Uniaxial tester improves powder test repeatability
uniaxial powder tester to the FT4 Powder Rheometer
Freeman Technology has added a uniaxial powder tester to the FT4 Powder Rheometer, extending its ability to measure properties that directly correlate with a powder's in-process behaviour.
Uniaxial testing, which involves measuring the force needed to break or fracture a column of consolidated powder, complements the FT4's existing test methodologies for shear, bulk and dynamic powder measurement.
It is a simple and direct method of measuring unconfined yield strength, a parameter related to cohesivity.
Use of this technique in the past has been inhibited by the difficulties inherent in repeatably producing a uniformly packed and consolidated powder column for testing.
As a result, unconfined yield strength data are routinely derived from shear testing, a practical but less direct alternative.
Now, however, Freeman Technology has developed an accessory that, in combination with a well-defined consolidation methodology, produces a homogeneous, uniform powder column for testing.
Measuring the normal stress required to fracture the column directly identifies the unconfined yield strength.
Comparative tests show that the new solution produces data closely comparable to those derived from shear test data but offers improved repeatability.
Uniaxial testing is not suitable for powders with very low cohesive strength, but is a quick and intuitive method for measuring unconfined yield strength of more cohesive materials.
It complements rotational shear testing which in contrast requires less sample, can be used for less cohesive materials and is essential for measuring wall friction data in support of material of construction choice.
Researchers at the RCPE (Research Center Pharmaceutical Engineering) in Graz, Austria, are using the FT4 Powder Rheometer from Freeman Technology to model powder behaviours.
Freeman will be presenting a poster 'The characterisation of granulation wet masses using powder rheometry', at the International Granulation Conference in Lausanne, Switzerland, on 20-22 June.
New software for Freeman Technology's FT4 Powder Rheometer offers a redesigned graphical user interface that improves the display of real-time test information.
At Bulk Solids India 2011, held 6-9 April in Mumbai, Freeman Technology's director of operations will deliver two presentations on the use of automated instrumentation in powder characterisation.
The new graphical user interface (GUI) for Freeman Technology's FT4 Powder Rheometer will be on show at Interphex 2011 on 29-31 March 2011 in New York.