Abstract
This paper demonstrates for the first time a method for surface modification of a substrate material based on the generation of localized vortices of abrasive slurry using slender oscillating fibers. In experiments presented in this paper, the abrasive slurry is a water based suspension of 1 µm alumina particles. This is pumped onto, and flows across, the specimen surface. A fiber (typically 7 µm in diameter and between 3.5 to 5 mm long) is immersed into this flowing slurry and oscillated at frequencies around 30–40 kHz to produce a small rotational flow (vortex) that results in the locally accelerated particles. Using such a system, it has been possible, over machining times of 6–24 hours, to produced localized depressions in the surface of a silicon substrate with typical depths of around 60–700 nm and widths of around 10–300 µm. Based on these initial studies the material removal rate is estimated to be approximately 40 nm per hour. Using white light interferometry and stylus profilometry the surface deviations (roughness) of these features have a root mean square variation in the region 1–2 nm, which is comparable to that of the surface remote from the machined feature.