An Ultra-High Speed Spindle for Micro-Milling

University Of Florida, Gainesville FL

Investigators

Abstract

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.