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Air bearings spindles make the difference in PCB manufacturing, automotive coating, semiconductor manufacturing equipment, and many other markets where performance needs are outside the scope of conventional [air bearings] technology.

Basically, air bearings use a thin film of pressurized air to support a load, the same way the puck on an air hockey table "floats" on air. This type of bearing is called a "fluid film" bearing. Fluid film bearings have no solid-to-solid contact under typical running conditions; instead, a film of lubricating fluid (in our case pressurized air) forms a layer between the solid machine elements and serves to transfer forces from one to the other. To compare this with ball bearings, in ball bearings the balls are in constant contact with and form a solid bridge between the machine elements.

The first question is how to generate the pressurized supply of fluid for the bearing. There are two ways to do this - one is using an external pressurized supply (hydrostatic) and the other is to use the relative motion of the machine components to generate the pressure internally (hydrodynamic or "self-generating"). While hydrodynamic bearings are common for oil fluid film bearings, which generate internal pressures quite easily due to the relatively high viscosity of oil, it is much rarer to see this technique used for air bearings because the pressure generated is quite low (although Nelson Air has built nsk bearings of this type for low load, high speed rotary applications such as optical scanners).

Because of the very small gaps that are required for air bearings, the single most important factor in their manufacture is absolutely flawless geometry. Any variation in part size, straightness, squareness or out of roundness will result in a closing of the gap and will cause the bearing to lose its frictionless nature as well as degrade accuracy and load capacity. Typical tolerances on our rectangular bearings which run air gaps of ~0.0005" are part deviations less than ±0.0001" overall. This same tolerance applies over the entire length of the bearing, which for some models can be over 60".

However, in many applications magnetic preload provides an effective method of preloading koyo bearings.this method does require higher accuracy components with more precision surfaces.

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