Surface formation under the conditions of electroerosion grinding with variable polarity of electrodes

Abstract

The contact zone is the area of mutual penetration of the cutting edges into the processed
material and the protrusions of the materials in the gaps between the grains. The parameters of the
state of the zone include its size and shape, the ratio of cut and uncut parts of metal in each area of
the zone, the physical processes of formation, including: chipping, heat generation, plastic
deformation of the material, tool material wear and damage, physical and chemical effects on
cooling lubricants.
The formation of the processed surface in the conditions of electroerosive diamond grinding
with variable polarity of electrodes in the cutting zone is investigated in the article. A physical
model of diamond tool wear has been developed considering the erosion processes affecting the
wheel connection. The construction takes into account dimensional wear, processes of chipping and
pulling out single abrasive grains from the bond, under the action of the components of cutting
forces, considering the probability of grain contact with metal, the size of wear sites and the actual
depth of microcutting.
The obtained ratios allow us to directly determine the probability of contact of the cut chips
from the body, formed by the cutting edge of the grain, with the bond surface of the grinding wheel.
When solving the problem of the probability of contacting the set of chips formed by the set of
edges of the grains lying in the working layer of the tool, it is also necessary to use the probability
of the density distribution along the depth.
The type of the obtained ratios directly shows that a significant part of the chips formed by
the cutting edges in contact with the rough surface of the workpiece are short and do not come into
contact with the ligament until separation from the body of the workpiece, even without shrinkage.
The obtained relations can be used in solving the corresponding problems of grinding the
periphery of the circle, for example, round external grinding. With a clearer description of the
process, it is necessary to directly apply the nonstationary representation, taking into account
additional nonstationary ones, introduced by the trajectories of the cutting edges as a function of the
angle of rotation of the circle and the part in the process of their interaction.