Měření a analýza nerovností povrchů vytvořených hydroabrazivním a laserovým dělením z hlediska materiálu a mechanismu desintegrace.

Abstract

Presented PhD thesis is focused on evaluation of topography of cutting walls created by abrasive water jet and CO2 laser. The evaluation of topography of cutting walls was performed on engineering materials (steel S235JRG2, titanium ASTM B265-99, stainless steel AISI 304 and aluminum alloy AlMg3). Based on the plan of experiments, manufacturing of samples has been realized. All sampleswere prepared using AWJ and CO2 laser. Different technological conditions were used for realization of cuts. A number of different qualities of surfaces were obtained using various cutting conditions. The topography of tested samples was measured by an optical profile meter MicroProf FRT. Analyses were focused on the distribution of height roughness parameters of waviness through depth of the cut wall. Subsequently, relations between parameters of waviness, material properties and technological conditions used for samples preparation were studied. The theoretical part of PhD thesis is focused on the current state of use of AWJ and CO2 laser technologies in engineering applications of cutting of materials. This part is followed by an extensive chapter focused on the interpretation and description of the surface structure and methods of their evaluation. Conclusion of the theoretical part is devoted to the theory of study of mechanical properties of surface layers using instrumented indentation methods. The practical part of thesis is focused on: experimental preparation of tested samples, measurement methodology for evaluation of cutting walls, study of the mechanical properties of the materials and analysis of obtained data. Based on the theoretical knowledge and realized measurements, basic mathematical – empirical model has been developed for prediction of parameter waviness in relation to technological, geometrical and material parameters of cut. The proposed model is based on the results of the measurements and it can be applied for both cutting technologies. In conclusion of PhD thesis, the methodology for setting the optimal technological conditions of cut is proposed. The methodology is based on the principle of prediction graphs and equations, which allows to determinate required quality of cut in relation to topographical parameters of waviness, main technological parameters of cut and operation costs for running technology.