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Abstract:Paper describes the mechanism of vibration of a minimal automotive disc brake model which can lead to unwanted effects known as brake Noise Vibrations and Harshness (NVH). Stick-slip frictional effects are mathematically described by simplification of physical assumptions. Self-excited vibrations due to stick-slip and also stability conditions are defined using a 1 degree of freedom mechanical system. Non-Coulomb nonlinear behavior of the friction force with negative slope is considered. Response is obtained by the numerical solution of ordinary differential equation.

Abstract. Using of cutting inserts is currently a normal part of the manufacturing process. The article deals with the tool wear evaluation of selected inserts for turning by electron microscopy. Use of electron microscopy helps closer analysis of machining consequences for these plates, because the microscope images captured with the electron microscope have a greater depth of sharpness and can display the examined object with greater plasticity. It is another way to explore objects and extends the possibilities for obtaining large quantities of information. Electron microscopy is possible to be used for getting better information about toolwear after machining, for example, too. One of the possible usages during the research is in the area of toollife of cutting inserts, which is realized at the Faculty of Production Technology and Management of Jan Evangelista Purkyně University in Ústí nad Labem. As part of this research various analyzes were also carried out. Part of such research was to analyze the resulting tool wear of the used inserts after turning of selected material also by electron microscopy, specifically the SEM analysis. The SEM analysis can show more and more what in the surveyed area might happen in comparison with conventional microscopy. Images are sharper and more stereoscopic and some aspects are more noticeable. That is why SEM was used as a complementary analysis method throughout this research. As an experimental material hardened steel class 16 343 according to the CSN 41 0002 has been used. The experimental material was turned on the three-axis CNC lathe DOOSAN Lynx 220L with the control system FANUC.Keywords: tool wear, electron microscopy, tool life. IntroductionAt the Faculty of Production Technology and Management, which is part of the Jan Evangelista Purkyně University in Ústí nad Labem several research projects are carried out. One of them is research in the area of tool life of cutting inserts, because using of cutting inserts is currently a common part of the manufacturing process and it is very interesting for production companies. As part of this research various analyzes were also carried out. One of these was analysis of tool life of experimental inserts by the SEM analysis, which is available at FPTM JEPU [1][2][3].The SEM analysis was used to supplement the final examination of the insert tool wear after machining.The abbreviation SEM means a scanning electron microscope. This microscope is working with a narrow electron beam. To formation of images primary and secondary electrons are used backscattered from the sample surface. These electrons are formed by the interaction of atoms of the sample with electrons of the electron beam. The detector receives and processes the electrons so as to obtain a sharp image of the sample surface. Rather than a traditional optical microscope its advantage is a large depth of focus and the ability to get more magnification [4][5][6].The SEM analysis can show more and more what in the surveyed area might happen, in comparison with convent...

Using of cutting inserts is currently a normal part of the manufacturing process. The article deals with the tool wear evaluation of selected inserts for turning by electron microscopy. Use of electron microscopy helps on closer analysis of machining consequences forthese plates, because the microscope images captured with electronmicroscope have a greater depth of sharpness and can display examined object with greater plasticity. It is yet another way to explore objects and extends the possibilities for obtaining large quantities of information. These analyzes were realized in other experiments performed at the Faculty of Production Technology and Management of Jan Evangelisty Purkyně University in Usti nad Labem. As a experimental material the hardened steel class 16 343 according to CSN 41 0002 has been machining.

The evaluation of disk brake squeal is nowadays performed using Finite Element Model. In this standard procedure the thermal effects are omitted. The omission is done because of long computing time of fully coupled brake system thermo-structural transient analysis. This paper is presenting an effective uncoupled thermo-structural FEM procedure. This method is applied on a pin-on-disc system and its time effectiveness is compared to standard full coupled transient analysis.