| Abstract: | Laser Doppler vibrometry is presented as an effective method of surface profile measurement and surface crack detection in rolling bearing balls. For both inspections, a surface velocity profile is used in addition to surface displacement profile. An experimental setup and a signal-processing algorithm are used to obtain digitized surface profiles and power spectral density measurements of ball surfaces. Profile measurements are presented that match lobed ball frequency results with a resolution of 0.025 μm. Velocity measurement provides a much higher bandwidth for defect detection. Cracks down to 22 μm in width can be detected with a 150 μm by 500 μm wide laser spot size. Cracks smaller than 22 μm can be detected by decreasing the laser spot size. The method is well suited for a manufacturing environment because of its durability, simplicity, and high speed. |
