DEVELOPMENT OF EXPERIMENTAL FACILITIES FOR INVESTIGATIONS OF VORTEX MACHINING

Abstract

This dissertation presents work done in investigation of a novel polishing process called Vortex Machining. Vortex Machining uses an oscillating probe to induce vortices in a polishing slurry above a workpiece, thereby removing material in regions measuring micrometers laterally. The probe features a high-aspect ratio geometry that enables it to reach into (and potentially polish) complex geometries such as small holes and deep channels. The probe can also be used for force and displacement feedback, providing potential for in situ measurement. Throughout this research two test facilities have been developed; a low-power facility utilizing a 7 ?m diameter probe oscillating at 32.7 kHz with amplitudes in the tens of micrometers, and a high-power facility utilizing a 500 µm diameter probe oscillating at several kHz with amplitudes of several hundred micrometers. The facilities control probe position to 0.5 µm, slurry depth to 10 µm, and probe phase to 2.5°; and have demonstrated machining capabilities used in preliminary studies of the process. Analysis software was developed to characterize process footprints. While substantial variability in footprints is observed, material removal rates of the order 10-8 and 10-4 mm3·hr-1 have been measured on silicon. Surface finish values of footprints are typically sub-nanometer and thus comparable to traditional polishing

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