Eddy Current Inspection
Talon Test Labs offers expertise in automated Eddy Current inspection using rectilinear and turntable scanning with advanced data acquisition and analysis. In addition, TTL has the most advanced aircraft wheel inspection system available. These automated systems provide us with the ability to perform detailed digital evaluation of acquired data
Eddy Current Inspection Methods
Advantages of Eddy Current Inspection
- Detects surface and near surface defects
- Test probe does not need to contact the part
- Method can be used for more than flaw detection
- Minimum part preparation is required
The eddy current system allows us to acquire data similar to an ultrasonic scan for evaluation. Our unique Eddy Current software allows us to evaluate the signal in multiple views and to accurately locate indication position.
A different coil display can be generated from data acquired with a single absolute coil. The system is also able to display the results from a hand held bolt hole scanner.
Electromagnetic testing is a general test category that includes Eddy Current testing, Alternating Current Field Measurement (ACFM) and Remote Field testing. While magnetic particle testing is also an electromagnetic test, due to its widespread use it is considered a stand-alone test method rather as than an electromagnetic testing technique.
All of these techniques use the induction of an electric current or magnetic field into a conductive part, then the resulting effects are recorded and evaluated.
Eddy Current Testing uses the fact that when an alternating current coil induces an electromagnetic field into a conductive test piece, a small current is created around the magnetic flux field; much like a magnetic field is generated around an electric current.
The flow pattern of this secondary current, called an ''eddy'' current, will be affected when it encounters a discontinuity in the test piece, and the change in the eddy current density can be detected and used to characterize the discontinuity causing that change.
By varying the type of coil, this test method can be applied to flat surfaces or tubular products. This technique works best on smooth surfaces and has limited penetration, usually less than 1/4''. Encircling coils are used to test tubular and bar-shaped products.
The tube or bar can be fed through the coil at a relatively high speed, allowing the full cross-section of the test object to be interrogated. However, due to the direction of the flux lines, circumferentially oriented discontinuities may not be detected with this application.
Eddy Current testing utilizes principles of electromagnetic induction to locate near-surface cracks, measure thickness, and categorize certain material properties in metals. An eddy current probe generates a magnetic field that induces currents that flow in a circular path in the test material.
Changes in the integrity or thickness of the test piece will in turn affect current flow, the magnetic field, and ultimately the magnitude and phase of the voltage in the coil. The instrument monitors the probe output and displays information for analysis. Eddy current array systems use multiple probes to expand coverage areas and provide imaging capability.