Patent ID: 8436608
Filing Date: 2013-05-07
Classification: G01N

Abstract:
1. A multi-frequency eddy current (MFEC) inspection system for inspection of case hardening depth on a part, the MFEC inspection system comprising: a generator configured to generate one or more multi-frequency excitation signals, wherein the generator comprises a function generator; an eddy current probe configured to be disposed at one side of the part and comprising one or more drivers and one or more pickup sensors, wherein the one or more drivers are configured to receive the one or more multi-frequency excitation signals to induce eddy currents in the part and the one or more pickup sensors are configured to detect the induced eddy currents within a local area of the part to generate one or more multi-frequency response signals; and a processor configured to receive the one or more multi-frequency response signals for processing to determine a case hardening depth of the local area of the part, wherein the processor comprises a lock-in amplifier, and wherein the function generator is further configured to supply one or more reference signals with the same frequencies as the respective one or more multi-frequency response signals to the lock-in amplifier.