Rotary stage claims to redefine accuracy

ABR1000 ultrahigh-precision rotary stages combine air bearing technology and direct-drive slotless/brushless servomotors to provide unsurpassed error motion, wobble performance and velocity stability.

Aerotech's ABR1000 ultrahigh precision rotary stages combine air bearing technology and direct drive, slotless/brushless servomotors to provide unsurpassed error motion, wobble performance and velocity stability for high-throughput production and test applications such as MEMS (microelectromechanical systems).

MEMS is a specific area of nanotechnology concerning the integration of submicron mechanical elements, sensors, actuators, and electronics on a common silicon substrate through various microfabrication techniques.

This rapidly evolving technology demands enhanced-precision automated mechanical systems capable of providing highly stable, accurate and repeatable positioning platforms.

The ABR1000 is also well suited to other demanding manufacturing and test applications such as wafer inspection/singulation, DVD mastering, disk drive test/servo writing, optical inspection and fabrication.

The ABR1000's brushless, direct drive motor features a patented magnetic circuit to produce high torque with minimal heat, which is essential for nanometre positioning applications.

The motor's slotless design provides zero-cogging and torque-ripple-free performance resulting in exceptionally smooth velocity control throughout its 0 to 500rev/min speed range.

In addition its high acceleration capability, in-position stability and inherently zero backlash is perfectly matched to high throughput electronic manufacturing applications.

With a nominal diameter of 175mm and overall height of just 100mm, the air-bearing surfaces within the low profile design have been maximised to ensure high-stiffness and high axial and radial load capacities of 650 and 350N, respectively, with an overhung loading of 28Nm (tilt).

The ABR1000's specification for axial and radial error motions are better than 20nm asynchronous and better than 100nm synchronous, measured to ANSI/ASME standards.

These figures are unsurpassed for commercially available rotary air-bearing stages and are complemented with equally impressive tilt errors resulting in face error motions and a total planar performance which is significantly better than other manufacturers' air-bearing tables and rotary spindles available today.

Directly coupled encoder feedback options for the ABR1000 include noncontacting, reflective and interferential types depending on the resolution and accuracy requirements demanded by the application.

When combined with Aerotech's feedback multipliers and controls, they can provide calibrated angular resolution to less than 0.03arc-sec and positioning accuracy to less than 1arc-sec.

ABR1000 air-bearing stages are constructed in aluminium with a patented, Rockwell 62, "hard coat" Teflon impregnated finish for maximum durability.

The tabletop and base is supplied predrilled with several mounting holes and features a 35mm diameter through-hole for product feed through.

The noncontacting, air-bearing design means extremely long life and practically zero maintenance.

A wide range of options available for the ABR1000 includes integral wafer chucks, disk chucks and clamps, accessories for ESD (electrostatic discharge) wafer fabrication and rotary unions for air and vacuum service.

Customisation options include rate table and inertial guidance test stands.

In many applications the stage would form a part of fully integrated automation systems supplied by Aerotech and would typically include other positioning stages, motion and machine controls.

ABR1000 rotary stages are supplied as self-contained units with all motor and encoder feedback connectors integral within the housing keeping the overall footprint to a minimum.

All performance and calibration related documents and a CD with complete interconnection drawings are included along with motor parameter setup data for the software configuration file to suit the control and drive selected.

Aerotech builds these features into all of its products ensuring that the true cost of ownership is extremely competitive and that system commissioning is straightforward, requiring little more than connecting cables and applying power before programming application software.

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