SM-111 | CAPPILARY RHEOMETER

Mechanical Structure

• Motor over-current trip
• Emergency stop switch
• Fume extraction
• 89/392/EEC & 91/368/EEC - machinery safety accreditation

• More commonly, zero-length dies are used to directly measure the inlet pressure drop and measure the extensional viscosity using the Cogswell method.
• The twin-bore technique gives obvious experimental advantages including improved throughput since both experiments are preheated simultaneously. Alternatively, the software can be configured to run a two-material test which allows the measurement of the viscosity of two different materials simultaneously.

Working principle

• Material is heated in the barrel to the test temperature.
• The piston pushes the material out of the barrel with a preset speed. (shear rate) And we measure the pressure of the molten material in the barrel with the pressure transducer.
• The pressure increases and gets to equilibrium. The pressure value at the equilibrium of the piston at that speed.
• Then the speed changes to the next preset value and measure the pressure value at that speed.

• By piston’s area and speed, you get a flow rate Q.
• You measure the pressure.
• Shear viscosity is shear stress divided by shear rate.

Software

Basic analysis

• Calculation of shear and extensional viscosity
• Calculation of power law index (n)
• Bagley and Rabinowitsch correction
• Non-Newtonian index
• Carreau, Cross, power law and polynomial curve fits

Derived curves

• Shear rate, melt volume, volumetric flow rate
• Facility to use data from the standard channels (force, pressure, temperature), or user-provided measurement channels to derive further curves
• A powerful set of functions is provided to allow user-defined calculations to be made on the captured data

Test types

• Shear rate sequence – twin bore
• Shear rate sequence – single bore
• Thermal degradation tests
• Pressure vs volume test

Rheometer control

• Manual crosshead control
• Temperature zone control
• Pre-condition sample (thermal stabilization and compression)
• Run pre-defined test
• Purge barrel contents

Die Database

• Database of available dies
• Support for capillary, orifice, and rectangular slot dies

Test information

• Test progress bar
• Real-time graphs of pressures, speed, and position
• Real-time calculation and graphing of rheological properties

Pressure equilibrium

• Automatic and manual

Units

• The software allows you to work in whatever units you choose – it provides by default SI, cgs and US units
• All numeric quantities (measured data and documentation information) are recorded along with their units, and when results are calculated their resulting units are calculated too, ensuring consistency and greatly reducing the potential for errors.

Documentation

• Two types of documentation information are saved along with the test data:
• automatically recorded documentation (transducer and die information for example), and user-entered documentation.
• Documentation fields are configurable depending on your particular requirements, and fields can be made mandatory to ensure that critical information is recorded for every test.

Graphs

• Graphs are used for displaying measured and calculated data. Multiple tests and multiple quantities may be displayed on the same graph.
• Highly configurable appearance including colours, automatic or manual axis scaling, linear or logarithmic scaling, and user-defined or labelling.

Tables

• Tables are used to display calculated results or documentation information.
• The results from multiple tests may be displayed in the same table.
• Flexible formatting includes colours, fonts, column headings, units, and the format of numeric results.

Data export

• Data can be exported to Microsoft Excel in native file format. There is also the facility to export data in CSV (comma-separated values) format, compatible with almost all numeric analysis packages.

Test database

• Test data may be saved either in individual files or in a test database (Microsoft Access format). Multiple databases may be created, for different users or different applications. Test data stored in files may be copied into the database and vice versa. A powerful search tool can be used to interrogate the database and find tests that match particular criteria: for example, by the date of the test, the type of sample, a shear viscosity falling outside specified limits, or a test performed at a particular temperature.

Auto-save

• An auto-save facility ensures that data from a test is never lost, and also imposes a consistent naming scheme for data files. Data can be automatically saved to files or to the test database.

User levels

• The software provides password-protected user levels. The software functions available to each level may be defined, preventing access to sensitive operations that might affect the accuracy of the data.

Saving settings

• Entire software configurations, or partial configurations, may be saved and later restored. This facility is useful both as a backup mechanism and also to allow quick switching between different test types (for example, single bore and twin bore).

Constant Shear and Extensional Tests

Constant Shear and Extensional Tests

Melt Fracture/Flow Instability