The research objective of this award is to obtain an understanding of a new, nanometer level, surface removal process that utilizes locally induced vortices of polishing slurry. These vortices are produced by a micrometer scale oscillating fiber immersed in the fluid near to the surface to be machined, the vortices being stationary relative to the probe. Probes of varied diameters (7 µm to 400 µm), oscillating at high frequencies (over 100 Hz to 10?s of kHz) will produce localized vortices of varying size and magnitude resulting in material removal footprints with lateral dimensions of less than a millimeter. The size of the process footprint will be controlled by the amplitude and frequency of the driving oscillations and the orientation of the probe with respect to the workpiece. An analytical model will be used to isolate the fiber sizes and drive frequencies required to produce differing vortex patterns and velocity profiles. An in-house experimental set-up will enable correlations between the predicted vortex dynamics and the actual process material removal footprints. Actual mechanisms (process parameters and slurry composition) contributing to material removal rates and surface quality will also be investigated.
If successful this project will realize a relatively low cost technology with the following features and capabilities; 1) sub millimeter sized tooling of controllable size, 3) the ability to remove material from highly localized regions without imparting damage into the workpiece, 4) the ability to finish traditionally challenging geometries such as micro fluidic channels and re-entrant features, and 5) the ability to remove mid spatial frequency errors imparted by current subaperture processes that use larger tooling. This will be accompanied by experimental verification of analytical models which will facilitate expedient isolation of optimal process parameters. The undergraduate and graduate students involved will gain competency in core technologies relevant to US manufacturing such as micro-manufacturing, precision design, metrology, and chemistry Demonstration modules will be developed to promote science and engineering subjects through summer camp programs and to highlight the interdisciplinary nature of precision engineering in graduate level Mechanical Engineering, Optics and Nanoscale Science programs.
