Proposition of a solution for the setting of the abrasive waterjet cutting technology

The submitted paper aims to clarify the abrasive waterjet technology, particularly from the point of view of produced surface topography. It provides a new insight into the deformation process caused by the effect of abrasive waterjet and into the possibilities of using the surface topography for solving the issues of optimization of the process. The subject of study is a system of cutting tool, material and final surface topography and optimization of their parameters. The cutting or disintegrating tool of abrasive waterjet technology is flexible. The trajectory of its cut traces is strictly determined here by disintegration resistance at critical moments of tool-material interaction. The physico-mechanical character of the interaction within the cut will manifest itself in the final surface condition. This process can be re-analysed by measuring the selected elements of topography and roughness on the final surface, namely depending on the depth of the cut, technological parameters of the tool and mechanical parameters of the material. The mentioned principle is the basis of the presented solution. It lies in the analytical processing and description of correlation interrelations between set technological and measured topographical quantities in relation to the depth of cut and the type of material.Web of Science13528527

Method of maintaining the required values of surface roughness and prediction of technological conditions for cold sheet rolling

The paper is based on results obtained from topography of surfaces of sheets rolled from deep-drawing steel of the type KOHAL grade 697, non-alloy low-carbon structural steel EN 10263-2:2004 and aluminium. The presented results document correctness of the assumption that the rolling force Froll increases with the increasing reduction Δh and the quality of the rolled surface is improved at the simultaneous increasing of strength of rolled sheets and the decreasing of size of structural grains. The experiment was performed on the two-high rolling stand DUO 210 SVa, which enables only non-continuous technology in contrast to the rolling mill with continuous reduction on one sheet in several degrees on rolling trains, in consequence of which the obtained height parameters of the section are in close correlation with the predicted dependence. Contribution of the work consists in the creation of a mathematical model (algorithm) for predicting technological parameters of the two-high rolling stand DUO 210 SVa at change of the absolute reduction Δh, for example for a deep-drawing steel of the type KOHAL grade 697 and non-alloy lowcarbon structural steel PN EN 10263-2:2004 and aluminium, and also in the development of a method of calculation applicable to any material being rolled in general, because the authors have found that various materials can be differentiated by a derived analytical criterion IKP. This criterion is a function of ratio between the modulus of elasticity of reference material and that of actually rolled material. The reference material is here deep-drawing steel of the type KOHAL grade 697. Verification was carried out by measuring changes of final surface roughness profile and final strength of rolled sheets of the stated materials in relation to reductions and those were compared with theoretically predicted values. It is possible to identify and predict on the basis of this algorithm an instant state of surface topography in respect to variable technological conditions. On this basis it is then possible to calculate and plot individual main technological parameters.Web of Science14315114

System for Monitoring and Control of a Technological Unit

Import 31/08/2009Diplomová práce se zabývá problematikou systémů určených k monitorování a řízení technologie. Konkrétně monitorováním a řízením elektrických pohonů. První část je věnována úvodu k problematice asynchronních motorů a způsobům jejich řízení. Následuje popis reálného modelu umístěného ve školní laboratoři. Cílem práce bylo sestavit, zapojit a zdokumentovat úlohu řízení a monitorování asynchronního motoru pomocí frekvenčního měniče a nadřazeného systému (PLC). Pozornost je věnována popisu jednotlivých komponent, jak hardwaru, tak i softwaru. Jejich použití a konfiguraci. Další část práce se zabývá tvorbou programů pro PLC a následnou vizualizaci. Výsledný systém představuje využití těchto prostředků v praxi a měl by sloužit pro výuku studentů.Diploma thesis deals with a system for monitoring and control of technologies, specifically monitoring and control of electro drives. The first part is introducing the asynchronous drives and methods for their control. Furthermore, a real model from a department laboratory is described. A goal of this work was to build and configure system architecture and to document a task for control and monitoring of asynchronous drive by frequency converter and a superior system (PLC). The focus is placed on each component description, hardware and software, their use and configuration. Programs created for PLC and for visualization are also described. Designed system represents an application of these software and hardware means in industrial automation and will help students during their classes in a laboratory.352 - Katedra automatizační techniky a řízenívýborn

Programming of ASP.NET 2.0 web applications

Import 20/08/2007Prezenční352 - Katedra automatizační techniky a řízen

Spectral analysis of data acquired using optical measurement of surface topography

Disertační práce se zabývá dvourozměrnou Fourierovou transformací a možnostmi jejího využití pro analýzu a hodnocení dat získaných měřením topografie povrchu obráběných materiálů. Práce stručně popisuje princip měření topografie povrchu a metody používané k vyhodnocení naměřených dat, které jsou v současnosti obsaženy v technických normách. Největší část práce je věnována dvourozměrné Fourierově transformaci, jejím vlastnostem, metodám výpočtu, dále také přehledu typů nerovností povrchu a jejich zobrazení ve dvourozměrných spektrech včetně verifikace teoretických předpokladů na reálném měření. Navržená metoda automatizovaného vyhodnocení vlastností povrchu z vypočtených dvourozměrných spekter spočívá v prahování spekter a sledování změn oblastí vysokých a nízkých frekvencí. Navržené metody byly ověřovány nejprve na datech naměřených profesionálním optickým profilometrem a poté také na sestaveném funkčním vzorku kamerového systému.This dissertation thesis is focused on two dimensional Fourier transform and possibilities of its use for analysis and evaluation of data acquired from measurement of surface topography. Principles of surface topography measurements are briefly described as well as methods used for processing of the topographical data which are currently included in technical standards. The main part of this thesis is dedicated to the two dimensional Fourier transformation, its properties and calculation methods. It also focuses on an overview of surface irregularities and its visualization in the two dimensional spectral maps. Theoretical assumptions were verified using practical measurements. The proposed method for automated evaluation of surface properties is based on the two dimensional Fourier spectral maps. It includes thresholding of spectral maps and evaluation of changes in the areas with low and high frequencies. The proposed methods were first tested on data acquired using professional optical profilometer and after that also using camera system designed for this purpose.352 - Katedra automatizační techniky a řízenívyhově

Analysis of periodicities in surface topography of cold rolled sheets using data captured by camera system

A method for surface analysis of cold rolled sheets is proposed in this paper. The approach is based on a low-cost specially built camera system followed by spectral analysis of the data captured from metal surfaces. The focus is on the changes in the surface topography caused by cold rolling with emphasis towards periodicities in the processed surface. Angular profile of the spectrum is calculated and used to display periodicities in surface topography and show their direction. The results obtained by using the proposed system were compared with results obtained from the optical profilometer MicroProf FRT. The experiments show that cold rolling creates marks on the surface of the material, which represent periodicities that can be effectively detected by the proposed method and camera system. Even though the camera system is not able to measure precise surface roughness, it is able to detect periodicities and the results of spectral analysis are comparable with the results from the optical profilometer.Web of Science20314914