TOFD (Time of Flight Diffraction)
The TOFD (Time of Flight Diffraction) technique, as opposed to other ultrasonic techniques that use amplitude of ultrasonic wave reflected from discontinuities, uses signals created by diffraction waves generated on the edges of the defects. The TOFD technique is used, above all, to test welded joints. The whole process is digitally recorded which later makes it possible to repeatedly analyze and verify the test results. The TOFD method is characterized by high detectability of any defects with small number of false detections, it makes it possible to accurately measure the geometry of the discontinuities in three planes, and takes less time than the conventional methods.