Worm gear design offers increased precision

Aerotech has launched a range of precision worm drive rotary stages featuring large through apertures and a patent pending preload scheme said to provide high levels of accuracy and repeatability with minimal wear.

The AGR series covers five models with internal diameter from 50 to 200 mm 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; and the range includes optional directly mounted encoders. Typical specifications across the AGR series include a 120arc-sec positional accuracy without encoder fitted and 20arc-sec when the servomotor mounted encoder option is used. Corresponding without- and with- encoder specifications for bidirectional repeatability are 30arc-sec and 8arc-sec. Stage resolution, with a 2500 line servomotor mounted encoder fitted on the largest stage, is 2.1arc-sec - whilst the same sized stage with a directly mounted 40000 lines per revolution encoder achieves 32.4arc-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 designed to ensure maximum structural stiffness and a reduced mass for multi axis set-ups and other weight critical applications. Other AGR series options include a choice of Aerotech's 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 machining environments; and vacuum compatible versions are available for levels down to 10-6torr.