Precision worm-drive rotary stages last 10 times longer

Paul Boughton
Aerotech is launching a new range of precision worm-drive rotary stages featuring large through-apertures and a patent-pending preload arrangement that is said to provide outstanding levels of accuracy and repeatability with minimal wear and an order-of-magnitude increase in stage life over competitive gear-driven rotary stages.

The AGR series encompasses five models with internal diameters from 50 to 200mm and is available with continuous 360 degree travel or with a mechanically limited travel range (down to 5 degrees). Axial load capacity is up to 570kg and rated speed to 30rpm; the range also includes optional directly mounted encoders for improved repeatability and negligible levels of hysteresis and backlash.

Typical specifications across the AGR series include a 120 arc-sec positional accuracy without encoder fitted and 20 arc-sec when the servomotor-mounted encoder option is used. Corresponding without- and with-encoder specifications for bidirectional repeatability are 30 arc-sec and 8 arc-sec. Stage resolution, with a 2500-line servomotor-mounted encoder fitted on the largest stage, is 2.1 arc-sec, while the same sized stage with a directly mounted 40,000 lines-per-revolution encoder achieves 32.4 arc-sec.

Aimed at general-purpose rotary positioning applications in research, industrial production and manufacturing test applications, the AGR series has been designed to accommodate the through-aperture mounting of additional equipment and services such as lenses, mirrors, slip rings or cable assemblies on high-precision positioning systems.

The main housing and table top are manufactured from a special lightweight aluminium alloy that ensures high structural stiffness and a reduced mass for multi-axis assemblies and other weight-critical applications. The AGR series also benefits from dual preloaded angular-contact bearings to provide the high load handling required for offset and awkward payloads, whil maintaining the minimal error motion performance required for high-precision positioning.

Other AGR series options include a wide choice of Aerotech's high-performance brushless servomotors or stepper motors in various orientations with rear shaft-mounted encoders and brakes. A labyrinth sealing kit is also available for stage sealing in arduous machining environments, and vacuum-compatible versions are available for levels down to 10-6 torr.

For more information, visit www.aerotech.com

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