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Mini actuator delivers nanometre accuracy

05 October, 2007

Physik Instrumente (PI) has developed a miniature ceramic linear motor actuator which, it claims, bridges the gap between micropositioning and nanopositioning devices.

PI Nexact actuator

The Nexact actuator (shown above) can deliver push or pull forces of up to 10N, speeds of up to 10mm/s, and travel lengths up to 20mm. Unlike servo or stepper actuators, the piezo stepping elements produce linear motion directly, without needing to transform rotational motion using gears or leadscrews. This eliminates backlash and wear, resulting in a maintenance-free drive.

The non-magnetic actuator weighs just 50 grams and fits in a package measuring 25 x 25 x 12mm. It exhibits high stiffness and is self-locking when powered down.

In operation, piezoceramic bending elements act on a ceramic runner connected to the application’s moving part. The length of the runner can be chosen to suit the application. For travel distances below 7µm, a linear mode allows high-dynamic positioning with resolutions better than 1nm. For longer distances, a stepping mode is used.

The patented actuators are expected to find applications in areas such as semiconductor manufacturing, test equipment and biotechnology.