The Ultrasonic transducer

An ultrasonic transducer is a device that is capable of generating and receiving ultrasonic vibrations. An ultrasonic transducer is made up of an active element, a backing, and wearplate.

 The active element is a piezoelectric or single crystal material which converts electrical energy to ultrasonic energy. It can also receive ultrasonic energy and converts it to electrical energy. The electrical energy pulse is generated from an instrument such as a flaw detector.

The backing is most commonly a highly attentive and very dense material and is used to control the vibration of the transducer crystal by absorbing the energy that radiates from the back face of the piezoelectric element. When the acoustic impedance of the backing material matches that of the piezoelectric crystal, the result is a highly damped transducer with excellent resolution. By varying the backing material in order to vary the difference in impedance between the backing and the piezoelectric crystal, a transducer will suffer somewhat and resolution may be much higher in signal amplitude or sensitivity.

The main purpose of the wearplate is to protect the piezoelectric transducer element from the environment. Wearplates are selected to generally protect against wear and corrosion.

Ultrasonically assisted turning:

Ultrasonically assisted turning is a metal removal technique, in which the cutting edge of a tool vibrates at a regular frequency within an ultrasonic range. There are three independent principle directions, in which ultrasonic vibration can be imposed in a turning operation. These include the feed direction, cutting direction and the radial direction.

The application of ultrasonic vibration along the feed direction enables the cutting parameters used in manufacturing industry for most materials to be reached independently of the workpiece diameter.