OBRABOTKAMETALLOV Vol. 26 No. 2 2024 technology It should be noted that the force Pv is directed away from the operator, i.e. in the opposite direction of the OY axis, i.e. the milling cutter tooth pushes the workpiece away from the operator, because when measured, it is displayed on the dynamometer monitor with a minus sign (–). In Fig. 12, the force Pv is indicated on the positive axis so as not to draw another axis. Despite the negative magnitude of the forces Pv and Px, its absolute value is taken into account – the greater it is, the greater the force. The sign of the force Ph is positive, i.e. the direction of the force coincides with the direction of the OX axis (see Fig. 9). The sign of the force Px is negative (–), this indicates that it is directed in the opposite direction from the direction of the OZ axis, i.e. the milling cutter tooth pulls the workpiece up (see Fig. 9) due to the positive angle of inclination of the screw groove ω (see Table 4). Direct proportionality of graphs Phmax = f(fmin), Pvmax = f(fmin) from the value of the feed per minute fmin (see Fig. 12) allows for t = 1 mm and the specified other cutting modes to use equations described by a linear relationship: Phmax across = 266.4+0.556∙fmin; (1) Phmax along = 200 + 0.545∙fmin; (2) Pvmax across = 100.4 + 0.899∙fmin; (3) Pvmax along = 46.2+0.135∙fmin. (4) Direct proportionality of graphs Pxmax = f(fmin) depending on the value of the feed per minute (see Fig. 13) allows for t = 1 mm and the specified other cutting modes to use the equations: Pxmax across = 10.8+ 0.162∙fmin; (5) Pxmax along = 3.97+0.128∙fmin. (6) In all the considered cases, the magnitude of the forces Phmax, Pvmax and Pxmax in the feed direction along the feed direction during the synthesis of specimens (workpieces) is slightly less than in the perpendicular feed direction (see Fig. 12 and 13). The analysis of Fig. 14 shows, despite the fact that at a cutting depth of t = 1 mm, a four-teeth milling cutter should have contact with the specimen of only one tooth and therefore the forces should decrease to zero, but this does not happen. This is most clearly seen in the graphs of changes in the feed force Ph (blue color of the graph). As the feed increases, the minimum Ph value increases. In all cases, four peaks and troughs (valleys) are clearly visible, which indicates the operation of four teeth. The different magnitude of these peaks indicates the presence of a small radial runout of the teeth. For the milling cutter used, any two adjacent teeth have the same distance from the axis of rotation of the milling cutter, as indicated by the same magnitude of the greatest Ph force. This indicates that there is a slightly different distance of the cutting edge of the teeth relative to the axis of rotation of the spindle, and not the displacement of the axis of the cutter when it is fixed in the collet chuck. I.e., the observed error appeared during the manufacture of the milling cutter, and not when it is installed in the chuck. The steepness of the rise and fall of the force Ph graph, as the most characteristic, clearly visible and important, is approximately the same (see Fig. 12, 13), although it was expected that the decrease should occur more quickly, because during conventional milling, the tooth exit has a very short exit period (the uncut chip thickness ai decreases more quickly before the tooth completely leaves contact with the specimen) compared to the period of increasing the uncut chip thickness. We explain this phenomenon by changing the direction of the force Pz as the main force when removing the allowance. Before the tooth leaves the contact, the force Pz rotates along the rotation of the cutter and increases the force Pv to a greater extent, rather than the Ph (see Fig. 12). Therefore, the decrease in the
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