Browsing by Author "Žižka, Jan"
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- ItemCutting process monitoring by means of acoustic emission method part I - New approach of acoustic emission sensor and part 11 - Transformation of acoustic emission into audible sound(Technical university of Liberec, Czech Republic, 2006) Žižka, Jan; Hána, Petr; Hamplová, Lenka; Motyčka, ZdeněkDevelopment of modern society is converging to a status where many human actions can be performed by machines. To achieve production without human intervention, machines require artificial receptors. Data gathering for processing and analysis of signals, together with determination of feedback reactions can be achieved by a suitable decision maker unit. A sensed value suited to this so-called intelligent sensing process would be the acoustic emission signal. In the case of intelligent cutting tools this would require miniature highly sensitive sensors integrated into the cutting tool body. Part I of this paper deals with the possibility of practical usage of the piezoelectric properties of copolymer foils for the acoustic emission sensor as a transducer of a mechanical surface wave into electrical signal. Part II of the paper deals with the most fundamental requirement for monitoring of cutting conditions during machining, i.e. excellent processing of measured data. Data obtained from machining process obtained by means of acoustic emission sensors, as discussed in the first part of this article, have high-frequency and continuous character of a white noise. These data are very difficult to process. New apparatus for transformation of acoustic emission into audible sound in the workplace is presented. The first stage of processing is by listening to transformed data it is subjectively possible to recognize differences in audible spectrum, corresponding to different states of the cutting tool. The second step is visualization of the differences via the fast Fourier transform (FFT) in the spectrum graphic chart.
- ItemNávrh a ověření experimentální sestavy na měření teplot při soustružení.(Technická Univerzita v Liberci, 2006) Honzík, David; Žižka, JanThis bachelors thesis gives information about the temperature measurement during cutting process. The work is gained on analysis of the temperature sensor and it´s integration into a turning tool. The design of new conception of thermocouple localization into the holder nose is given. The technology of tool processing and sensor assembling is shown. The tool new prototype were used for verification tests and all system function.
- ItemNávrh a ověření experimentální tenzometrické sestavy na měření řezných sil a deformací při soustružení(Technická Univerzita v Liberci, 2007) Linhart, Tomáš; Žižka, JanThe diplom thesis summarizes information about measurements of cutting forces and deformations during turning when using so called intelligent lathe tool. Measurements are based on using two strain-gauge half bridges and sampling is done by Spider 8 measuring equipment. Lathe tool prototype has been newly designed with integrated deformation sensors and temperature sensors in the body. The thesis describes tool manufacture, sensors installation and their overall connection to data logger and measuring device. Lathe tool prototype has been used for system validation test and for subsequent cutting force measurement.
- ItemPorovnání převodníků akustické emise pro účel obrábění(Technická Univerzita v Liberci, 2006) Hamplová, Lenka; Žižka, JanThis bachelor thesis is intent on both the comparison of different kinds of the acoustic emission transducers and the possibility of their application for cutting process sensing. The work is also focused on the PVDF film and piezoceramic transducers assembling into the tool holder shank and its functionality in the turning process.