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[May 2005]
Reference Material Tests Validate Measurements
Freeman Technology (Malvern, Worcs, England) recently introduced a fully automated shear cell accessory for use on its FT4 Powder Rheometer. Now, work performed by an independent laboratory using BCR reference material CRM-116 (Community Bureau of Reference: BCR, Belgium) has confirmed the new shear cell's ability to perform verifiable and highly repeatable shear tests.
This reference material has been developed to allow verification of shear tests and experimental technique. As part of its overall evaluation of the FT4, researchers at the LGPSD-CNRS laboratory at the Ecole des Mines d'Albi in France have been working in conjunction with Freeman Technology's Powder Applications Laboratory in the UK. Results from the work showed that measurements made on CRM-116 using the FT4 shear cell gave excellent agreement with shear parameters specified for the standard.
The FT4 is a universal powder rheometer that is used to conduct an array of powder flowability tests that provide a means to characterise the flow properties of powder materials and relate these to performance in process. Where shear testing is required to complement flowability data, the new automated shear cell accessory is said to offer significant advantages over conventional methods.
Shear testing using the FT4 is fully automated, minimising operator involvement for greater repeatability and reproducibility of results. It is said to be fast, with tests completed in around 40 minutes. Measurements can be made at low levels of material compaction, thanks to the system's high sensitivity and over a wide range of stresses up to 23 kPa, allowing simulation of many different packing conditions. Conditioning of material before testing ensures homogeneity and a high degree of repeatability. As little as 35ml of material is needed to perform the measurement.
The shear test involves simply selecting a test programme, preparing the sample, then starting the fully automated test sequence. The shear cell uses the FT4 powder rheometer's ability to control force, the rate of application of force and strain rate as part of the automated shear test.
www.freemantech.co.uk
ENDS