A cymbal transducer for power ultrasonics applications

Abstract

The flextensional class V ‘cymbal’ transducer has been widely adopted for low power ultrasonics applications, exhibiting high output displacement for low input energy, compared to a single ceramic, when used as an actuator. Despite its performance benefits, the original designs of cymbal transducers have inherent drawbacks for high power ultrasonics applications that require much higher output displacements. Asymmetries introduced during the fabrication process reduce the efficiency of the transducer, and degradation of the bonding layer between the end-caps and the electroactive material can alter the vibration response and ultimately lead to failure. A new design of the cymbal transducer is therefore proposed that delivers high output displacements. A comparison is presented between a cymbal based on the original design configuration and a new cymbal, to demonstrate the effects of input voltage levels on the dynamic characteristics and vibration response of the two different transducers. For the first cymbal the end-caps are directly bonded to the piezoceramic disc using a commercial non-conductive epoxy. The second cymbal incorporates a metal ring bonded to the outer edge of the piezoceramic disc to improve the mechanical coupling with the end-caps, thereby enhancing the operational capability of the device at higher voltages, allowing for excitation of higher output displacements by removing the problems associated with failure in the epoxy layer. This design is demonstrated to be particularly suitable for power ultrasonics applications such as miniature surgical devices, for example as drilling and cutting devices for orthopaedics procedures.