Monolithic rapid prototype flexured ultrasonic horns

Piezoelectric ultrasonic horn actuators are used in high power medical/surgical, automotive, food preparation, textile cutting, and material joining applications. Typically, these horn actuators are assembled by pre-stressing piezoelectric rings between the horn and backing layer using a pre-stress bolt. In the ultrasonic horn actuators presented in this paper the bolt was removed and the number of overall parts was reduced significantly allowing for easy fabrication and integration of the actuators into other structures. The elimination of the need for the conventional stress bolt internal to the piezoelectric stack and the reduction of the related complexity were achieved by using external flexures. The actuator structure was produced by an electron beam melting rapid prototype manufacturing process. This manufacturing process allows for horn structures with internal cavities if required. This design allows for using solid piezoelectric stacks (with no central hole) to produce a highly effective actuator. This paper presents the results of a novel design of a monolithic ultrasonic horn.