Confined and Unconfined Powder Flow
Two types of powder flow pattern are typically employed for quantifying flowability: -
Forced (or confined) Flow
A measure of the powder’s flowability when forced to flow, such as through a screw feeder or in an active feed frame.
This property is defined as the
Low Stress (unconfined) Flow
A measure of the powder’s flowability when unconfined, such as during low stress filling, or low shear blending. This property is defined as the
The regimes of confined and unconfined flow are very different and so it is important, when correlating data with process performance, to identify which regime is most representative of the process being considered.