Vibrodiagnostics of metal-cutting machines is an efficient method to increase reliability of all elements of the technological system «machine tool-device-instrument-detail». The development of vibrodiagnostic methods is especially important for milling metal-cutting machines which operate in intermittent cutting mode and are exposed to shock-vibration loads. One of the trends in the development of metal cutting equipment is to increase its productivity by expanding the ranges of cutting modes. Increase in the combination of cutting modes leads to increased probability of coincidence of the natural frequencies of the equipment and the frequencies of the cutting process which in its turn leads to operation of the machine equipment elements under resonance conditions. In the article we provide the results of our research aimed to develop the method to reduce shock-vibration load on tool and peak-factor equipment of milling machine. In our research we developed the technique that makes it possible to measure not only the general level of vibration, but also other parameters used for vibrodiagnostics, for example, the value of the peak factor has been developed. The method includes the development of a principle layout and of a plan for a three-factor experiment, construction and analysis of vibrational and spectral diagrams of the milling process for the assignment of optimal modes that provide machine operating at lower level of shock-vibration loads. Based on the results of the work we have come to the conclusion that it is rather promising to use the peak factor in analysis of the milling machines reliability.

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Abstract. The research aims to study the vibration isolation device using the elastic forces of the electromagnetic suspension. The optimum gain values of the signal feedback circuit, which minimize the impact of noise introduced by the elements of the active vibration isolation device, are determined. The possibility of developing the vibration isolation device with the control circuit coefficients found on the boundary of the stability region is considered. The paper provides the amplitude-frequency characteristics of a single-mass electromagnetic suspension.

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Results of experimental studies of pneumomechanical atomization process of slurry fuel with a plasticizer in an aerodynamic simulator of power boiler furnace are presented. Analysis of the current state in the field of research of slurry fuel atomization processes has been conducted. Influence of pressure of slurry fuel and air on the structure of the emerging spray cone have been analyzed. The values of characteristic dimensions of three zones of spray cone have been determined: core, middle and outer zones. Effect of pressure of the sprayed slurry fuel and air on the period of stable spray cone formation and geometric characteristics of the zones has been experimentally confirmed. Ranges of velocities and sizes of droplets in the flow at various pressures have been distinguished. The quantitative values of slurry fuel droplets with different velocities in the process of its pneumatic spraying have been obtained. It has been established that the largest number of particles in the study area have velocities up to 8 m/s; a significant number of droplets (up to 20%) have velocities from 8 to 32 m/s; velocities of 32 m/s and more are typical for 1% of droplets. During the results processing, aerosol particles with a size of 1 micron or less have not been taken into account. The values of We criterion for the respective sizes and velocities of the sprayed fuel droplets have been determined. It has been established that significant part of the droplets undergoes catastrophic crushing, which is characteristic for the values of We numbers from 7800 and higher. The obtained results can be used for mathematical and physical modeling of the process of slurry fuels atomization in the furnaces of power boilers in order to predict the aerodynamic characteristics of the designed and existing units.