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Rheometer

The world’s most successful rheometer series

Rheometer family based on cutting-edge technology: The amazingly versatile MCR rheometer series covers all rheological applications from routine quality control to high-end R&D applications – count on a convenient, highly precise rheometer custom-tailored to your needs.

The MCR rheometer series from Anton Paar offers you one thing first and foremost: An open range of possibilities. Whatever your rheological requirements are and will be in the future – based on its modular setup, your MCR rheometer is efficiently and comfortably adapted to meet your needs.

Benefit from the rheometers’ peak performance in oscillatory as well as rotational tests based on the powerful, dynamic EC motor, the patented normal force sensor integrated in the air bearing and time-saving features for maximum reliability and ease of use.

Build on your rheometer to cover any application need: Simply integrated temperature devices provide unrivaled temperature control from –150 °C up to 1000 °C. You can also easily connect a wide selection of application-specific accessories for rheo-optical investigations, tests with additional parameters such as pressure or a magnetic field – and you can also use your rheometer for extended material characterization such as tribology, DMTA measurement and much more.

Contact us for more information on the MCR rheometer series.

Unrivaled rheological performance in a future-proof modular setup: The MCR rheometer series from Anton Paar.


The EC-Motor Technology of the MCR Rheometer Series

The continously improved synchronous electrically commutated (EC) motor techology is used in MCR rheometers since 1995. Electrical commutation allows the excitation of the motor without brushes or mechanical contact. It is therefore also called brushless DC motor.

The Motor Design

The rotor of the drive (b) is equipped with permanent magnets whereas in the stator (a) the magnetic poles are produced by coils with opposite polarity. The magnets in the rotor and the stator coils attract each other so that a rotating flux of current in the windings of the coil produces a frictionless synchronous movement of the rotor.

 

Rheological Advantages of the EC-Motor

Motor CharacteristicsRheological Advantage
Instantenous build up of the magnetic field, no magnetic inductionFast response times for step rate and step strain tests
No eddy current and no heat
production in the motor
Torque values up to 300 mNm
Linear relationship between electro-magnetic torque and stator currentControl and resolution of smallest speeds deformations and torques
Known and constant magnetic fieldAccurate CSS, CSR and CSD control without overshoot

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Air bearing

The EC motor is supported by a radial air bearing to center and stabilize the shaft and an axial air bearing to hold the weight of the rotating parts. The accuracy, drift stability and rigidity of the air bearing has been significantly improved over the last decade to push back the boundaries of low torque measurements. In addition, the digital signal processing technology introduced in 1995 allows torque mapping, which improves the measurements at lowest torque values.

Normal force sensor (US patent 6,167,752)

The patented normal force sensor inside the air bearing measures the normal force with the help of an electric capacity method. An occurring normal force produces an extremely small deflection in the air bearing which is measured over the changed capacity. This method allows static normal force measurements as used for gap control, in tack or squeeze flow tests but also normal force measurements such as in transient or steady state rheological measurements.

As the sensor is located in the air bearing, normal force measurments are available for all temperature devices and special accessories.

Example

First normal stress coefficient (Ψ1) of a polymer solution (PIB) in a step rate test.

Normal stress coefficient

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Nanorheometry: Nano torque and strain resolution

Nanotechnology has become an important field in material science over the last couple of years. Quite often these materials have unique mechanical properties and their characterization requires a modern rheometer with excellent torque and strain resolution.

The unique EC-powerdrive motor, the high-precision air bearing and TruStrain™ allow to control and resolve extremely low torque and deflection angle values as they are required for nano-structured materials.

 

Example

It is a fact that the torque limit of a rheometer system depends on the measuring conditions and data sampling. The amplitude sweep diagram below proves that the MCR is capable of resolving torque values down to 1 nNm and setting a deflection angle of 10 nrad while still providing good measuring data. These torque and deflection angle values are a decade below the rheometer's specifications of 10 nNm and 100 nrad. We impose these limitations on our instruments because we want to be able to guarantee our specifications at average laboratory conditions even though the rheometer can do better.

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Direct Strain Oscillation (DSO): Real-time position control oscillation

Generally, a strain-controlled oscillation test in a stress-controlled rheometer consists of the following steps: applying one full oscillation cycle with an arbitrary stress amplitude, measuring the strain amplitude, adjusting the stress in the next oscillation cycle, and repeating this routine until the desired strain amplitude is reached.

The Direct Strain Oscillation (DSO) method uses a different approach. It does not require a full oscillation cycle but uses a real-time position control and adjusts to the desired strain directly on the sine wave. Therefore, the actual movement of the measuring system directly follows the required change in strain during each individual oscillation cycle.

DSO is especially valuable for measurements on samples with low viscosity and weak structure such as gels, emulsions, suspensions, colloids, surfactant solutions, lubricating grease, and foams.

Advantages

  • Real strain controlled tests in oscillatory mode
  • Exact strain setting right from the first oscillation cycle, no overshoots in strain
  • Measurements at extremely low angular resolution and low torques
  • Position control of the geometry, no drifts

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Toolmaster™ - Automatic measuring system and accessory recognition

The revolutionary Toolmaster™ (US Patent 7,275,419) represents the first completely automatic tool recognition and configuration system.

All measurement geometries and environmental systems are recognized automatically as soon as they are connected to the rheometer. Transponder chips in the control cabel of the accessory and in the measuring system contain all relevant data and prevent of making selections in the software.

QuickConnect, the user-friendly quick-fiitting coupling, allows one-hand connection of the measuring geometries and ensures fast and convenient changes of the measuring system without screwing.

Benefits

  • No errors due to wrong selections in the software
  • Transfer of all geometry data, e.g. truncation, diameter and cone angle.
  • Unique identification of individual measuring geometries by the transfer of geometry serial number
  • No errors in documentiation and perfect for traceablility  (21CFR Part11)

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TruGap™ - The innovative and patented gap measurement system

Errors in gap dimensions directly influence the accuracy of results in parallel-plate and cone-and-plate measurements. Accurate gap setting is therefore required in order to measure rheological properties accurately.

The TruGap™ control for MCR Rheometers has been developed to avoid gap errors as they can occur in temperature sweep experiments or when doing the zero gap without waiting for thermal expansion of the measuring system. TruGap™ measures the gap directly using a magnetic induction method and adjusts it to the desired position independent of the temperature and thermal expansion.

Benefits

  • No worries about the gap in parallel-plate and cone-and-plate measurements
  • No problems with thermal expansion of measuring geometries
  • No time-consuming calibration of gap compensation factors prior to temperature sweeps
  • Documentation and traceability of the real gap

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