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Adherence to the following guidelines will help you obtain maximum performance and lifetime from your piezo actu-ators: Do not use metal tools for actuator handling. Do not scratch the coating on the side surfaces. The following precautions are recommended during handling of piezoelectric actuators:
I. Piezoelectric stack actuators without axial preload are sensitive to pulling forces. A preload of up to 50% of the blocking force is generally recommended.
II. Piezoelectric stack actuators may be stressed in the axial direction only. The applied force must be centered very well. Tilting and shearing forces, which can also be induced by parallelism errors of the endplates, have to be avoided because they will damage the actuator. This can be ensured by the use of ball tips, flexible tips, adequate guiding mechanisms etc. An exception to this requirement is made for the PICA™-Shear actuators, because they operate in the shear direction.
III. Piezoelectric stack actuators can be mounted by gluing them between even metal or ceramic surfaces by a cold or hot curing epoxy, respectively. Ground surfaces are preferred. Please, do not exceed the specified working temperature range of the actuator during curing.
IV. The environment of all actu- ators should be as dry as possible. PICMA® actuators are guarded against humidity by their ceramic coating. Other actuators must be protected by other measures (hermetic sealing, dry air flow, etc).
The combination of longterm high electric DC fields and high relative humidity values should be avoided with all piezoelectric actuators.
V. It is important to shortcircuit the piezoelectric stack actuators during any hand- ling operation. Temperature changes and load changes will induce charges on the stack electrodes which might result in high electric fields if the leads are not shorted: Should the stack become charged, rapid discharging—especially without a preload—might damage the stack. Use a resistor for discharging.
VI. Prevent any contamination of the piezo ceramic surfaces with conductive or corrosive substances. Isopropanol is recommended for cleaning. Avoid acetone and excessive ultrasonic cleaning at higher temperatures.
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