![]() 200μm (typically 500μm) because of the machining processes and the fragility of the ceramic material. The minimum layer thickness is limited to approx. ![]() Using bulk technology, ceramic cylinders or blocks are pressed and sintered, then separated into discs, plates or tubes, provided with electrodes and glued to form actuators such as benders or linear piezo stacks (PIC product lines: PICA stack, PICA shear, etc.). The techniques can be divided into two categories: 1) pressing/sintering (bulk) technology, 2) film technology. PI Ceramic (PIC) has access to a wide range of technologies for producing piezoceramic actuators. Additional performance gains can be made by piezoceramic multilayer actuator components that have been optimized for highly dynamic applications.Ģ Basics 2.1 PICMA® Multilayer Actuator Technology The optimum utilization of piezoelectric multilayer actuators in applications such as adaptive systems and active vibration cancellation operating with bandwidths in the kHz range requires an efficient way to dissipate the resulting heat away from the actuator. Īt large signal amplitudes, the maximum achievable repetition rate (operating frequency) of piezo mechanisms is often limited less by the mechanical resonant frequency than by the self-heating effect of the actuators due to their internal dielectric losses. Application examples include piezoelectric inkjet printers, piezoelectric fuel injection systems, dispensing devices, adaptive tools, and micro pumps. In addition to ultra-short mechanical switching times in the microsecond range, piezo actuators have been used with repetition frequencies of hundreds of Hz at full displacement amplitudes. Other applications are based on the extreme dynamics of the generated mechanical signals. Advantages are friction-free movement with almost infinitely high resolution, high blocking forces, compact design, and high energy efficiency in quasi-static operation. These multilayer actuators are used in different applications including precision motion control. In order to increase the limited induced displacement of individual piezoceramic layers, actuators are generally produced from many stacked layers. The resulting deflection signal is a superposition of contributions from purely piezoelectric ionic displacements and reversible ferroelectric reorientations. The active principle is based on the inverse piezoelectric effect, in which a mechanical deformation is produced by the application of an external electric field in poled piezo-ferroelectric ceramics. Piezoelectric actuators have become the leading electromechanical solid-state actuator technology in the last 25 years. With a newly developed amplifier, nominal displacement of 35µm at 3,300Hz was demonstrated with actuator temperatures not rising above 80☌. In addition, an improved hermetically sealed piezoceramic multilayer actuator suitable for liquid cooling is proposed. This paper describes the results of self-heating tests for various cooling measures. The control frequency is generally limited by the heat generation of the actuator due to its dielectric losses and can be increased by passive and active cooling measures. Rise times significantly less than 100μs and repetition frequencies in the kHz range are state of the art and are used in applications such as fuel injection, ink jet printing, adhesive dispensing, active vibration damping or in adaptive tools. ![]() Electromechanical conversion in piezoceramic solid-state actuators can generate highly dynamic motion.
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