On the Applicability of Modal and Response Representations in the Dynamic Analysis of Machine Tool Spindle Bearing Systems

The study reinforces the generally held view that the stability of the cutting process in single-point cutting operations is dominated by the response characteristics of a single mode of the spindle-bearing systems. The common practice of evaluating frequency response functions at the cutting zone achieves the objective of ascertaining the machine's chatter stability. It does not, however, give any indication of the effect of resonance of higher modes on the long-term performance consistency. The results of the study suggest that this can be assessed by examination of the modal characteristics of higher frequency modes which have significant responses at the location of the bearings. The analysis is illustrated by consideration of two typical machine tool spindle-bearing systems.