In a feed-through encircling coil flaw detection system, why would you run a calibration defect several times in different positions?

Running a calibration defect several times in different positions in a feed-through encircling coil flaw detection system is essential for ensuring proper centering of the material in the test coil. Proper centering is critical because it affects the accuracy and reliability of the measurements taken by the coil. If the material is not well-centered within the coil, it can lead to variations in the induced currents and magnetic fields, which in turn can result in inconsistent signal readings and potential misinterpretation of the presence or absence of flaws.

By calibrating with defects at various positions, operators can verify that the system is capable of detecting flaws consistently, regardless of where they occur within the effective testing area of the coil. This method enables the technician to account for any potential variations in the detection capability based on position, thus enhancing the overall operational reliability of the flaw detection process.