Comparative evaluation of coil and hall probes in hole detection and thickness measurement on aluminum plates using eddy current testing

Abstract

The design, test, and comparison of one coil probe and one Hall probe using eddy current testing in the field of nondestructive evaluation is presented. Real tests were performed using alumi� num plates. This research concludes that (1) both probes provided broadband frequency responses up to 1000 KHz, which are wide enough for the most common applications; (2) the coil probe provided higher signal to noise ratio (SNR) than the Hall probe; (3) both probes detected the four holes success� fully and provided enough sensitivity to classify them by diameter; and (4) the coil probe provided higher accuracy than the Hall probe when measuring thickness lower than 1 mm, and lower accuracy when measuring thickness higher than 1.5 mm.