Content 7 Reasons Why Air Bearings Outperform Mechanical Bearings Video: How air bearings work. A planar XY air bearing stage with a built-in theta adjustment range for alignment or error compensation. Precision positioning and automation applications widely rely on high-performance motion stages and motion controllers. When it comes to developing a next generation machine or process, motion system designers often ask the question whether to employ mechanical bearings or air bearings. Mechanical bearings such as crossed-roller bearings, and recirculating ball bearings are widely used in precision motion control and positioning applications and are a good choice in most cases. However, in scenarios where parameters such as lifetime, particle generation, reproducibility, angular accuracy, runout, straightness, and flatness are critical, air bearings are superior and deserve a closer look. Air bearings use a thin film of pressurized clean air or gas to support the load, very similar to the principle of an air hockey table. There is no contact between the static and moving part of the bearing since the pressurized gas creates a layer separating both. There are two basic types of air bearings: porous media bearings with millions of sub-micrometer sized holes and bearings with small, integrated orifices. In both cases, the air bearing designers need to achieve a uniform pressure across the entire bearing area. Video: R-theta air bearing stages are often used in semiconductor test and metrology. Air bearing surfaces are precision-ground to the highest tolerances and hard coated. Since they do not come into contact (modern controllers with pressure reservoirs and switches shut down the motion in case of a pressure drop), they avoid traditional bearing issues such as friction, tribological wear, and relubrication. As a result, air bearings provide significant advantages in high-velocity motion applications and precision positioning, especially in 24/7 automation applications with high uptime and reliability requirements. 1. Maintenance-Free, Virtually Unlimited Lifetime, Clean Room Compatible: Since air bearings work without mechanical contact between components, they do not require maintenance, periodic inspections or relubrication cycles. There is also no cage migration issue known from cross roller bearings. And the systems are ideally suited for clean room applications. 2. True-Planar Motion XY and XY-Theta Motion Designs Feasible: Multi-axis stages with mechanical bearings usually stack one axis on top of another. This is a straight-forward approach but has several disadvantages. As the upper axis moves to the extremes, it will generate torque loads on the lower axis leading to geometric errors. In air-bearing designs, fully planar XY and XY-Theta positioning systems are feasible, where all degrees of freedom reference to the same base plane. 3. Vibration-Free, High-Speed Motion with Highly Constant Velocity: The fluid film in air bearings can readily accommodate high velocity, and some air bearings can even improve efficiency at high speed, due to aerodynamic lift effects. Certain processes and experiments, such as semiconductor wafer scanning, 3D tomography , and inertial sensor testing, demand constant motion at precisely controlled speeds, without bearing rumble. In these instances, air bearing systems are the most appropriate solution to provide the necessary continuous motion at precisely controlled speeds , and they generally last longer than mechanical bearings. Video: High speed linear actuator with air bearing guide 4. Frictionless Motion and Positioning with Very High Accuracy: In linear motion applications, precise positioning of a moving carriage within nanometers is achievable by employing a direct-drive motor and high-resolution encoder supported by an air bearing. For rotational applications, angular resolutions to tenths of arc-seconds are achievable. Air bearings are often preferred in many inspection, metrology, and manufacturing applications due to their minimal hysteresis effect or reversal error, which arises from reduced mechanical contact and friction. The elimination of friction makes it possible to minimize in-position hunting and improve resolution capabilities significantly. Although flexure guided piezo stages can achieve comparable precision, they are limited to much smaller travel ranges. Video: 3-axis air bearing stage for laser processing 7. Rotary Motion with Minimal Eccentricity and Wobble: Rotary air bearings are highly effective in providing precise rotary motion due to their exceptional stiffness. In rotary stages, wobble or tilt errors typically occur within the range of 0.1 to 1 arc-second. Compared to most mechanical bearing solutions, errors caused by wobble, axial and radial motions are much smaller. Sign up to receive an email of new blog posts. First Name* Last Name* Company / Organization City* State* Country* Email* Please read the following and confirm your consent to the processing of your data. By submitting this form, you consent to the PI Group contacting you through the communication channels you specify. Additionally, you acknowledge that the PI Group may store, process, and analyze the necessary data. For further information, see our >> Privacy Policy . Each email includes an unsubscribe link that allows you to withdraw your consent. 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