System and method for using eddy current edge effect to measure a gap between two conductive parts

An automated system for using eddy current edge effect to measure a gap between two aircraft conductive parts, the automated system comprising:

• two aircraft conductive parts, each having a plurality of predetermined properties comprising a material type, a material thickness, and a diameter of a through hole formed through each of the two aircraft conductive parts;
• an eddy current probe comprising a housing with a coil mounted within the housing, the eddy current probe configured to contact the two aircraft conductive parts to take a gap measurement comprising a gap width of the gap between the two aircraft conductive parts;
• a reference gap standard, based on one or more reference gap measurements, taken between at least two reference conductive parts separated by a gap distance, as specified by predetermined engineering requirements;
• and
• an inspection instrument assembly coupled to the eddy current probe, the inspection instrument assembly comprising an oscilloscope calibrated to the eddy current probe and to the reference gap standard, and comprising an alarm device,
• wherein the eddy current probe is inserted into the through hole formed through each of the two aircraft conductive parts, and the eddy current probe with the coil uses the eddy current edge effect to take the gap measurement comprising the gap width and measure the gap between the two aircraft conductive parts, and
• further wherein the gap measurement is compared to the reference gap standard, to determine whether the gap measurement is an acceptable result or an unacceptable result, based on the predetermined engineering requirements, and wherein the alarm device is activated when the gap measurement that is taken is the unacceptable result.

A method for using eddy current edge effect to measure a gap between two conductive parts, the method comprising the steps of:

• determining a plurality of predetermined properties for the two conductive parts, the plurality of predetermined properties comprising a material type, a material thickness, and a diameter of a through hole formed through each of the two conductive parts;
• selecting a probe, based on the plurality of predetermined properties of the two conductive parts, to optimize a gap measurement taken with the probe, wherein the probe comprises a housing with a coil mounted within the housing;
• selecting a reference gap standard, based on one or more reference gap measurements, taken between at least two reference conductive parts separated by a gap distance, as specified by predetermined engineering requirements;
• calibrating an inspection apparatus to the probe and to the reference gap standard;
• inserting the probe into the through hole formed through each of the two conductive parts, and the probe with the coil using the eddy current edge effect to take the gap measurement and measure the gap between the two conductive parts;
• comparing the gap measurement to the reference gap standard, to determine whether the gap measurement is an acceptable result or an unacceptable result;
• and
• accepting or rejecting the gap measurement, based on the comparing step and based on the predetermined engineering requirements.