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THE PROBLEM OF MODELING A LEADING CRACK DURING VIBRATORY TURNING

The work objective is to consider the possibility of creating conditions for appearing a leading crack by adjusting the modes of vibratory turning, regardless of the properties of the machined materials. 
The problem to which the paper is devoted. The paper is devoted to modeling vibration turning for developing stresses in the machined material to create conditions for appearing and maintaining a leading crack and in the cutting area during vibratory turning, the search for optimal modes to create conditions for its existence. 
Research methods. Modeling was carried out by the finite element method in Deform software application. The starting point for modeling was the results of field experiments on vibratory turning of corrosion-resistant austenitic steel 12X18H10T. 
The novelty of the work lies in the application of the finite element method to define the modes of vibratory turning in order to create a certain area of internal stresses in the processed material in a given direction for forming a leading crack. 
Study results. As a result of modeling, optimal turning modes are defined during vibration cutting, which will create conditions for appearing a leading crack and exhausting the plasticity margin of the machined material. 
Conclusions: The creation of a leading crack and the exhaustion of the plasticity margin of the machined material contributes to the chip control, the formation of microgeometry of the machined surface during vibratory turning, the reduction of cutting forces when turning hard-to-machine materials and built-up surfaces.