Why are calibration blocks used in phased array testing?

Calibration blocks are essential in phased array testing because they validate the accuracy of the ultrasonic equipment and ensure consistent performance throughout the testing process. These blocks are designed with known dimensions, material properties, and imperfections that replicate conditions found in the actual parts being inspected. By comparing the signals received from the calibration block to expected results, technicians can confirm that the equipment is functioning properly and producing accurate data. Proper calibration is crucial for reliable inspections, as it helps to identify any deviations in system performance before actual testing occurs.

While calibration blocks could provide visual references for training or contribute to simplifying the testing process, their primary role is to ensure precision and consistency in measurement, reinforcing the overall reliability of the phased array technique. Increasing inspection speed is a secondary benefit that may arise from effective calibration but is not the primary purpose of using these blocks.