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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.
31

Analýza opotřebení řezných nástrojů při soustružení konstrukční oceli / Analysis of cutting tool wear while turning construction steel

Kudela, Jan January 2019 (has links)
The goal of the thesis is wear analysis of cutting inserts used for machining 42CrMo4 steel. Theoretical part of the thesis contains comparison of turning and milling machining processes, machining methods for ball screws made of 42CrMo4 and description of experimental methods of tool wear analysis. Experimental part of thesis contains methodology of cutting inserts wear measurement for chosen machining method. The following testing is focused on cutting insert wear as well as workpiece surface analysis. Thesis is finished with processing of measured data and overall evaluation of achieved results.
32

Zkoušky řezivosti VBD při soustružení konstrukční kalené oceli / Cutting Tests of Insert for Turning Structural Hardened Steel

Šolc, Michal January 2020 (has links)
The thesis deals with the wear of replaceable inserts during the turning of structural hardened steel. The theoretical part describes a brief characteristic of turning technology, force loading on tools and tools used in turning. Moreover, it contains an analysis of the chemical composition of the machined material, its microstructure and microhardness. Machines and equipment used for the experiment and their specifications. The experimental part of the thesis describes the method of measuring and evaluating of tool wear, followed by the cutting tests themselves, documenting of the result and their evaluation. The conclusion of the thesis is the processing of measured data, the evaluation of achieved results and the proposal of further steps to improve the process.
33

Polohování naklápěcí hlavy frézovací multifunkčního obráběcího centra s vodorovnou osou vřetena / Positioning of the tilting head of a milling multi-purpose machining center with a horizontal spindle axis

Grepl, Martin January 2020 (has links)
The thesis deals with the positioning of the tilting head of the multifunctional milling centre in three axis. The aim of the thesis is to design a multifunctional milling machine centre with a horizontal axis of the spindle in cooperation with Bc. Ľubomír Vazovan, Bc. Ján Rapčan a Bc. Tomáš Hynšt, who are working on the issues of the headstock, automatic tool change and palletization. The thesis also contains proposals of certain options and their subsequent evaluation by the multicriterial method PATTERN. The resulting construction is complemented by calculations of the main construction nodes.
34

Elektromechanická alternativa hydraulické lineární tahové jednotky / Electromechanical alternative of linear hydraulic tractive unit

Hammer, Jaroslav January 2008 (has links)
In this diploma thesis is accomplished description of existing condition of decorating linear tractive unit. Analysis of safety requirements for linear tractive unit is also accomplished. Eligible construction concept of frame of electromechanical linear tractive unit is chosen. Selection and calculation of ball screw and nut is made also with draft of its eligible support . Choose of eligible engine and clutch for gearing of engine torque from engine to the ball screw is done too. Further is designed eligible concept of gearing of the rotary motion of ball screw to straight motion of bottom pulley block, which now interacting with upper firm pulley block provides lifting of tensile rod with coulisse.
35

Servoelektrická upínací jednotka / Servodrive Clamping Unit

Šťastný, Libor January 2009 (has links)
Design servodrive clamping unit with pneumatic or mechanic multiplier. Unit has be instrumental to strength clamp parts in tension technical machines. Frame unit’s is complicate from massive and movable clamping board and is self-supporting. Unit has be solution like incorporated modulus. Target is proposal main driving period for movable clamping board. Work up proposal constructional solution, drawing listings, production drawing of the three engaged part of, BOM. Computational report must include calculations drives, constructional knots and their verification and further needed strength calculation and analyses. Proposal treatment tribotechnical knots. Analysis construction from standpoint safety in operation according to NV24/2003 and analysis safety hazards. Part of work must be and economic analysis resultant solution.
36

Konstrukce multifunkčního obráběcího centra / Design of multi-functional machining centre

Sedlák, Pavel January 2011 (has links)
This master thesis deals with the construction of multi-functional machining centre. The theoretical part describes the history of lathes, trends in production of lathes and individual machine parts. The practical part is the structural design of the spindle with positioning in the C axis, the second spindle (including drive in Z axis) and the turret (including drive in the X and Z axis). A 3-D model of the entire lathe assembly modeled in Autodesk Inventor 2010 is also included.
37

Manipulační nástrojová jednotka / Automatic Tool Changer

Láznička, Petr January 2015 (has links)
The thesis is focus on design solutions of automatic tool changer for CNC vertical milling machine SLV 300 in cooperation with the design company IMC/Engineering s. r. o. The main goal of theses is the creation of several design variants based on the critical research of similar machinery and the subsequent choice of the most appropriate solution. The assessment of the various options is done with amount of the changes caused on the existing design of the machine. It is essential the suitability of the solution from the perspective of the customer's company SolidVision s. r. o. Design solution is being designed for the possibility of a presentation device with unique features in its class, which is meant to be a simple maintenance free design with the possibility of easy service access For the chosen solution of the automatic tool changer are by calculation verified by the most exposed part of the device. In the thesis is also design documentation, for a better understand of the design solution.
38

Thermal Analysis of Wave Energy Converter : Developing a Compact CHT Model for Operational Insights

Jidbratt, Jakob, Leckström, Joel January 2023 (has links)
Climate change is a critical global issue that continues to shape the way we understand and interact with the world around us. It is discussed more than ever before, especially in politics. To slow down the temperature rise of our planet, decreasing the amount of green house gas emissions produced by our way of living, industries, and the production of energy is necessary. Ocean Harvesting Technologies (OHT), a company from Sweden based in Blekinge, is currently developing a new iteration of renewable, wave energy converters (WEC) that they claim to be ecient from both an energy and cost perspective. A new prototype is in development where thermal and fluid characteristics inside the WEC during operation, are important aspects that need to be evaluated. This project is aimed to develop a computational simulation model of the WEC and perform simulations in order to evaluate the cooling and heating performance of the current model that is under development. The methodology used for this project was divided into three stages to streamline the work: steady-state stationary conjugate heat transfer(CHT) simulations, and transient airflow simulations with motion and compressible air, that are combined into a full-system transient CHT model for operational conditions. CAD models and delimi- tations were provided by OHT and the model was broken down, simplified and assessed to begin the work. The computational software used for the simulations in this project was STAR-CCM+ and the complete process of pre-processing, simulation setup/run and post-processing was executed using the same software. To simulate the fluid and the oper- ational motion of the WEC, the Overset mesh methodology was used, and to resolve the turbulent flow, URANS k! SST was used in the solver. The thermodynamic simulations were initially set up and simulated in two sub-models in order to speed up the method development and to get an early indication of the performance of the WEC. The first sub-simulation handled the compressible air together with the Overset mesh motion while the second simulation aimed to model the thermodynamics of the generator components, ball screw, and other solids. Since OHT is in a relatively early development phase, no experimental data could be used for validation, however, data sheets for generator com- ponents and simple handbook calculations were used to validate the simulation models performance. The sub-simulations resulted in an ecient simulation strategy and a lot of knowledge and understanding of the system performance was gained to implement in the full-system model The final outcome of this thesis work was a complete CHT model that showed the ca- pability of running several hundreds of seconds of operational time while producing a significant amount of performance data such as temperature profiles of critical parts, air pressure/temperature fluctuations, and drag losses of the complete WEC. Furthermore, the sub-simulation models can be used individually as stand-alone models in order to op- timize the system on a component level, e.g., drag losses from the generator components during motion.
39

Konstrukční návrh lineární osy pro těžký obráběcí stroj / Design of linear axis for heavy machine tool

Horák, Miroslav January 2019 (has links)
This diploma thesis deals with the design of linear axis for heavy machine tool. The thesis describes the definition of heavy machine tool and its basic construction nodes. The next chapter describes the components of the linear feed assemblages, the basic principles of use and their advantages and disadvantages. On the basis of this research part there are selected variants of the solution and in the last part of the thesis there is a design of the axis X of the gantry machine tool. Part of the work is a 3D model of the proposed feed assemblages and part of the drawing documentation.
40

Náhon posuvové souřadnice portálového obráběcího centra pomocí pastorku a hřebene / The drive of the feed coordinate portal machining center using a rack and pinion

Bartoš, Michal January 2019 (has links)
This diploma thesis deals with the design the drive of the feed coordinate portal machining center using a gear rack and pinion. The thesis contains researches from the area of CNC machining centers for non-rotating parts and sliding linear systems. Market analysis of portal machining centers of type of lower gantry with a gear rack and pinion was done. Furthermore, several design variants are proposed in terms of positioning the drive on the machine. These variants were further compared and the best option was selected for the specified machine. Subsequently, the technical calculation of the drive is performed and individual parameters and structural elements are proposed. The thesis also includes a 3D model of the proposed variant and the required drawing documentation.

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