A6.3 - Automated Non-Destructive Testing of Roller Bearings using GMR-Sensorarrays

Their small size together with a remarkable field sensitivity are the most prominent features of presentday GMR sensors paving the way for various applications in automated magnetic non-destructive testing (NDT). This work presents a prototype for fast and automated magnetic testing of roller bearings. A local magnetization unit excites the magnetic field inside the bearing. As a result of a design study and the following wafer fabrication the probe was equipped with NDT-adapted GMR sensor arrays, in which 48 elements measures the field response. The detection of 40 μm deep defects could be resolved with a SNR of better than 20 dB. We also report of first reconstruction results, in which the defect depth can be determined with relatively high accuracy.

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