Oborskyy G. Scientific principles of precision processing technological systems’ parametrical reliability and dynamic quality maintenance

The thesis is devoted to the problematics in reliability of precision processing as to modeling and maintenance on parameter « dynamic stability ». The questions of mutual influence between fast-running processes (vibrations) both processes of average speed (deterioration of the tool and thermal factor withing cutting area) are considered, that allowed to develop scientific prinicples of maintenance of dynamic stability as to precision processing (ex. g.: finishing-cutting machine-tools) as well as to develop time-dependently the dynamic parameter. The initial calculative model for definition of stability resource as to precision machine tools has been developed with respect to the influence of fluctuations’ level at a single course on casual fluctuations of boring bar with a cutter while cutting process. For the first time the dynamic model of machine-tools system includes the temperature factor and dynamic component of deterioration of the tool, that allowed determining both proving the presenceof optimum temperatures (speeds of cutting), which provide the best stability(resistance) of the tool. In view of influence of random factors the possibility to obtain at the issue of calculations the values of a level of parametrical reliability of the engineering systems. The principles of optimal selection of designer and technological parameters of the engineering systems ensuring a given level of reliability on parameter « dynamic stability » are developed. In particular, the problems of selecting the optimum modesfor thin-boring has been resolved. Also there are proved the basic constructive elements spindle units (gap distance between supports are designed; the optimum size of preliminary tighting whilst duplexing as well as the distance between duplexed bearings), the methods of optimum adjustment of fluctuations equalisers allowing to ensure the stable dynamic quality of elastic system of the machine tool are developed.