The influence of external load and air pressure on air slide table performance of ultraprecision machines in nanomachining

In nanomachining, which is a relatively new technology in cutting category, applied device is an ultraprecision machine. In this machine there are two main subassemblies creating rotational and linear motions, air spindle and linear air table, respectively. The linear air table has been simulated experimentally by a linear air bearing. This bearing creates motion in main direction of X and has straightness error motions in Y and Z directions as well. There are also rotational errors around X, Y, and Z axes. The errors are variable according to different parameters. This investigation studies on the rotational errors and deals with the influential parameters and their proportion. As far as the two mating surfaces are separated by a thin layer of pressurized air, the air pressure, the location, and amount of external load are some of the parameters which have been studied. Results show that the more air pressures, the more stable and stiff table is obtainable. Moreover, there will be less error motions. The error amount is not similar in X, Y, or Z direction. Finally the best air pressure and external load and load location have been derived.