Quality inspection of grooves using ultrasonic beams

A highly accurate non-contact displacement instrument based on the ultrasonic time-of-flight principle has been developed. The instrument uses stabilised air-flow to compensate for temperature and humidity variations. New signal processing electronics and reduction in the signal footprint using filters enable measurements to occur on curved and rough surfaces as well as accurate determination of groove dimensions. Initial tests have shown that the instrument is capable of displacement measurements with an accuracy of 25 μm when used on flat composite materials