Research into the wear of wheels during electroerosive diamond grinding with variable polarity of the electrodes in the cutting area

Abstract

The electro-erosive wheel dressing exerts a significant impact on the machining accuracy of
a piece and the efficiency of the profile grinding process. To effectively control machining
accuracy, the most important is the error due to the wear of a diamond wheel. The wheel should be
dressed when wear approaches to the border but does not go beyond the tolerance field. This would
reduce the number of defects at machining and bring down the utilization of diamonds. In addition,
this reduces the dressing time and, therefore, improves the efficiency of profile diamond grinding.
The paper reports the methodology and results of an experimental study into the wear of
profiled diamond wheels. The specific utilization of diamonds was examined on the grinding
wheels of the direct profile. The amount of a wheel linear wear was measured by a contactless
method applying a special device based on the use of eddy current sensors. This was followed by
determining the integrated amount of the worn volume of a diamond layer; after that, the weight of
the used diamonds was measured. The mass of the sanded material was determined by weighing it
before and after machining.
A mathematical method of planning and analysing experiments was used to establish the
functional dependence of the specific utilization of diamonds on the technological machining modes and the diamond layer parameters. The result of a regression analysis is the derived functional
dependence of diamond specific utilization on the following factors: the concentration of diamonds
in a wheel, the grit of the tool, the grinding wheel velocity, the depth of grinding, and the speed of a
piece.
To determine the patterns of the wear of the shaped diamond wheel, we received an imprint
of its profile on a control plate made from a solid alloy and measured the coordinates of the points
of the working part of the profile relative to the non-utilized areas. Determining the difference of
coordinates before and after the experiment has helped find the amount of the radial wear of the
grinding wheel at the appropriate profile point.