The three sizes of Freeman Technology Shear Cell modules for the FT4 Powder Rheometer allow the shear properties of powders to be measured. Using a shear cell on the high-specification FT4 platform allows the automatic generation of accurate and reproducible shear information which complements the dynamic flow date.
Freeman shear cells
The FT4’s high-specification hardware platform combined with the precise control and extensive analysis capabilities of its software, have allowed the design of a highly sensitive, reproducible and fully automated shear measurement system. Shear strength in both consolidated and unconsolidated samples can be measured.
The Freeman shear cells offer:
- Fast, automated operation
- Independence from the operator
- High reproducibility
- Sample conditioning before test
- Three sizes of shear cells - 85ml, 10ml and 1ml sample size
- Testing of unconsolidated powder
- Small sample volume - down to 1ml
- Sophisticated data analysis
- Comprehensive data plotting and formatting
- Force control and position control modes available
- Precision measurement of axial and rotational position
- Hopper design methodology and software
Fully automated testing
The Freeman shear cell accessory is delivered with a library of testing programs. To perform a test the user simply selects the required program, loads and prepares the sample and then clicks 'run'.
The following stages are fully automated:
- The standard Freeman conditioning cycle prepares the sample for testing
- In a 'pre-shear' stage, the powder bed is sheared in order to maximise the major principal stress
- For powder characterisation, a single series of tests at a particular pre-consolidation stress may be sufficient. For example, a powder may be pre-consolidated to 9kPa and then sheared at 7, 6, 5,4 and 3kPa with pre-consolidation to 9kPa between each test
- More comprehensive, multi-stage testing to produce a range of yield loci corresponding to different pre-consolidation stress levels. Usually a given sample will be suitable for repeated shear testing to obtain the required set of yield loci. In this case the entire evaluation is automated.