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Chatter vibrations are a major limitation for rough milling operations,leading to productivity reduction,low tool life and poor surface finish.It has been shown recently that the machine tool′s own drives can be used to increase the stability limit related to structural modes of the machine.To damp the low frequency modes,a new feedback loop is added to the classical position,velocity and current cascaded control.The objective of this study is to analyse the limitations of this new chatter suppression technique.Constraints related to the non-collocated control are first studied on a simplified three-mass model and then experimentally demonstrated on a three-axis horizontal milling centre.The industrial integration of the new control loop with sampling time constraints and limited drive′s bandwidth is analysed.After determining the appropriate conditions to use this chatter suppression technique,a cutting test demonstrates that the stability limit can be doubled in the low regions of the stability lobes.
Chatter vibrations are a major limitation for rough milling operations, leading to productivity reduction, low tool life and poor surface finish. It has been been seen that the machine tool’s own drives can be used to increase the stability limit related to structural modes of the machine.To damp the low frequency modes, a new feedback loop is added to the classical position, velocity and current cascaded control. Objective of this study is to analyze the limitations of this new chatter suppression technique. Constraints related to the non- collocated control are first studied on a simplified three-mass model and then experimentally demonstrated on a three-axis horizontal milling center. The industrial integration of the new control loop with sampling time constraints and limited drive’s bandwidth is analysed. After determining the appropriate conditions to use this chatter suppression technique, a cutting test demonstrates that the stability limit can be doubled in the low regions o f the stability lobes.