What is the significance of lift-off in Eddy Current Testing?

In Eddy Current Testing, lift-off refers to the distance between the probe and the test surface, which significantly affects the eddy current response. This distance is crucial because it determines the depth of penetration of the eddy currents into the material being tested. As the lift-off increases, the eddy current strength decreases, leading to a reduced response signal. This relationship is important for accurately interpreting the test results, as variations in lift-off can indicate changes in material properties, surface conditions, or the presence of flaws.

The concept of lift-off is central to the effectiveness of Eddy Current Testing, as it helps technicians calibrate their equipment and understand how distance influences the testing outcome. Effective management of lift-off ensures reliable detection and characterization of defects or material properties, contributing to the overall precision of the testing process.