The sound frequency used in these is usually in the range of one hundred kilohertz to fifty megahertz that is way above the normal human hearing range of twenty thousand hertz. Sound generated at these frequencies has a shorter wavelength that can reflect small surfaces and enable it to detect the defects inside solid materials such as metal and plastic.
These devices use Piezo or ferroelectric material as an active element to detect flaws by converting the excitation pulse (electrical energy) generated from the flaw detector into ultrasonic energy. The transducer’s performance is enhanced with the use of materials such as Piezo polymers and composites that are capable of producing different wave modes, by cutting the ceramics in different forms. These devices contain a backing component made from high density material to absorb the energy radiated from the active element’s back face, and control the vibration of the transducer. They … Read the rest