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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.
21

A study of the cutting performance in multipass abrasive waterjet machining of alumina ceramics with controlled nozzle oscillation

Zhong, Yu, Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW January 2008 (has links)
An experimental investigation has been undertaken to study the depth of cut in multipass abrasive waterjet (AWJ) cutting of an 87% alumina ceramic with controlled nozzle oscillation. The experimental data have been statistically analysed to study the trends of the depth of cut with respect to the process parameters. It has been found that multipass cutting with controlled nozzle oscillation can significantly increase the depth of cut. Within the same cutting time and using the same cutting parameters other than the jet traverse speed, it has been found that multipass cutting with nozzle oscillation can increase the depth of cut by an average of 74.6% as compared to single pass cutting without nozzle oscillation. Furthermore, a multipass cutting with higher nozzle traverse speeds can achieve a larger depth of cut than a single pass cutting at a low traverse speed within the same cutting time. A recommendation has been made for the selection of appropriate process parameters for multipass cutting with nozzle oscillation. In order to estimate the depth of cut on a mathematical basis, predictive models for the depth of cut in multipass cutting with and without nozzle oscillation have been developed using a dimensional analysis technique. The model development starts with the models for single pass cutting which are then extended to multipass cutting where considerations are given to the change of the actual standoff distance after each pass and the variation of kerf width. These predictive models has been numerically studied for their plausibility by assessing their predicted trends with respect to the various process variables, and verified qualitatively and quantitatively based on the experimental data. The model assessment reveals that the developed models correlate very well with the experimental results and can give adequate predictions of this cutting performance measure in process planning.
22

Racionalizace malosériové výroby výpalků v podmínkách firmy PARS Nova a.s. / Rationalization of small-lot production of slops in conditions of company PARS Nova a.s.

Jurka, Pavel January 2008 (has links)
Analysis of the technological possibility ray methods of protoplasm, laser and water jet on the part of needs company Pars Nova a.s.. Propsal concrete of unconventional method. Process layout and exigencies of working designed method. Security and ecological diversification of designed method. Technical – economics evaluation contribution designed of unconventional technology.
23

Technologie paprskového řezání / Cutting beams technologies

Kocman, Luděk January 2013 (has links)
The diploma´s thesis deals with cutting beams technologies. It shows the current knowledge of these cutting methods, their possibilities and applications. The practical part rates benefits of replacement water jet with laser from economic and technological perspective.
24

Řezání abrazivním vodním paprskem / Abrasive water jet cutting

Midrla, Zdeněk January 2013 (has links)
This master thesis is consisted of literature search and practise part with focusing on the theme of abrasive water jet cutting. Introductory chapters deal with various methods and principles water jet cutting. Following chapters deal with quality of cutting surface by abrasive water jet cutting. After these chapters is introduced machine equipment of water jet cutting technology. At the end of this theoretical part are listed advantages and comparison with other unconventional technologies. In the practical part is solved design of machinery with regard to manufacturing technology of component flange in series 630 000 pieces per year. Last chapter describes economic evaluation of production.
25

Nekonvenční metoda obrábění vodním paprskem / The unconventional Method of Cutting Water Jet

Prax, Ondřej January 2011 (has links)
The master thesis contains a literature search dealing with the unconventional technology of water jet cutting. The first part is aimed to description of the water jet technology and shows the possibilities of controlling and awarding data for cutting. Follows the chapter about the influences of the input parameters to a surface quality and machining accuracy. The thesis also giving an account of ecological factors of the water jet cutting. The description of the whole technology for production of the sprocket is a part of the thesis. The last part of the thesis is solving the economics of the water jet cutting technology, especially for production of the sprocket with comparing dependency of the cutting conditions.
26

Technologie výroby vymezovací podložky / Manufacturing technology of the distance washer

Dvořák, Jiří January 2011 (has links)
This master’s thesis has been elaborated as a part of master’s studies of engineering technology M2I-K, major in M-STM – Engineering technology and industrial management and deals with the problem of a transition to a self-production of previously purchased distance washers. Distance washers were purchased in six different types of similar shape, each type in four different thicknesses. One of these types was chosen as a representative for this master’s thesis. We shall explore the possibilities of self-production with the emphasis on economical validation of the transition. The distance washer is a flat part, the intermediate being sheet metal. Technologies considered for manufacturing the washers correspond to the technical facilities and equipment available at the production hall of the company this project is planned for. The company possesses technology for CO2 laser cutting, cutting by CNC punching machine and cutting in the punching tool. To provide a complex overview we shall also enquire into cooperated technologies such as water jet and plasma cutting, oxy-acetyleny cutting and CNC working. All options are evaluated with regard to the production expenses and lead to a most economically plausible method of manufacturing or, if need be, give reasons for going back to purchasing the part from the current supplier.

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