The stiffness of the clamping mechanism in the actuation direction shall be as low as possible, typically under 1/10 th of the stiffness of the actuator, in order not to hinder the movement of the actuator. voltage) during loading/unloading, so it must be connected to a resistor or shorted at all times. When applying a force, be aware that the piezoelectric actuator will generate charge (i.e. For heavily loaded systems, higher pressures are required, typically 20MPa, sometimes up to 40MPa.
While unloaded actuators can safely be used in static conditions without preload, for lightly loaded, low dynamic applications we recommend to apply 5MPa clamping pressure. The clamping force must be adapted to the load on the actuator. The substrate must be clean, flat (<10µm depending on dimensions) and smooth (Ra 1.6µm). Stacked actuators are manufactured as a standard with 1mm top and bottom insulating ceramic end-plates which ensure two functions: Electrical insulation and better repartition of the load.įor clamping, most materials can be used, although materials with a high stiffness (steel, titanium) are preferred in order not to affect the overall stiffness of the system, i.e. Having inactive ceramic plates between the actuator and the opposing structure.įor linear actuators, it is recommended not to use a metal plate on top and bottom in order to avoid short circuit.Adding an insulator, for example polyimide tape on any conductive surface near the electrodes.The safe distance depends on the environment and voltage rating and can be in the range 0.1 to 1mm. Making sure that there is a sufficient distance between the electrodes and any conductive surface.Avoiding short circuit can be achieved by: When assembling it is important to stay clear from the surface electrodes in order to avoid arcing and short-circuit. The actuators may be mounted either by mechanical clamping or with an adhesive. Linear actuators are ground on top and bottom surfaces (perpendicular to the direction of expansion) as a standard in order to obtain flat and parallel surfaces for mounting.
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