DHR/AR Rheometer: Configuring a New Geometry
The Geometry Wizard is used to configure and define the parameters for each geometry used with the instrument. You will need to create a geometry file for each measuring system (geometry/environmental control system) you have, before using it to run an experiment. You can also create separate files for the same measuring system if, for instance, you want to apply different gap values or other settings to the same geometry. Note that only a single instance of a DHR or AR-G2 Smart Swap™ geometry is allowed.
- NOTE: Parameters that are chosen will vary based upon the selected geometry type. Follow the instructions on the Wizard for your geometry.
Follow the steps below to configure a new geometry:
- Unless you plan to carry out the geometry calibrations immediately following the geometry setup, or you have an DHR/AR-G2 with Smart Swap enabled, it is not necessary to attach the geometry. For a DHR/AR-G2 with Smart Swap enabled, the geometry ID is read when the geometry is attached. If the ID is not in the Smart Swap database, the new geometry wizard starts automatically.
- Select Home > Geometry toolbar > New (geometry). Click Next to proceed. The Geometry Wizard appears, listing appropriate geometries for the currently installed temperature system.
- Select the Geometry type and click Next. If your geometry is not listed, click the Show all geometries checkbox.
- Follow the prompts and enter the geometry information. For example, when setting up a cone and plate geometry, you will need to enter the cone diameter, cone angle, and cone truncation. Click Next to proceed. Note that the Loading gap is the gap that the head moves to when the Raise to Loading Gap icon on the Gap Control panel is pressed. Enter a value that provides enough space for sample loading.
- Enter the geometry constants, if desired, then click to Next proceed.
- The gap temperature compensation value (if appropriate for your geometry) may be determined experimentally. Alternatively, use a nominal value. See Gap Temperature Compensation calibration. Select the checkbox if you want the compensation to be active during temperature changes. Whenever possible, the head position will change to maintain the initial gap. When this is not possible, for example during axial force control where a head movement would exceed the specified limits, a software correction is made to the gap point value stored in the results file.
- A compliance value appropriate for the geometry/rheometer/temperature system combination is automatically entered by the software. It is not recommended that this be modified unless better information is available. Modify the geometry Name if desired, and record any additional information in the Notes section. Click Next to proceed. The name given here becomes the displayed name within the Geometries section of File Manager. The geometry setup is complete.
- Click Finish. The new geometry is created and added to the Geometries section of File Manager. The geometry will also appear as an available geometry through the Geometry toolbar on the ribbon.
- If the geometry is attached, the geometry-specific calibrations may be performed at this point. See Calibrating a Geometry for the DHR or AR Rheometer.
- Repeat this procedure for each measuring system combination.
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