In high precision system applications low friction levels between components are desirable. Moving heavy parts at high speeds and accelerations without friction is possible by using air bearings. The main failure ofthe air bearings is the wear phenomenon (modification of surface topography) that occurs due to crash into the counterpart when air supply is interrupted. The aim of this research is to investigate different types of air bearings for a large number of crashes using real operational parameters from the field: speed, acceleration, load and supply air pressure. The real crash phenomenon in a high precision machine hasbeen replicated using a test setup. During testing, evolution of air bearing surface topography and air bearing characteristics (gap and flow) after different number of crashes are investigated. Test results showthat some air bearings are not reaching the specified number of crashes due to large defects that occur on the bearing surface. Some specific relations were found between crash defects and parameters such asthe air gap size and the direct contact between opposing surfaces. The preferred type of air bearings shows good performance even above the maximum specified number of crashes. This behavior can be explainedby low friction level during crash tests between the opposing surfaces. The test results from this investigation produced a reliable candidate for air bearings in the high precision system application.
High precision system modeling of liquid crystal adaptive optics systems
