Design And Optimization Of Carrying Unit On Negative Pressure Adsorption Floating Platform

With the development of LCD flat panel technology,people pay more attention on the transmission and online detection of large-size LCD flat-panel.The traditional ways have been unable to meet the actual needs of production.Since the 7th generation production line,the contactless airborne transmission and detection platform is applied to the flat panel for transmission and detection.According to different ways of compressed air supply,the air floated platform is divided into positive pressure air platform and negative pressure adsorption gas floating platform.The latter has a positive and negative pressure staggered arrangement at the exit.Therefore,compared with the former,the pressure distribution in the air film is more stable,more suitable for the liquid surface of the LCD screen defection(accuracy of 1?m)on-line detection system.In this paper,the structural model of the negative pressure adsorption gas flotation platform is established.Because the air-floating characteristics of the flotation platform are closely related to the structural parameters of the flotation platform itself and the geometrical parameters of the orifice,Through the numerical simulation,the ideal parameters of the relevant structure of the flotation table are obtained,so as to ensure the high stability of the air gap of the negative pressure adsorption type floating platform.The CFD(Computational Fluid Dynamics)technique is used to divide the mesh and simulate the calculation.Through the post-processing,observe the distribution of pressure,velocity,mass flow and bearing capacity in the basin.By changing gas source pressure and the size of geometric parameters,explore the variation law of the static characteristics of the fluid.It is concluded that the gas source pressure and the film thickness have a great influence on the gas static characteristics.The bearing capacity of the film is proportional to the change of the positive pressure,which is inversely proportional to the change of the negative pressure and the thickness of the film.The influence of the small change of the orifice and the throttle on the static characteristic is not obvious.The largest pressure drop in the basin is at the bend-like throttling and the pressure is stable before the gas reaches the film.Imports and exports of mass flow equal,and negative pressure exports accounted for about 35% of imports,the rest into the atmosphere.The results of the simulation have a positive effect on the structural design of the flotation platform,There are many other factors that affect the static pressure characteristics,such as the angle of the corners of the curve,the arrangement of the orifice,Therefore,how to get the optimal results also need to carry out a lot of research and experiment.