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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
291

Optimalizace obrábění keramických polotovarů / Milling optimization of ceramic blanks

Ráčková, Jana January 2018 (has links)
The master thesis deals mainly with the optimization of machining of ceramic semi-finished products from ZrO2 and Al2O3. The first part with literary research, which describes the steps of the technology of forming ceramic bodies, especially the gelcasting method. The thesis describes possibilities of milling of ceramic materials using CNC technology. The thesis describes the dependence of acquired roughness on bodies and used machining strategies. The best roughness parameters on ZrO2 samples were obtained after they were calcined at 900 ° C, while the lowest roughness was obtained on the samples in the unprotected state for the Al2O3 samples. Samples machined with a spherical milling cutter showed surface roughness Ra = 1 m for ZrO2 and Ra = 1.3 m for Al2O3. It also describes the possibility of machining sharp-edged shapes and fine details where the best results are achieved on ZrO2 samples engraved at 900 and 1100 °C. Tool wear was particularly important when machining samples of Al2O3 ignited at temperatures above 800 °C.
292

Metodika testování nástrojů s břity z cermetů při soustružení / Tool wear testing method of cutting tools with cermet cutting edges in turning

Koppová, Aneta January 2020 (has links)
The diploma thesis deals with the analysis of the wear of tools fitted with cermet cutting edge. The first part is focused on the theoretical aspects of the problem, which are applied in the practical part. The aim was to perform cutting tests in which carbon steel was turned under selected cutting conditions. Tool wear during turning and the quality of the machined surface were monitored. Machining continued until the selected wear criterion reached the limit value. Two different cermets were tested and the measured data were the basis for the analysis of the wear of the tool edges and the determination of the tool life.
293

Optimalizace výrobního procesu přesného obráběného dílu / Optimization of the production process of a precision machined part

Kolomý, Štěpán January 2021 (has links)
This master‘s thesis deals with optimization of cutting conditions when machining of precise parts in mass production. In experimental part of this thesis is a comparison of the roughing tool with indexable cutting inserts with the new implemented milling cutter. Tool wear of both roughing tools has been analysed. The surface roughness analysis after machining with the face milling cutter was performed. The output of this work is to obtain optimal cutting conditions to gain a minimum surface roughness.
294

Composition Effects on Sheen and Spread Rate of an Interior Flat, One Coat Latex Paint Formulation

Christensen, Dana James, II 01 August 2015 (has links)
Interior flat, white latex paint is a common coating applied to walls around the world. Development of a coating with one coat hide capability is a pinnacle achievement for paint formulators as it has the potential to save consumers both time and money. One coat paints already exist on the market, but they are limited in color, coverage, and often have many disclaimers. Work done was part of a project initiated by ChemoursTM Titanium Technologies. The goal of the project presented in this article was to create an interior flat, white latex paint that yields a spread rate of greater than 400 ft2/gal., which is advertised by many below critical pigment volume concentration (CPVC) commercial paints. In order to achieve this goal, an above CPVC paint with a high TiO2 content was created and continuously improved. Improvement of the formulation involved numerous experimental variations including adjustments to the hydroxyethylcellulose (HEC) molecular weight, dispersant chemistry, latex chemistry, TiO2 concentration, extender package, and rheology modifier type. The sheen value, relative light scattering, and spread rate were the main measurements conducted in order to judge formulation improvement. Complications with the spread rate procedure forced its adaptation in order to collect less variable data with the high density, shear thinning formulations. It was found that shorter opacity charts yielded more precise spread rate data than the longer opacity charts. An attempt at correlating rheology with sheen development resulted in the conclusion that the pigment and extender particle package is the greatest driving factor behind sheen reduction. The rheology modifier type and dispersant chemistry did not affect the flatness of the paint nearly as much. A Keyence VR-3000 series One-Shot 3D Measuring Macroscope was used to show that surface roughness does not directly correlate to the sheen value when a number of flat paints with different sheens were analyzed. This project is an ongoing effort and the information contained in this document will substantially help future development.
295

Hodnocení čelního těsnícího provedení povrchu pomocí charakteristik textury povrchu / Assessment of face seal performance based on surface texture characteristics

Kučera, Pavel January 2008 (has links)
Diploma work dealing with assessments facing the sealing fulfilment surface describes and compares surface topography with the aim of analyzing the most significant characteristic parametrs and factors influencing seal and functional reliability in a decisive way. The most suitable parametrs of sealing which were designated : material ratio Rmr and parametrs Rpk, Rk and Rvk.
296

Studium vlivu parametru elipticity na rozložení tloušťky mazacího filmu / Study of the effects of ellipticity parameter on lubrication film shape

Pavlík, František January 2011 (has links)
Diploma thesis deals with elastohydrodynamic lubrication of point contacts, which surfaces are influenced by topography and velocity vector of one rubbing surface is misaligned. Author summarizes knowledge of previously published research articles, which fundamentally enrich current state of knowledge. Diploma thesis contains experimental measurement results of the film thickness and the way of lubrication film formation in elliptical contact for different ellipticity parameters, kinds of rubbing surfaces and angles of the velocity vector. New findings have helped to better understand the behaviour of highly loaded lubricated contacts taking place in machine components and completed the current state of knowledge with results that can be used in next thorough study of this issue.
297

Volba a optimalizace řezných podmínek pro progresivní výrobní technologie / Data selection and optimisation of cutting conditions for progressive production technologies

Caha, Tomáš January 2015 (has links)
This thesis contents theoretical description of methods for choosing and optimization of cutting conditions for progressive machining technologies. Especially it is concerned on CNC machining. The aim of experimental part of work is to set cutting conditions and simultaneously to achieve the most economical solution under current production conditions of the company. The product must also comply with required quality, roughness of the surface and geometrical precision.
298

Výroba složitých tvarových ploch pomocí CNC/Heidenhain iTNC 530 / Production of sculptured surfaces with CNC/Heidenhain iTNC 530

Břínek, Martin January 2014 (has links)
The diploma thesis is focused on the milling strategies and their suitability for the production of complicated sculptured surfaces using a three-axe milling center and the operation system Heidenhain iTNC 530. The behavior of the tools and the results of the individual milled samples were monitored under changing milling strategies during the experiment. The outcomes of the experiment were seven milled samples and an assessment of the effect of the Machine – Tool – Workpiece system toughness. In addition, the suitability of the milling strategies were evaluated in consideration to the quality of the milled surface and the production time.
299

Moderní dokončovací metody obrábění vnějších povrchů / Modern cutting finishing methods of outer surfaces

Laňka, Lubomír January 2014 (has links)
This master`s thesis is focused on modern cutting finishing methods of outer surfaces. In the first part the cutting finishing technologies of outer surfaces are analysed, which is followed by a description of modern finishing methods from the fine machining up-to the nano-machining. The experimental part includes the analysis of surface roughness during front turning of a dural disc and the study of magnitudes of forces during its longitudinal turning. The thesis contains technological-economic evaluation of the achieved results.
300

Analýza procesu výroby čerpadel, návrh a optimalizace nového postupu ve firmě Antreg, a.s. / Analysis of the pump production, desighn and optimalization of the new proces at company Antreg, a.s.

Šeniglová, Hana January 2016 (has links)
This master’s thesis deals with the process of production of oil pump at the company Antreg, a.s. The purpose of the thesis was to design a new technological process without grinding. The goal was achieved by an experiment. The necessary measurements were taken on the front part of the oil pump box. Measurements are described and evaluated in this thesis. As a next step, optimal technological process was applied to other parts of the oil pump box. An economic evaluation was carried out for a selected technical process.

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