Analytical Method and Experimental Verification of Aerostatic Spindle Design Based on the Coupling Effect of Ultra-precision Grinding

Abstract

摘要:超精密内圆磨床工件轴采用空气静压支承，其在超精密内圆磨削过程中与砂轮轴间的耦合效应往往会改变空气静压主 轴的回转精度并引入新的误差，对加工过程和工件精度有重要影响。提出了一种新的建模方法来研究空气静压主轴回转的耦 合效应及对超精密磨削过程的影响。将工件轴-砂轮轴组成的磨削系统作为一个整体加工闭环系统来进行设计分析。为了科学 地解析这一过程，以开发的超精密内圆磨床为研究对象，建立空气静压主轴双转子耦合模型，评估了空气静压轴承参数和超 精密内圆磨削过程对主轴动态响应的影响。并进一步分析耦合效应在亚微米-纳米尺度下对加工表面形貌的影响。研究发现， 空气静压轴承参数和动态磨削力对主轴振动有很大的影响，会降低表面加工质量，而最终的加工表面形貌由磨削系统和磨削 过程的耦合共同影响决定。研究最后展示了加工试验验证，用频谱分析方法得到了加工表面的圆度误差，试验与分析结果一 致，进一步验证了该方法的精密工程可靠性和应用性，该研究对于设计分析高精度空气静压主轴与科学的理解超精密内圆磨 削系统中空气静压主轴耦合效应具有重要意义。

The utilization of aerostatic spindles in various applications is accompanied by the presence of coupling effects at the spindles and the machining system during the machining process. These coupling effects inherently result in a decrease in the spindle rotational motion accuracy, subsequently introducing additional errors significantly influencing both the machining process and the precision of the workpiece. The phenomenon of coupling in ultra-precision internal grinding might result in alterations to the rotary precision of the aerostatic spindle. This research presents a novel modeling approach for investigating the coupling effects of the aerostatic spindle rotary and its impact on the grinding process. The comprehensive analysis of the grinding system, which includes the workpiece spindle and the grinding wheel spindle, is conducted. The research investigates the utilization of the developed ultra-precision internal grinding machine to provide a comprehensive explanation of the process. To assess the impact of the aerostatic bearing parameters and the grinding process on the dynamic response of the spindle, a double-rotor coupling model is established. Furthermore, an analysis is conducted to examine the impact of the coupling effect on the surface topography at the submicron scale. The influence of bearing settings and dynamic grinding force on spindle vibration, which can lead to a degradation in machining quality, has been observed. Additionally, the final surface topography is defined through the coupling effects of the grinding system and the grinding process. The study concluded with the execution of machining experiments, wherein the roundness error of the machined surface was determined using spectral analysis. The obtained results from both the experimental and analytical approaches exhibited consistency, thereby confirming the reliability of the employed method. This research holds substantial importance in the realm of high-precision aerostatic spindles design and provides valuable insights into the coupling effects between the workpiece spindles and wheel spindles within the grinding system.