In addition to friction and lubrication, the topography of the implants was further evaluated, and their wettability was analysed. Although the polymer coating was expected to be highly hydrophilic, the surface properties were only slightly influenced, which partly explains why there was no significant improvement in the tribological behavior of the replacement. As the coating applied is already patented and its effectiveness in reducing wear has been clearly demonstrated, it is appropriate to investigate this issue further, with more attention being paid to long-term experiments. Based on the obtained data, it appears that the short-term benefits of the coating are practically negligible. However, it is important to highlight that, except for minor exceptions, the application of the coating did not lead to a deterioration of properties, which is a significant outcome of this work.
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.
Friction analysis of hip joint replacements with coated surface
Nosek, Matěj ; Streďanská, Alexandra (referee) ; Nečas, David (advisor)
This bachelor thesis focuses on the effect that results from applying a coating to hip joint replacement based on the friction coefficient. The aim of this thesis was to conclude a comparison between individual combinations with and without coating in three types of fluids. Experimental measurements were conducted in configuration ball-on-head in a pendulum hip joint simulator. For these measurements, DEWEsoft, MATLAB, and MS Excel were used. During the measurements, four balls, two cups, and three fluids were used. The coating is a polymer-based solution made out of PEGMA-360 a PEGDMA-550. With the usage of the coating, gathered results point out that the coefficient of friction declines by a maximum of 5,4 % and increases by a maximum of 16,1 % compared to those without any coating. Results presented by this thesis may be in the service of further research of coatings and their application on hip joint replacement, which might increase the potency of those implants.
COSIM - Coating Simulation
Jílek, Jan ; Kofroň, Jan (advisor) ; Malohlava, Michal (referee)
In the given coating chamber is a system of rotating holders, which holds rotating tools. The chamber also contains electrodes (of various materials), from which the material evaporates and is coating the tools. The goal of this thesis is to simulate the process of coating and visualize the resulting layer in given places of coated tools depending on their placement, number, rotation speed and other optional settings.
Modern surface coating of cutting tools for machining
Tříletý, Vlastimil ; Ohnišťová, Petra (referee) ; Píška, Miroslav (advisor)
This bachelor thesis consists of two main parts. The theoretical part generally describes methods for coating cutting tools, wear mechanisms of cutting tools and experimental evaluation of coating properties and evaluation of tool life. The practical part is focused on the evaluation of tool life based on the observation of the development of wear using a scanning electron microscope.
Komplexní technologie výroby součásti
Forbelský, Michael
The aim of the work is to create practical and describe the production technology of a particular komponent. It is supported by theoretical knowledge concerning this tech-nology and gained by work experience. This bachelor theise also discuss the issue of coated components and overall economic assessment of machine components in terms of optimization of production costs.
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.
Thin metal coating of polymer materials
Zatloukal, Filip ; Furmann, Denis (referee) ; Nečas, David (advisor)
The study of compliant contacts from a tribological standpoint is very complicated due to low reflectivity and electrical conductivity of materials such as polymers or rubber. These properties significantly limit the possibilities of using conventional methods which are being used to study the film formation and lubricant flow. To enable the use of the conventional methods it is necessary to apply a thin reflective layer on the non-reflective surface. This work evaluates the current literature dealing with the coating of polymeric materials. A method was chosen based on the analysis of the currently available technologies, which is used to apply a thin reflective layer on the polydimethylsiloxane sample. This part is followed by a feasibility study to clarify the effects of the coating on friction processes. This work can significantly contribute to the field of compliant contacts, especially in terms of clarifying the mechanisms of lubrication.
Methods of coating and coatings analysis
Rudy, Veronika ; Mouralová, Kateřina (referee) ; Prokeš, Tomáš (advisor)
The thesis deals with the coating of cutting tools. It summarizes the types of material used to create cutting tools, the characteristics of the main coating methods, the way tools are treated before coating and methods of testing the physical properties of coatings. The practical part contains the description of coating deposition on interchangeable cutting blades, where two types of coating were tested (SHM1 and SHM2). Furthermore, their mechanical and physical properties were tested. The analyzes used were adhesion and cohesion tests, coating thickness and hardness along with the chemichal composition.
The manufacturing process of the ball joint
Petříček, Vít ; Majerík, Jozef (referee) ; Kalivoda, Milan (advisor)
This bachelor thesis deals with the general introduction of the component "ball joint", its construction requirements and production. Two technological processes for the production of a particular spherical pin were selected and presented, namely the production of a cold-forming and a machining. Both methods are compared with each other and their suitability for serial production is assessed. In the final part there is generally shown the technological process of production of the ball pins of the car control.

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