Characteristic Studies Of X-Y Aerostatic Worktable Based On Box Plate

Along with modernized technical high-speed development,precision and ultra-precision motion guideways and motion worktable are playing a more and more decisive role in ultra-precision machining,optical precision measurement,semiconductor and other fields.Compared with the traditional 2-D worktable,it has higher accuracy and response speed,but it also has some problems such as small load,low stiffness and poor accuracy of biaxial perpendicularity.For this reason,this research lab independently developed a kind of precision measuring square box as the structural reference of the two-axis air floating worktable,its performance has a profound impact on the accuracy and efficiency of the workpiece machining measurement and subsequent workbench construction.Therefore,in order to accurately grasp the performance and characteristics of the air floating table,this paper proposes a method to deal with the air film gap at the angle coupling of the closed air floating guide.This method can be used for the overall calculation directly along the air film surface of the closed air floating guide different from the traditional closed aerostatic guideway,which are regarded as two relatively installed open aerostatic guideway,local calculation is carried out first and then the whole calculation,thus ignoring the influence of the gas film flow field at the corner.Firstly,this paper expounds the static aerostatic guideway of structural classification and working principle,According to the structure classification,it is concluded that the aerostatic guideway in this paper belongs to integral closed aerostatic guideway.Then,the overall structure layout design of X-Y aerostatic worktable based on square box is explained from four aspects,which are:Multi-hole integrated restrictor,X-axis aerostatic guideway,Y-axis aerostatic guideway,and Z-axis rack.Secondly,the static performance of X-and Y-axis static pressure air-floating guide in the air-floating worktable is studied by numerical calculation.This paper presents a coupling boundary adopts constant volume principle in the corner to simplify processing method,using the dichotomy accelerating convergence faster to flow in and out of balance in the process of numerical calculation,The static characteristic parameters of X and Y axis integral closed air floating guide are obtained by MATLAB software programming,and the optimal performance parameters are obtained through optimization.At the same time,the static performance of the two kinds of aerostatic guideway on the Y axis is compared.Through comparison,it is found that under the same air supply pressure and the sum of upper and lower bilateral clearance is certain,the stiffness and stability of the overall closed air static guide are better than that of the open aerostatic guideway.Then,based on the principle of micro-perturbation method,The dynamic performance of two types of aerostatic guideways on Y axis is studied.The dynamic governing equations of aerostatic guideway are established and derived.The governing equation is discretized by finite difference method.The influences of perturbation frequency and gas film thickness on dynamic stiffness and equivalent damping coefficient of two types of Y-axis aerostatic guideway are analyzed.Finally,a reasonable static and dynamic experimental scheme is designed to test two types of aerodynamic hydrostatic guideways on the Y axis.According to the experiment scheme,using the existing equipment of laboratory to carry out the experimental test work,and analyze the measured experimental test results.To sum up,Through the tests of the static and dynamic performance of the X and Y axis aerostatic guide way which is on the worktable,the correctness of the method which is proposed in the numerical simulation in this paper has been verified.and the overall pressure distribution,bearing capacity,stiffness and other properties of the closed aerostatic guideway can be calculated more accurately.It provides new guidance for the relevant design and study of the similar aerostatic guideway and aerostatic worktable,and it lays a solid basis for the follow-up improvement of the workbench.