Posted to News on 18th Apr 2008, 12:03
Compact positioning table outperforms alternatives
Now available from Micromech, the URS single-axis positioning table integrates a linear bearing and precision ball screw, making it compact and, according to the company, able to outperform conventional positioning tables.
This is made possible by a U-shaped steel guide rail and a recirculating bearing module that provides the dual functions of a guide block and a ball screw nut. The U-shaped guide rail offers a rigid structure that is resistant to bending, enabling the URS to be supported only from a single end. In addition, the bearing module contains four ball circuits that deliver high load capacity, accuracy and rigidity.
The integration of the slide guide and precision ball screw eliminates complex precision adjustment and therefore reduces installation time, as it avoids the purchase and assembly of individual components.
Each URS shuttle carriage contains four ball circuits and four-point contact ball grooves, which also contribute to excellent rigidity. This, plus the combination of precision ground guide rail, carriage and precision grade ball screw, provides high positioning accuracy.
Furthermore, the U-shaped guide rail and integrated carriage/ball nut design result in a compact package that provides dramatic space savings in comparison to conventional positioning tables. The four-row linear bearing structure maximises the rigidity of the carriage, enabling the URS to be mounted in any orientation.
Sizes and options
The Danaher URS (with cover) can be supplied in travel lengths from 43-1134mm. It covers a wide range, from standard and short version carriages to single- or dual-carriage options for increased flexibility of load carrying. There are either the commercial-grade version with repeatability down to +/-5um or the precision-grade version with repeatability down to +/-3um. Loads of 9, 30 and 140kg for the commercial grade and 9, 30 and 90kg for the precision grade can be carried.
The tables accommodate both servo and stepper motors with flanges for NEMA 16, 17, 23 and 34 frame motors. There is a hard cover available to protect internal components and to contain lubricant, and a clean room grease option for particulate-sensitive environments.
Further options include limit switch packages with three sensors adjustable throughout the range of travel and a Raydent surface treatment option for improved rust-resistance of the steel rail.
Although it has a compact profile, its structure and high stiffness make it suitable for one-end supported (cantilevered slide) applications. The tables are excellent for use in semiconductor, flat-panel display, data storage, digital imaging, transport, machine automation and life science applications.
