OBRABOTKAMETALLOV Vol. 25 No. 4 2023 technology a b Fig. 4. Microstructure of the specimens: the area near the edge of the specimen (a); the central part of the specimen (b) Study of cutting forces when machining the specimens At the third stage of our work, we conducted a study of the cutting forces arising during milling of the printed specimens. When processing the printed specimens, the greatest attention in this work was paid to the component forces Ph and Pv (fig. 5, 6). This is because the Px force is small relative to other forces. It is directed along the axis of the cutter. This is the direction of the highest rigidity of the cutter (fig. 6). The radial direction is the direction of the lowest rigidity used for the end mill. Based on this, the force Py acting radially on the cutter axis leads to vibration. During the study, we constructed graphs of changes occurring in the cutting forces during milling with a four-flute cutter for up and down milling processes. Up milling process When up milling with a four-tooth cutter having a diameter of 8 mm at t = 3.8 mm, the change in the components of the cutting forces as a function of time τ (s) is shown in fig. 7. The cutter diameter that is slightly less than 4 mm was taken to ensure that the next tooth had not yet started cutting. The graph shows the forces generated during one full revolution of the cutter. The curves of the main cutting force components Ph and Pv show four clear peaks. These peaks correspond to the work of each of the four cutter teeth. The force increases when the tooth cuts into the workpiece and the force decreases when the tooth leaves the cutting zone. a b Fig. 5. The direction scheme of the components of the cutting force in asymmetric up end milling with a four-tooth end mill with a diameter of d = 8 mm at a milling depth of t = d/2 – 0.2 mm = 3.8 mm: when tooth No.1 enters the workpiece (the previous tooth No.4 is already out of contact) (a); when tooth No.1 leaves contact with the workpiece (the next tooth No.2 has not yet come into contact with the workpiece) (b)
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