OBRABOTKAMETALLOV Vol. 25 No. 1 2023 technology In accordance with the dimensional scheme of the internal grinding process, shown in Fig., the displacement balance equation takes the form: 1 i yi fi i i yi A S N t R r A ω - D = + = D - D + D + D , (1) where i A D – current changes in the value of the center-to-center distance, due to the radial feed of the grinding head, m; yi S – radial tool feed, m; N – preload, m; fi t D – changing the actual cutting depth, m; i R D – current tool wear, m; 1 i rω - D – the amount of material removed before the current revolution, m; yi A D – current change in elastic deformations. During internal grinding, an uneven removal of the allowance is observed, a waviness is formed on the surface of the workpiece [25, 26]. Based on this, it can be assumed that not only the removal of the allowance will change according to the harmonic law, but also other parameters included in the balance equation of displacements. For a visual demonstration of this phenomenon, the processing cycle by solving the displacement balance equation will be calculated [27, 28]. Initial data: the material of the workpiece is titanium alloy VT3, d = 150 mm, grinding head AW 60×25×13 63C F90 M 7 B A 35 m/s , circumferential speed of the wheel Vk = 35m/s, workpiece speed Vu = 0.25 m/s, radial feed Sui = 0.005 mm/r, number of grains per unit area ng = 15.86·106 pcs/m2, corner radius the grain vertex r g = 7.31·10 -6 m). Results and its discussion When calculating the parameters of the penetration stage, the values of the transverse feed Sy1 = 5·10 -6 m and preload N = 10×10-6 m are preset, according to the values, given in the reference literature [16]. Let’s perform the calculation of the first revolution: 1) Find the sum of the parameters of preload and cross feed: 6 6 6 1 1 5 10 10 10 15 10 y A S N - - - D = + = ⋅ + ⋅ = ⋅ , m 2) Determine the increment of elastic deformations in accordance with the equation: yi TS y A P D = ω ⋅ D , (2) Internal grinding process scheme
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