Lift-off in eddy current testing is utilized for measuring what?

Lift-off in eddy current testing refers to the distance between the probe and the conductive material being inspected. This concept is crucial when measuring the thickness of non-conductive coatings that are situated over conductive substrates. When a probe is applied to inspect a coated part, variations in lift-off will influence the eddy current response.

By measuring the impedance changes of the coil when lift-off occurs, technicians can distinguish between the conductive substrate and the non-conductive coating. This capability allows for accurate assessments of coating thickness since the lift-off effect alters the coil's signal depending on how far it is from the material surface. By evaluating these changes, one can effectively quantify the thickness of the non-conductive coatings, making it a vital parameter in quality control and material inspection processes.