NC Machine Tools Fault Diagnosis Based on Kernel PCA and -Nearest Neighbor Using Vibration Signals

Figure 5

Time-frequency domain waveform sample of normal and single tool wear classes.

(a) Time-domain waveform with all tools normal

(b) Frequency-domain waveform with all tools normal

(c) Time-domain waveform with single tool wear

(d) Frequency-domain waveform with single tool wear