General purpose motion applications are perfectly well-served by mechanical bearing solutions like recirculating ball bearings or crossed-roller bearings, but there are many cases where precision, angular repeatability, and geometric performance must be optimal. An air-bearing stage can help achieve this. An air-bearing stage is either a rotary or linear positioner that floats on a cushion of air, using one of several preload mechanisms, nearly eliminating mechanical contact and thus wear, friction, and hysteresis effects.These are the most common indicators that an air-bearing stage might be the right choice for your application.

1. High-Precision Positioning

A direct-drive motor and high-resolution encoder can position a moving carriage supported by an air bearing to within nanometers in a linear case or arc-seconds in angular cases. The lack of friction and mechanical contact means there is minimal hysteresis or reversal error, making it highly repeatable and ideal for many inspection and manufacturing operations.

2. Velocity Stability

The lack of mechanical bearing elements means there is nothing to get in the way of smooth, controlled velocity (stability to better than 0.01%). Experiments and processes like inertial sensor testing, tomography, and work with Bose Einstein Condensates that require continuous motion at a tightly controlled speeds are best served by air-bearing systems.

3. Geometric Performance

The angular performance of an air bearing is remarkably repeatable. For linear stages, pitch, roll, and yaw errors can be as low as a few arc-seconds, and rotary stages have tilt (wobble) less than 1 arc-second. This guarantees optimal part quality and measurement reliability for applications like mirror and optics inspection, and semiconductor and medical device manufacturing.

4. Minimal Maintenance

There are no contacting parts to undergo wear and tear, and no regular maintenance procedures to be performed like lubrication. An air-bearing stage is essentially maintenance-free.

5. Perfect Match for Linear Amplifiers

Many applications like eddy current inspection, high-precision angular pointing, or anything involving noise-sensitive electronics require a linear power amplifier. As opposed to a pulse width modulated (PWM) amplifier, a linear amp exhibits no switching noise and filters out other sources of line noise to prevent interference with an experiment. Generally, if the level of measurement precision required necessitates a linear amplifier, it may also be best-served by an air-bearing stage to match that precision in positioning capability.

For more information on air-bearing stages including the pros and cons for your application, contact an Aerotech Applications Engineer and check out the options here.