Actual Problems in Machine Building. Vol. 12. N 3-4. 2025 Innovative Technologies in Mechanical Engineering ____________________________________________________________________ 44 MODEL OF HEAT TRANSFER BETWEEN A SINGLE DIAMOND GRAIN AND THE CUTTING SURFACE DURING GRINDING Poltavets V.V., D.Sc. (Engineering), Associate Professor, e-mail: poltavetsvv@gmail.com Donetsk National Technical University, 58 Artema st., Donetsk, 283001, Russian Federation Abstract Grinding difficult-to-machine materials with diamond wheels is accompanied by high temperatures generated at the contact surfaces of the diamond grains. Heating of the diamond in contact with an oxygen-containing medium leads to its oxidation, while contact with iron (or ironbased alloys) leads to graphitization. This paper addresses the problem of determining the temperature at a single diamond grain at its point of contact with the cutting surface. The solution of the problem is based on a simplified model of heat transfer between a single diamond grain and the workpiece being machined. This solution is based on two assumptions. First, it is assumed that the mechanical energy of cutting by a single diamond grain is completely converted into thermal energy. Second, diamond grains of the most probable size are represented as cylinders with a height equal to the base diameter. The calculated temperature values obtained by the proposed method make it possible to determine the average force on a single diamond grain at which diamond oxidation will be absent, as well as the corresponding values of the cutting force components on the grinding wheel. These values act as technical constraints when selecting machining operation mode. Keywords Grinding, diamond wheel, single grain, diamond oxidation, graphitization, heat transfer, contact area, thermal conductivity, thermal diffusivity.
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