OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 5 No. 2 2023 cal feed movements perpendicular to the profile of the part and shifts with each cycle along the part profile at a given discrete value depending on the required machining accuracy. An example of such parts is spur coarse pitch gears with pitch values greater than 9 mm and a face width greater than 50 mm, for which the machining according to the first method is effortful. The machining of parts by the touch method with a continuous tool feed movement along the profile of the part has become widespread; there is a large number of works devoted to this problem [1–6]. The issues of machining by the touch method with discrete feed movement along the profile of the part due to the lower prevalence of shaped parts with heavy thickness are less studied [7–10]. The main disadvantage of this method is lower machining speed, which is due to the presence of discrete tool movement between the cycles of reciprocal movements. Moreover, the value of discrete tool movement ΔΩ for a set machining accuracy depends on the value of the surface curvature being formed (fig. 2), which leads to a lower machining speed. To increase the machining speed in this case, it is advisable to use milling cutters having a concave shape of the generating surface, which ensures its tighter fit to the surface to be machined. The generating surface is the one formed by the shape-generating cutting edge of the milling cutter due to its primary motion, i.e. the motion that determines the cutting speed [11]. However, with regard to the designs of prefabricated side milling or face milling cutters equipped with replaceable polyhedral inserts (RPI), it can be said that there are no RPIs of a standard design with a concave cutting edge. In [12–16], it has been found that when a milling cutter with a linear RPI cutting edge a b Fig. 1. The formation of the surface of the part by the touch method with the feed movement of the tool: a – continuous; b – discrete a b Fig. 2. The dependence of the value of the discrete tool movement on the curvature of the profile of the surface being processed: a – at low curvature; b – at high curvature
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