PI (Physik Instrumente) LP Product
Nanometer Precise Direct-Drive Linear Motor Stage, High Speed Stage, V551 manufactured by PI for Automation Applications

The V-551 family of ultra-precision positioning stages models is equipped with precision crossed roller bearings featuring anti-creep cage assist and excellent guiding accuracy (1µm straightness / flatness per 100mm).
Two types of position feedback systems are available: absolute-measuring encoders providing 2 nanometers resolution and incremental encoders providing 0.2 nanometers resolution with effective 0.5nm minimum incremental motion at the stage platform.
Why ironless linear motors?
Ironless linear motors are used when high dynamics needs to be combined with extremely smooth motion. They are ideal for applications where extremely constant velocity is required, such as in optics inspection, metrology, photonics, interferometry, and semiconductor test equipment. The frictionless, zero-wear motor drives are also popular in fast automation applications, where reliability and maximum up-time are mission-critical.
Specifications, Datasheet, More Information
http://www.pi-usa.us/products/precision_positioning_pi-micos/Linear_Precision_Positioning_Stages_Mc.php#High_Accuracy
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