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The need to increase productivity and cost-effectiveness of gear cutting of cylindrical gears with oblique teeth creates favorable conditions for the development of research in the field of tribology and the increasing application of tribological knowledge in industrial practice. Improving the gear cutting process by hob milling is important and useful for both gear manufacturers and hob milling tools manufacturers. Increasing productivity and increasing of the quality of serration are the basic directions of improving the process of gear cutting by hob milling. Technological parameters significantly affect the wear of cutters and taking into account the parameters for defining the economy of the process affect the achievement of optimal parameters of the cutting regimes. Based on experimental research, the paper presents an analysis of the influence of axial displacement, as one of the technological parameters, on the wear of hob milling tools in the gear cutting of cylindrical gears with oblique teeth.

Tribological processes and failure of plain bearings significantly affect the availability, adaptability, reliability and productivity of modern technology, maintenance costs, energy costs and the costs of modern production. The research of tribological processes and failure of plain bearings should indicate the possible causes and the necessary measures to be applied in order to reduce the tribological processes and failure of plain bearings. In this paper, possible causes of tribological processes and failure of plain bearings were analyzed. Having in mind the most important causes of tribological processes and failure, a proposal for monitoring the condition is given.

Tribological Processes in the gear cutting of cylindrical gears on cutting elements of hob milling tools develop under specific conditions. The particular requirements under which the contacts between the hob milling tools and the workpiece material are made, make it difficult to become familiar with the tribological processes on them so that today there is more knowledge about their consequences on the machined surface of the teeth and the cutting elements of the hob milling tool, and less about their nature. In this paper, based on the experimental investigations, the wear analysis of three-treads uncoated and coated integral hob milling tools in the gear cutting of cylindrical gears is given.

Kinematic group of third class can not be described in a standard way. This kinematic group can be brought down to several general cases. Each case is specific. Their application is met in many complex mechanisms as part of mechatronics system. For kinematical analysis several numerical and graphical methods are used. In this paper the method of fixed point for kinematical description of third class type RR-RT-TR will be used. This method differs from all the rest used up to now and can be done numerically by using computer or graphically. The basic idea of this method is decomposing the kinematic group of third class to the kinematic groups of second class. Then the Banach's principle of contraction is used. It belongs to a class of theorems of fixed point. The method is very efficient and gives very quick and accurate solutions concerning the position of complex mechanisms as a part of the mechatronics system, well as the velocities and accelerations too.