Time of Flight Diffraction
Much like PAUT, TOFD also provides an easily stored record of the data, though interpretation of the results is less clear to the untrained eye. Regardless, TOFD is an especially powerful inspection technique for the investigation of both new and in-service welds.
How does it work?
Time-of-flight Diffraction (TofD) Ultrasonics uses two ultrasonic probes in a pitch-and-catch arrangement, with one probe dedicated to producing sound waves, and the other to receiving sound waves.
TofD relies on diffraction of the ultrasonic sound wave from the tip of a reflector to allow for more sensitive and accurate sizing of weld defects, regardless of orientation, which makes it an incredibly useful tool in conjunction with phased array ultrasonic testing (PAUT) for full weld inspection.