Very High Load Capacity Air Bearing Spindle for Large Diamond Turning Machines

摘要

Spindles for large diamond turned mirrors are not readily available. Oil hydrostatic spindles that are large enough to carry the load cannot run fast enough because of the heat generated by viscous forces. Air bearings have the potential to meet the speed requirements due to the lower viscosity. Classic metal-to-metal air bearings are expensive at large sizes and can fail catastrophically. Porous graphite bearings have the potential to resolve these problems. Preliminary requirements have been identified for a bearing to support a 3 meter mirror. Discs of porous graphite have been prepared for flow testing and a surplus air bearing rotary table has been located. A prototype spindle has been designed to work with the table.