Structural Optimization Design And Dynamic Characteristic Analysis Of Super-high Speed Static Pressure Air Floating Electric Spindle

The demand for consumer electronic components continues to increase with the rapid development of the information and communication industry,and the demand for the scale of PCB circuit boards is also increasing.To achieve the high efficiency of more and more ultrasmall holes on PCB boards,High-precision machining needs are often achieved with ultra-highspeed static pressure air float electric spindles.However,the domestic ultra-high-speed static pressure air-floating electric main shaft has large vibration during high-speed operation,the bearing capacity and stiffness of the air-floating bearing are small,and the dynamic stability is insufficient.It cannot continue to guarantee the processing accuracy and efficiency of the PCB board.In this paper,a new form of shaft support structure is proposed,which will directly affect the dynamic stability of the ultra-high-speed static pressure gas-floating electric main shaft system and propose a new form of shaft support structure.After verification,the scheme is reasonable and feasible.The specific research and analysis of this article are carried out from the following aspects:1.Based on the theory of gas lubrication,a simple analysis and derivation of the general mathematical model of gas lubrication,including Navier-Stokes equations,equations of state,continuity equations and the general form of the Reynolds equation.Combining gas lubrication theory with air bearing,a mathematical model of gas film pressure distribution that can calculate the bearing capacity and stiffness of air bearing is established.2.The three-dimensional modeling software CREO is used to establish a threedimensional simulation analysis model of the main shaft bearing.The FLUENT module in the finite element analysis software ANSYS-Workbench is used to simulate and analyze the main shaft air bearing bearing to study the air bearing radial bearing and thrust bearing.For static characteristics,the interaction between bearing capacity and stiffness and other parameters is studied.A structural parameter scheme with both a certain bearing capacity and a certain rigidity is selected.3.Introduced several common spindle system support structure layouts in detail,and proposed a new spindle support structure form.The three-dimensional modeling software CREO was used to carry out full-parameter entity modeling of the above several forms,and the gas The fluid domain is solidified,and the fluid-solid coupling mechanical analysis method is used to analyze the deformation of several different support structure layout forms of the highspeed spindle.The simulation analysis results show that the newly proposed spindle support structure is the one with the least deformation and the best dynamic stability.The solution is a structure with two supports at the front and two supports at the rear.4.Establish a three-dimensional solid model of the complete shaft core part of the ultrahigh-speed static pressure air float electric main shaft,and use the ideas of fluid-solid coupling mechanical analysis to conduct modal analysis and harmonious response analysis,and study and obtain the third-order modal of the shaft core.And its vibration type and natural frequency,the dynamic response of the displacement of the front end of the shaft core under the action of external excitation force,provides a supporting basis for the working stability of the main shaft.5.The actual experimental test was carried out on the ultra-high-speed static pressure airfloating electric spindle with a maximum target speed of 180,000 rpm.From the measured vibration and run-out data of the electric spindle,the data were within a reasonable range,which verified the previous simulation analysis.Rationality and reliability.