An Ultra-High Speed Spindle for Micro-Milling

该项目的研究目标是研究目标转速在750,000 rpm至1,000,000 rpm且具有亚微米径向误差运动的微细磨削主轴的轴承和驱动技术；以及能够在这些高频下测量切削力的力测力仪的新概念。实现这些目标的方法将是开发挠性枢轴可倾瓦流体动力轴承和空气涡轮驱动器的分析和计算模型，适用于转速非常小的轴直径，使切向表面速度接近马赫1。所使用的方法将使用刀体本身作为主轴，一端有一个整体的空气涡轮。高频力测力仪将采用一种新的叠层弯曲设计，其动力学可调以在感兴趣的频率范围内提供平坦的响应。将开发叠层弯曲系统的分析和计算模型来指导设计，并将使用实验研究来验证模型的准确性。如果成功，这项研究的好处将包括提高有效地利用球磨作为制造微尺度和中尺度器件的过程的能力。此外，用于研究微细磨削机理的新工具将有助于加强对该过程的科学理解。这将为微系统设计者带来新的设备类别和更广泛的材料范围。这项研究也将有助于培养一支受过先进制造技术培训的劳动力队伍。

The research objectives of this project are to investigate bearing and drive technologies for micro-milling spindles with target rotational speeds in the range of 750,000 rpm to 1,000,000 rpm and having sub-micrometer radial error motion; and new concepts for force dynamometers capable of measuring cutting forces at these high frequencies. The approach to accomplishing these objectives will be to develop analytical and computational models of flexure-pivot tilting pad hydrodynamic bearings and air-turbine drives for very small shaft diameters with rotational speeds that produce tangential surface speeds approaching Mach 1. The approach used will be to use the tool body itself as the spindle shaft with an integral air-turbine on one end. A high-frequency force dynamometer will be constructed using a novel stacked flexure design with dynamics tuned to give a flat response in the frequency range of interest. Analytical and computational models of stacked flexure systems will be developed to guide the design; and experimental studies will be used to verify the model accuracy.If successful, the benefits of this research will include improved ability to efficiently utilize milling as a process for fabrication of micro-scale and meso-scale devices. Additionally, new tools for studying the mechanics of micro-milling will allow for enhanced scientific understanding of the process. This will result in new classes of devices and a broadened material range for designers of micro-systems. This research will also contribute to the development of a workforce trained in advanced manufacturing technology.