Investigation of the Dynamic Behavior of Machine Tools During Cutting by Operational Modal Analysis

Abstract

A common approach for the experimentally estimation of modal parameters is the Experimental Modal Analysis (EMA). EMA takes place in the standstill of the machine, consequently neglecting effects that only occur during the cutting process. Alternatively the Operational Modal Analysis (OMA) makes possible to investigate structures under operational loads and conditions. In this paper, a machine tool is investigated during cutting and the modal parameters are estimated by OMA, with several identification methods working in the frequency domain as well as in the time domain. These results are also contrasted to EMA to investigate the differences between cutting and standstill.

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“…Here, existing approaches from experimental modal analysis, e.g., impact testing via an impact hammer, can be used. A third alternative is the operational modal analysis [20][21][22]. The transfer functions H TT and H ET can be obtained by excitation at the TCP, e.g., via an impact hammer, and measuring the response with an accelerometer at the TCP and at the linear encoder, respectively.…”

“…Dependent on the machine tool concept the dynamic behavior at the TCP depends on the position of the feed axes. Some examples for regular transfer function can be found in [20,21,24,25]. For the feed drive closest to the TCP the approach in Equation ( 6) mainly eliminates position-dependent behavior of the TMFs.…”