Visualization of Mechanical Microvibration and Machine Diagnosis

Factory machine diagnosis is important for preventive maintenance. Diagnosis equipment needs to be reliable and easy to handle, and the diagnostic results should be easily recognizable. An equipment that meets the above conditions is developed; it comprises a laser beam source, leaf spring with a mirror and a magnet as a position-adjustable mass, a copper plate, and a remote switch, if necessary. The principle is based on optical lever and mechanical vibration resonance. The laser spot vibration trajectory is irradiated onto the wall, ceiling, floor of a factory, or the housing of a machine as a screen. An equipment (29 mm $\times35$ mm $\times22$ mm) placed on the vibrating machine irradiates a laser beam and the magnified vibration is displayed on the screen. In this paper, the theoretical model and the equipment are presented, and the measured vibrations for a test vibrator and an actual machine are shown. A peak-to-peak vibration of 0.006 mm measured by a vibrometer is magnified to the 115 mm laser beam spot trajectory. The magnification is 38,333 times (91.6 dB), which is even larger on screens placed farther away. The calculation results by the theoretical model are in good agreement with the measurements.