Structure Optimization Design And System Stability Analysis Of Micro-hole Array Aerostatic Motorized Spindle

With the rapid development of science and technology,electronic products are gradually becoming compact,convenient,and multifunctional.The requirements of the new batch of electronic products for PCB circuit board are becoming more and more strict.Therefore,the need for higher accuracy and quality of the PCB circuit board.Thus,the accuracy of its processing equipment is also more stringent.Usually when drilling PCB circuit board micro-holes,the first choice is the high-speed drilling of CNC machine tools.Because it’s high accuracy,high efficiency and high quality ensure the accuracy of drilling requirements.For most CNC machines that process PCB boards,the core structure is an aerostatic bearing.Air-static bearing has the characteristics of high precision,small vibration and long life,etc.Taking the NC drilling machine of PCB circuit board as the research object,this paper mainly analyzes the structure of the aerostatic motorized spindle.And on the basis of the existing structure,this paper designs a new type of air hydrostatic bearing-microhole array air hydrostatic bearing.The dynamic and static characteristics of the bearing are analyzed,and the support structure of the new bearing is optimized.The main research content of this article has the following aspects:Firstly,According to the theory of gas lubrication,the general equation of gas Reynolds is established.The static analysis of microporous array aerostatic bearing is carried out by using FLUENT software of finite element analysis software ANSYS Workbench.According to the analysis of pressure diagram,the influence of different types of microporous array throttle on the stability of motorized spindle can be compared,and the optimum structure of microporous array throttle can be selected from it.Secondly,On the basis of selecting the optimum structure of the microporous array throttle,the static performance analysis of the main structural parameters of the microporous array bearing is carried out.The curves of bearing load capacity and stiffness change under different parameters are obtained,from which the microporous air bearing with the best parameters is selected.Thirdly,Optimize the microhole array type air motor spindle support structure.By combining the stiffness theory with the analysis of equations,a multi-support structure is proposed.The radial stiffness of the motorized spindle is analyzed by using the fluid-solid coupling analysis method of the Workbench software.According to the analysis results,the stiffness of the multi-support structure is higher than that of the double-bearing structure,and the more the support is near the front bearing,the better the rigidity of the motorized spindle is.Thirdly,In this paper,the modal analysis and harmonic response analysis of microporous arrayed air hydrostatic motorized spindle are carried out.Firstly,through the modal analysis,the natural frequency and mode shape of the micro-hole array aerostatic piezoelectric main shaft in the low-order modes are obtained,and the critical speed is calculated.Then,the harmonic response analysis is performed to obtain the displacement response of the electrospindle front end;Finally,the modal analysis is verified by experimental methods to verify the reliability of modal analysis simulation.