Static and Dynamic Characteristics of Magnetically Preloaded Air Bearing Stage for a 3-Axis Micro-Machine Tool

3축 마이크로 공작기계용 자기예압 공기베어링 스테이지의 정, 동적 특성

In this paper, the static and dynamic stiffness of the air bearing stage for micro-micro machine tool are examined experimentally. For stiffness and precision concerns, air bearing stages are adapted for 3-axis micro-milling machine which is size of $200x200\;mm^2$. The air bearings in the stage are preloaded by permanent magnets to achieve desired bearing clearance and stiffness for vertical direction. As the stiffness of the air bearing is primary interests, static stiffness test were performed on XY stage in Z direction and Z column in Y direction. Dynamic test were performed on XY stage and Z column, respectively. Both static and dynamic tests were performed in different air pressure conditions. The vertical stiffness of XY stage is about 9 N/ pm where Y stiffness of Z column is much smaller as $1\;N/{\mu}m$ because of the large moment generated by Y force on the column.