Research on a fault monitoring system in free-form surface CNC machining based on wavelet analysis

In carrying out experiments on tool breakage and undercut of a workpiece of free-form surface using wavelet analysis, both of the fault features can be extracted in a special frequency segment of wavelet decomposition. According to the feature of transient fault, the authors proposes for the first time an automatic determination technology of the threshold by the use of the adaptive filter characteristics of wavelet transformation. Based on profound research on steady fault features, this paper makes an effective token of steady fault feature by using the wavelet energy method, and proposes the new idea to identify the cut-in and cut-out cases, thereby successfully giving a unique description quantitatively of the characterization of the variation of fault and cutting conditions in the monitoring system.