Analysis of cutting force in electrical discharge grinding with change polarity of electrodes

Abstract

A methodology for calculating the components of the cutting force during electroerosion
grinding with variable electrode polarity is proposed, which helps to choose the optimal
processing modes for one installation of the surfaces of machine parts. An example of calculating
the components of the cutting force during flat mortise grinding using this method is given. In this
case, the normal component of the cutting force is calculated not only on the end face, but also on
the periphery of the circle, taking into account the influence of cutting and deforming edges. An
analysis of the existing mathematical dependencies for determining the cutting force during flat
diamond mortise grinding was carried out. The value of the cutting force acting during grinding is the most important characteristic of the processing process. It depends on the working conditions
of the machine, the tool and the level of accuracy of the obtained part. The developed
methodology for determining cutting force components during grinding takes into account the
effects of both cutting and deformable grains. Consequently, the total normal and tangential
cutting force components act along the contact line, both at the periphery and the end of the
grinding wheel. The thickness of the sheared layer is calculated on the condition that the volumes
of the supplied and sheared material are equal, taking into account the flexibility of the system
and the intermittentness of electric discharges due to changing the polarity of the electrodes.
Based on the developed methodology, the components of the cutting force were calculated during
electroerosion grinding with variable electrode polarity. Rough grinding was performed with the
end face of the wheel, semi-clean – with a transitional radius edge, and fine grinding and
calibration – with an unloaded area of the wheel’s periphery, which ensures its high stability. The
normal component of the cutting force, which has a maximum value at the end of the circle,
practically does not affect the accuracy of forming the part, since it is located parallel to its axis.
This technique can be used for various types of grinding, as well as for the study of thermal stress
of the process, optimization and productivity of mechanical processing.