Powder Flow Function: Retain the Consolidation Basis

A shear-test flow function describes strength under a defined stress history. It does not replace every powder-handling test.

Read Strength with Its Stress History

Freeman Technology describes shear-cell testing as a means to assess powder shear strength, unconfined yield strength and flow function. These measurements concern a consolidated powder state and can support an appropriate hopper-design exercise.

Retain the consolidation stress, sample preparation and method beside the result. A powder can be assessed under more than one stress condition. One summary should not be described as covering every hopper depth, storage history or dynamic feeding state. Primary characterization reference.

Illustrative Ratio

Using a declared flow-function ratio σ1/σc, invented values of major consolidation stress 10 kPa and unconfined yield strength 2 kPa give a ratio of 5. The calculation is illustrative and provides no HM powder result or accepted hopper dimension.

The ratio depends on the quantities obtained through the test and analysis. Do not substitute an unrelated force or stress merely because its units match. A complete result should preserve the underlying method and the conditions represented by the pair.

Connect the Test to the Design Question

Ask the designer whether the concern is static discharge, consolidated strength or another material behaviour. Shear and wall-friction evidence can be relevant to hopper design, while a dosing operation may need additional dynamic or representative equipment assessment.

Complete the worksheet with the stress basis, analysis output and specific application conclusion. This gives an auger-equipment discussion more meaningful material evidence without turning a laboratory ratio into a universal promise of flow, output or dose consistency. HM equipment context: Auger Powder Filling Machine.