OBRABOTKAMETALLOV technology Vol. 25 No. 1 2023 a b Fig. 3. Pattern of the passage of the cutting edges through the processing zone: a – the trajectory of the ith tooth corresponding to the effective diameter of the tool; b – deviation trajectory of the front spindle support (Formulated by the authors) Ta b l e 1 Roughness parameters after machining with a ball–end tool Number of teeth Angle of inclination, ° Roughness parameters, μm Ra Rq Rz Rt Rp 1 10 0.436 0.543 2.143 4.094 1.490 25 0.498 0.531 2.532 4.810 1.355 40 0.401 0.502 2.512 4.800 1.271 2 10 0.661 0.824 3.048 4.536 2.001 25 0.620 0.793 5.104 7.599 3.079 40 0.373 0.465 2.391 3.559 1.383 In this study, the output parameter is roughness, and to ensure the required surface roughness, along with the establishment of processing modes, an assessment is made of the dynamics of spatial oscillations of the front spindle support (see Fig. 3, b). At the same time, the amplitude parameters of roughness after processing with inclined ball-end tools with a different number of teeth during climb milling are presented in Table 1. When machining with a single-edge cutting tool, a change in the angle of inclination practically does not affect the change in the amplitude parameters of roughness, i.e. for the case under consideration, the range of the DS stability margin is maximum. The use of a double-edge cutting tool leads to significant changes in the output parameters, the discrepancies presented are often caused by the deviation and wear of the tool, resulting in a change in the active cutting zone and an increase in the level of vibrations [6] (Fig. 4). Analysis of the Table 1 as well as Fig. 4 allows drawing the following conclusions: 1) the greater the vibration displacement amplitude, corresponding to the cutting frequency, the higher the value of the roughness amplitude parameters; 2) the amplitude of vibration displacements does not change linearly with an increase in the angle of inclination, and a decrease in the quality of the machined surface occurs due to elastic deformations of the cutting tool, which is explained by the distribution of the cutting force components along the cutting edge [20, 23]. For the practical implementation of the principles of acoustic diagnostics, the information received on the current state of the processing process is required to be understandable and reliable. Fig. 5 shows the acoustic signal obtained during the experiment.
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