Air Bearing Benefits: Improved Surface Finish

The accurate, repeatable motion given by air bearing spindles gives a superior surface finish.

For applications, such as semiconductor processing, air bearing spindles provide a smooth, accurate, repeatable motion – resulting in a better surface finish. Unlike ball bearing spindles, air bearings provide constant bearing stiffness, ensuring minimal subsurface fracture in machining of hard materials. As the stiffness is produced by the uniform flow of air through the bearing, the reaction forces experienced by the shaft from an external load is constant at all points of its revolution. This property is particularly relevant to the production of good surface finish when grinding.

Typical surface finish:
Surface grinding - < 0.05 micron (2 micro-inch) CLA.
Diamond turning or fly cutting acrylics and soft metals - < 0.012 microns (0.5 micro inch) CLA, allowing consistent optical quality.

Air bearing stiffness values:
- Axial: up to 250 N/micron (1,400,000 lb/in)
- Radial: up to 580 N/micron (3,300,000 lb/in)

Comparison of rolling element and air bearing stiffness