Analysis On Performance Of Gas Squeeze-film Levitation Stage

Gas squeeze-film levitation stage is one kind of supporting component. When the piezoelectric disc vibrats along the normal of the stage surface in high frequency, gas in the gap between the piezoelectric discs and the upper plane will be squeezed, and the gas squeeze-film will be built. And then the stage has the carrying capacity. This stage has some advantages such as almost no friction, no pollution, little heat, tiny movement error.It is may be widely used in high precision instrument and micro-electronics processing. In this paper, the mathematic model of gas squeeze-film was established based on the air dynamic equations and was resolved by numerical difference method, the carrying capacity was got by numerical integral method. A calculation program was developed in FORTRAN. Then some static and dynamic characteristics of gas squeeze-film such as pressure distributing, the carrying capacity, stiffness and damping were given. The relations between the performance of gas squeeze film and its influence factors were discussed too, the influence factors included the radius of piezoelectric discs, drive frequency, original thickness of the gas squeeze-film.The hardware of the squeeze film driving circuits were also designed and made. Then the programme of the driving circuits was developed. The functions of the circuit included drive, test and frequencies adjust. At last the vibration and frequency of piezoelectric discs were tested and the technics of the stage were studied in primary too.The research conclusion indicates that the stage studied in this paper can built squeeze gas film with certain load capacity within permit film thickness, when the radius and frequency of piezoelectric disc become larger, the carrying capacity, stiffness coefficients, and damp coefficient are larger during a cycle.