A
flowability
method is created by selecting the time
and rate of rotation based on evaluated
process conditions.
A
125cc of powder is placed inside of the
measurement drum. The instrument is run
for a set number of avalanches or data
points. The instrument calculates the
power of each avalanche as seen in *Figure
A.*
The
user can create a
flowability
method link where multiple
methods will run consecutively on the same
sample.
This method link allows the user to
measure any changes in the powder as a result
of rotation speed.

The
REVOLUTION Powder Analyzer calculates the
power average by measuring the
change in the power of the powder for each
avalanche. The *power spectrum* shows
graphically the total power amplitude at
each avalanche frequency in *Figure B*.

A
spectrum analysis is also performed by Fast Fourier
Transform (FFT). The FFT power average is calculated as the
square root of the sum of the squares of the
coefficients of the sine and cosine
components.

The
cumulative powder spectra
provides an excellent tool for comparing the
flowability of different powders (*Figure C*). The lower the
avalanche time and power, the better the powder
flows. This analysis allows the
user to evaluate the power and frequency of
their powder's avalanches.

One can
evaluate the powder's power changes over
time by reviewing the surface slope. The surface slope indicates if the
powder avalanche size has
changed over time. The
REVOLUTION Powder Analyzer also measures
avalanche angle and rest angle of each avalanche.
This Angle Graph displayed in *Figure D * will indicate the average angle
required to start and continue the flow of
the powder. For example, let's say the
powder has to flow freely and smoothly from
a small container. The Angle Graph will determine the required average
angle to start and maintain
the flow of the powder.

In addition to avalanches,
the REVOLUTION Powder Analyzer measures many additional
parameters to help determine the differences between
powders and establish parameters for predicting
powder flowability performance. These measurements include fractal
dimension (*Figure E*),
powder volume (*Figure F*) and surface linearity.