Actual Problems in Machine Building. Vol. 10. N 1-2. 2023 Innovative Technologies in Mechanical Engineering ____________________________________________________________________ 10 electric current (later on, the method of electrical modelling was significantly developed by A.N. Reznikov). Simultaneously with Chao and Trigger, a large group of American researchers were engaged in the analytical study of temperatures. Each of them solved a specific problem, which made it possible to determine the temperature at a certain point or on a surface that is directly related to the cutting zone. So, E. Loewen and M. Shaw, based on the method developed by J. Jaeger, presented the solution to problems about temperatures in the shear plane and on the front surface of the cutter. D. Weiner derived formulas for calculating the amount of heat entering the workpiece. F. Ling and E. Seybel in 1955 theoretically determined the relationship between friction and temperature at the contact surface of the chip with the cutter. At the same time, domestic scientists theoretically investigated the direction and intensity of heat flows during cutting, temperatures on the contact surfaces and temperature fields in the tool and workpiece, and the mechanism of action of the cutting fluid. In 1952 B.Ya. Borisov, using the method of point sources, tried to calculate the temperature of the cutter at the place where the chips came off the front surface and investigate its temperature field. In 1954 P.I. Bobrik, using the Rykalin method, obtained a formula for calculating the temperature at a separate point of the chip. In 1956 N.V. Talantov, using the method of imposing instantaneous heat sources, obtained a formula for calculating the cutting temperature as a sum, taking into account the temperature from the heat released as a result of plastic deformation and the temperature from the heat released during the friction of the chips on the front surface of the cutter. The most comprehensive and in-depth studies of thermal physics of cutting were carried out by A.N. Reznikov, who worked in Kuibyshev Polytechnic Institute, and then (since 1967) in Togliatti Polytechnic Institute. From the beginning of the 1950s A.N. Reznikov developed and supplemented the theory of fast-moving heat sources developed by Rykalin as applied to welding processes and by Eger as applied to the friction process. In 1958 A.N. Reznikov published [9-10] the results of a three-year-old study of the temperature field in the chip, which arises under the action of the friction force on the front surface of the cutter. The theoretical formula (3) for determining the temperature at the point of the chip with coordinates x, y had the form: , (3) where λ and α are the coefficients of heat and thermal diffusivity; k is chip shrinkage; ν is the cutting speed; σо is the specific friction force at the cutting edge; lc is the length of contact between the chip and the cutter; τ is a function that depends on temperature fields for instantaneous point sources during turning, milling, drilling and abrasive processing, which was obtained by A.N. Reznikov. He believed that the temperature field from the action of a heat source of any form, the duration of action and the speed of movement can be obtained as a result of the superposition of temperature fields that arise under the action. A.N. Reznikov considered the cutter as an endless wedge, the chips as an endless rod, and the part as a half-space. In the system of these bodies, there were heat sources from deformation in the shear plane qd, from friction at the contact area of the chip with the cutter qmn and from friction at the contact area of the tool with the product qm3, as well as heat sinks, reflecting the heat exchange between the cutter and the chip qn and product q3, (Fig. 3). A.N. Reznikov adopted a combined (uniform power law) distribution of tangential stresses along the length lc of the contact pad of the chip with a cutter, as a result of which the calculated temperature reached a maximum at a distance of (0.35 ... 0.55) lc from the tip of the cutter. Thus, the temperature maximum was in the zone of wear dimple formation on the front surface.
RkJQdWJsaXNoZXIy MTk0ODM1