simulation of air pad shape on pressure distribution in air gap of air table in ultra precision machine tools

air pads are applicable in ultra precision machines very much. two main components of these machines, spindle and table, use the advantages of such systems. the performance and efficiency of air pads have big influence on the whole machine quality. parameters affecting pressure distribution of air tables may be considered as, 1) air compressing method, 2) air nozzle diameter, shape, and size, 3) number of air pads, 4) air gap thickness, etc. in this study, effects of air pad shape on pressure distribution in air gap have been investigated using ansys. in this simulation, fotran environment have been employed. investigated shapes for air pads are triangle, rectangle, pentagon, hexagon, ellipse and circle. pressure distribution-distance from orifice has been plotted for each air pad shape. the results indicate that the rectangle air pad has best pressure distribution.