Study On The Dynamic Performance Of Ultra-high-speed Aerostatic Motorized Spindle

With the development of the high-density printed circuit board, the number of PCB ultra micro hole showed a trend of rapid growth. Therefore, the speed and accuracy for the PCB drilling machine is becoming more high.the ultra high-speed aerostatic motorized spindle is widely used in PCB drilling which is also as the core of the PCB drilling machine components. The hydrostatic bearing has advantages of high precision, high limiting speed, long life, small vibration and so on. Which is appropriate for the bearing components of ultra high-speed motorized spindle. However, Due to the characteristics of the compressibility and low viscosity for gas, The ultra high-speed aerostatic motorized spindle has the disadvantages of low loading capacity, low stiffness. which make a great contribution to the instability of the ultra high-speed aerostatic motorized spindle. So the dynamic characteristics of the spindle is critical for the performance of spindle when processing.It is desirable to grasp the design procedures of ultra high-speed aerostatic motorized spindle by studying the static performance of aerostatic bearing, hydrodynamic effect, the supporting structure optimization of spindle system.the dynamic characteristics of the motorized spindle. The main research of this article includes the following aspects:1、On the basis of in-depth analyses of gas-lubricated theories,Establishing Reynolds equation and combining with the ANSYS finite element analysis software for numerical calculation and observing figure to devise the pressure distribution of gas film and capacity; What’s more, it is capable of devising the influence of air supplying pressure and structure parameters on the static performance of aerostatic bearing, Then to optimize their structure parameters by considering stiffness,gas consumption,loading capacity and so on.2、By using the method of finite volume software fluent,The bearing in state of rotation are analyzed. Studying the influence of the hydrodynamic effect on the loading capacity.The results show that the hydrodynamic effect of aerostatic radial bearing will increase with the rotational speed improved.3、With the help of the FEA software ANSYS,three-dimensional model of the Ultra-high-speed Micro-cutting Aerostatic motorized spindle based on different support structure was set up. Finite element analysis method of fluid-structure interaction was applied for the analysis of different kinds of structural designs of spindle. The load-bearing characteristics was analyzed and compared in order to obtain Optimized support structure of motorized spindle. It is found that the front bearing structure has the greatest effect in the bearing ability of the motorized spindle bearing, the setting of spindle span contribute a little to the bearing ability, in order to strengthen the spindle rigidity, we can choose the spindle supporting structure of front bearing with muti-hole.4、Modal analysis is carried out on electro-spindle system to obtain the inherent frequency and vibration mode, harmonic response analysis concludes the dynamic change of the displacement of the spindle front end under the external exciting force, which is reference basis for the practical operation and the processing of motorized spindle.