Eddy current testing (ET)

Eddy current is the method of choice for all conductive materials, especially when it comes to detecting surface or near-surface cracks as well as defects located under multiple layers or non-conductive coatings.

Electrical conductivity is the prerequisite for testing with eddy current. Even poorly conductive materials such as titanium or nickel-based materials can be tested without problems.

An electric current is passed through a probe. The resulting magnetic field enters the surface to be tested and generates a so-called eddy current. This in turn acts against the generating current through its own magnetic field. If the probe now encounters a defect, its eddy current changes and, of course, so does its magnetic field. The difference between the two magnetic fields is displayed in the eddy current device.

Expertise is particularly required when setting up the device, since comparison patterns are necessary. Zeppelin has years of know-how in designing the introduced defects in such a way that they are comparable to natural defects and lead to a meaningful result.

Manual eddy current testing is an important test, especially for repair. Components can also be tested with a protective coating, eliminating the need for time-consuming paint stripping.

Eddy current has become particularly popular in the aerospace industry for testing aircraft structures that are already in service. But eddy current testing is also increasingly used in industry for finding cracks, delaminations, mix-up tests or even for coating thickness measurements.