Information properties of frequency characteristics of dynamic cutting systems in the diagnosis of tool wear

OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 6 No. 3 2024 It is important to note the properties of VAE: – the expected value of the distances between pulses determines the burst frequency; – the dispersion of the spacing distances causes a broadening of the spectral line (fig. 6); – wear development causes an increase in contact interaction acts and increases the uncertainty of the pulses. Therefore, the development of wear causes a shift of the burst frequency and a broadening of its spectrum; – the signal amplitude also indicates the development of wear. As wear increases, especially when approaching its critical value, a low-frequency amplitude modulation of the VAE is observed. Fig. 7 shows examples of sequence-to-spectrum Sf,f(ω) conversion. The broadening of the spectral line with increasing σf is noticeable. Its mappings in the VAE are also similar. The experimentally measured and given spectra in Fig. 7 qualitatively coincide, but its quantitative estimates vary depending on the technological regimes. The main frequencies of VAE shift to the high-frequency region as the cutting speed increases. This is due to the fact that the distances between pulses are mainly path dependent. It also depends on the current cutting area, and variations in depth and feed rate practically do not change its frequency а b c d Fig. 6. Model of force emission as a random pulse sequence: а – fragments of high-speed filming of the formation of chip elements; b – diagram of the formation of fragments of power impulses; c – random force sequence model; d – example of spectral decomposition of a random sequence

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