DEFECT CHARACTERIZATION OF ROLLER BEARING SURFACES WITH LASER DOPPLER VIBROMETRY

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-mu-m. Velocity measurement provides a much higher bandwidth for defect detection. Cracks down to 22-mu-m in width can be detected with a 150-mu-m by 500-mu-m wide laser spot size. Cracks smaller than 22-mu-m 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.