PPA's Selection Guide

CEDRAT Piezoelectric Actuators

Direct Piezo Actuators (DPAs) are the most common type of pre-stressed Actuators. They consist of a stack of pre-stressed active material. Conventional DPAs use a serial pre-stress. The level of pre-stress determines the pulling force capability.

A more robust technique (widely used at CEDRAT Technologies in power ultrasonic transducers) consists of a parallel pre-stressed with a bolt-tightened steel rod. However, this approach requires multilayer actuators having ring shape, which are less common and more expensive.

A third alternative consists in pre-stressing the actuator through an external elastic frame, leading to a Parallel Pre-Stressed Actuator, PPA.

DPA and PPAs are solid-state linear Actuators. They use only the expansion of the active material in the "33-mode" thus producing a useful displacement. This displacement is proportional to the voltage on a 170V range. Typically, the Actuator deformation is about 0.1% (1um/mm), so their displacements are limited to about 100um. In counterpart, the forces are naturally large, easily higher than 1kN. DPAs are using a conventional series pre-stress, so they are limited to quasi-static applications such as micro positioning. 

Examples of some CEDRAT PPA Actuators Series

PPA M Series

PPA L Series

PPA XL Series