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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.
611

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.
612

Volba vhodných řezných podmínek pro obrábění hlavňových ocelí / Prediction of suitable cutting conditions for machining of main steels

Beneš, Ondřej January 2018 (has links)
In this thesis is described machining of barrel steels and determination of the most suitable cutting conditions for this process. In the theoretical part was characterized cutting process and explained problems of VBD wear, chip formation and roughness of the surface. There were also explained most common cutting materials and in the last part were described CVD and PVD coating methods. In the experimental part was measured force load during turning. There was also tested eight carbide cutting inserts from SECO TOOLS. During the tests were measured additional surface roughness values and taken chip samples as well. From the evaluated load force data were determined optimized cutting conditions for machining barrel steels and most suitable type of cutting insert.
613

Měření nerovností povrchů vozovek geodetickými metodami / Pavement Roughness Measurement with Use Geodetic Methods

Gašparík, Michal January 2016 (has links)
The issue of this diploma thesis is measurement of pavement roughness with an alternative means of data acquisition and evaluation by geodetic methods. In the beginning there is an overview of current state of actual roughness measurement methods. The main work is concerned with data acquisition with passive reflection of the laser rangefinder and laser scanner and standard deviations that arise in measuring on asphalt and concrete road surfaces. The aim of the work is to formulate the process of data acquisition, specification of standard deviations in the process of measuring, evaluation of pavement roughness according to ČSN 73 6175 standard, and their applicable graphic interpretation. Based on the analysis of accuracy of the methods applied, their usefulness is evaluated in comparison with the straightedge test.
614

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.
615

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.
616

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.
617

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.
618

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.
619

Technologické podmínky aplikace supertvrdých řezných materiálů / Technological conditions application superhard material

Jelínek, Adam January 2013 (has links)
Diploma thesis is intended on the aplication of superhard cutting material which contain polycrystalline diamond and cubic nitro nitride boron. There are solved area of using superhard cutting materials, optimal cutting conditions, technilgic – economic view and reached parameters during cutting (roughness, geometric tolerance). The aim of this is to define what are an achieved parameters
620

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.

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