Size distribution is typically of strong interest. However, because the abrasive grains are not spherical, a singular Size measurement is not enough. Particle morphology measurements, comprising both Length and Width, is thus required. Particle morphology bears strongly on abrasive effectiveness. A polygon morphology characterized by sharp angles is the optimal performer.

For size calculation, the elliptical methodology is the most effective model. Although the particles are not elliptical, an ellipse can be fitted, which will yield an effective measurement of Length, Width and Aspect ratio. In this case, the least bounding ellipse (BE) is utilized. For morphology, the polygon model is implemented, as most particles possess a polygonal appearance, with straight sides.

The quantity of fitted polygon sides is measured as Polygon order, and the Polygon angles category describes the interior angles of the polygon. Convexity indicates the degree to which a particle embodies a convex morphology, in other words how well it matches the fitted polygon. A particle characterized by indented sides would embody a lower convexity than one which filled the majority of the polygon.

Image analysis settings with the Pi Sentinel PRO comprised minimum pixel area: 5; maximum pixel area: 50000; binary threshold: 80%; focus rejection parameter: 50; pump speed: 40%, and the option to adjust dimensions for diffraction effects was allowed.

Results

Sample 1

Approximately speaking, Length and Width (BE Width – BE Length) are typically distributed with every Aspect Ratio (Ellipse AR) under 2.

Convexity has a spread to its distribution but is fairly high. Circularity exhibits a spike at 1 as a result of the occurrence of the spheres.

Quantity of sides (Polygon order) averages between 7 and 8. Interior angles (Polygon angles) are distributed around 135 degrees.

Utilizing the post-processing filter, the capacity for reanalysis of the particles, without the spheres, is enabled, by imposing an upper limit of 0.99 on circularity.

The data exhibits only minimal change, since the spheres comprise under 10% of the sample (1430 out of 15114).

Sample 2

In the second sample, the Bounding ellipse width (BE Width) average increased to 28.7 microns, compared to 17.0 in the first sample. Bounding ellipse length (BE Length) likewise grew from 23.9 to 49.4. For these larger abrasives, both Circularity and Smoothness are smaller than the fine particles constituting the first sample.

Polygon order is roughly the same in this instance. Polygon angles exhibit a comparable average, but the histogram now describes a typical skewed normal distribution. A high quantity of the particles in the first sample is too fine to calculate angularity. The larger abrasives possess a higher convexity.

A third sample was generated from the first and second samples for demonstration reasons. Examination of the third mixture reveals the occurrence of the two original materials, in disparate quantities. It is possible to isolate the two components with the use of one of the Particle Insight separation techniques and correlate the results with the initial samples.