OBRABOTKAMETALLOV technology Vol. 25 No. 4 2023 Σ σµ = = η 3 T ZT K A P L BL L, (37) = = ∑ 1 J ZT ZTj j P P , (38) where PZT is the tangential component of the force of cutting with the wheel arising from friction, N; η is the degree of recession of the circle [30]. σµ = η 3 ZT K P BL , (39) = , K z i L DS , (40) where LK is the length of the contact arc for flat grinding, m; D is the diameter of the grinding wheel, m. Then, the tangential component of the cutting force can be calculated as: σe σµη = + , , 3 table z i Z z i k V BS B P DS V . (41) We similarly obtain an expression for the radial component of the cutting force: σe ση = β + , , tg 3 table z i Y z i k V BS B P DS V . (42) In previous studies [30], we proved that tgβ ≈ 0.68 and ε ≈ 2.8. Let us take into account the obtained values in formulas (41) and (42) to obtain: σ σµη = + , , 2,8 3 table z i Z z i k V BS B P DS V , (43) σ η σ = + , , 1, 9 3 table z i Y z i k V BS B P DS V . (44) The adequacy of the above model of the cutting force of flat grinding was experimentally investigated in a university laboratory on a 3L722A flat grinding machine using equipment from KISTLER to record and analyze cutting forces. We measured the radial component of the cutting force as the most significant indicator for processing accuracy (fig. 4). A 3L722A flat grinding machine uses the wheel periphery for machining on a rectangular table, which corresponds to the considered flat grinding type. The technical capacity of the used KISTLER 9257B dynamometer meets the test requirements, while its accuracy is ± 3.5 %, which is sufficient for the measurements. Experimental verification was carried out on 500×20×20 mm (length×width×height) steel 45 (0.45 % C) samples. A sensor receiving signals from two modules was used to measure the cutting force. The received digital signals are then processed on a computer. A wheel with the most common characteristic 25AF40L10V was used. It should be noted that the developed force model makes it possible to take into account circles of various characteristics. Fig. 4 presents the experimental results in graphs reflecting the relationship of the radial component of the cutting force with changes in various parameters of the cutting conditions. The difference between the calculated values and experimental data averaged 10 %. Thus, the adequacy of the presented model for calculating the cutting force for flat grinding is proved.
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