High-Sensitivity and Low-Noise Interrogation for Spindle Fault Monitoring

To reduce the error, the stiffness of the high-precision machine tool spindle is often remarkably high, and the strain, when subjected to force, is extremely small. It is difficult for traditional strain monitoring methods to monitor the failure of the spindle. In this paper, enhanced sensitivity of the fiber Bragg grating (FBG) interrogation system is proposed, which can increase the sensitivity of traditional FBG strain sensors at high bandwidth (0–4 kHz). The system measurement sensitivity reached 96.9 mV/με, and the minimum strain reached 0.1 με. High-stiffness spindle misalignment faults and bearing outer ring faults can be identified.