Brown, Christopher A.
One commonly used abrasive grit in making grinding wheels is cubic boron nitride (cBN). It is the goal of this project to study the surfaces of individual grits to determine if there is a relationship between surface character and grinding performance. The surfaces of four types of cBN are studied using a confocal microscope, and the measured surface is analyzed using a fractal method. These results are compared to those from a single grit grinding evaluation test to identify possible correlations. The grit with the highest relative areas is the microcrystalline grit, followed by the multi-crystalline grit, the second single crystal grit, and the first single crystal grit, with some overlap among the two single grits especially. These results seem to correlate with the performance as far as fracture forces, but the relative area does not seem to directly relate to grit wear. The two grits most different in structure, single grit #1 and the microcrystalline grit, are easily differentiable by relative areas at scales of observation of approximately 100 um? and lower. The second single crystal grit is surprising[ly] not differentiable from the microcrystalline grit, although this is most likely due to two outliers, which are measurements on the same facet, that have much higher relative areas than the rest of the single crystal grits, and thus expand the range, perhaps inaccurately. The multi-crystalline grit is differentiable from the microcrystalline grit, but only at very fine scales. The two single crystal grits and the multi-crystalline grit are not differentiable from each other, thus making correlation to performance difficult at best.
Worcester Polytechnic Institute
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