Analytical study of grinding forces with the imposition of ultrasonic vibrations with high amplitude

An analytical study of the grinding forces under the superposition of ultrasonic vibrations (UV) with an amplitude providing intermittent contact of the abrasive grains of the circle with the workpiece, was performed. The grinding force was defined as the sum of the forces from the individual grains of the circle located on different sections of their trajectory relative to the treated surface of the workpiece. When the grain is moved in the contact zone of the circle with the workpiece, its operating mode changes and depends on the phase of vibrations. Moving relative to the workpiece, the grain performs plastic deformation and micro-cutting, on part of the trajectory it can come out of contact with the workpiece. The sequence of implementation of these modes depends on the phase of the UV. The components of the grinding force were calculated as the arithmetic mean of their values determined at different vibration phases. The coordinates of the points on the grain movement trajectory corresponding to the change in its operating mode were determined numerically. Numerical simulation of forces using the obtained dependences and experimental study were performed for flat grinding of 12H18N10T steel blanks by the periphery of the circle. The frequency of the superimposed UV is 18.6 kHz; the amplitude of the oscillations in the direction coinciding with the axis of the grinding wheel is 10 microns. To impose vibrations on the workpiece in the course of experimental studies, a device was used in which the workpiece is one of the links of the vibration system. It is established that the difference between the calculated and experimental values of the components of the grinding force is 8 ... 15%. With the imposition of a UV, grinding force is lower by 20 ... 21% than without their use.