Determination of melt mass flow rate (MFR) and melt volume flow rate (MVR) according to ISO 1133, ASTM D 1238

Extrusion plastometers provide standard values for the melt index (MFR) and volume index (MVR) of filled and unfilled thermoplastics to ISO 1133, ASTM D 1238 and other similar standards.

Zwick produces straightforward extrusion plastometers for Method A, together with instruments which feature automatic displacement measurement and can be used for measurements to Methods A and B.

Cflow extrusion plastometer

Method A (according to ISO 1133)

The Cflow extrusion plastometer consists of an extrusion barrel which is heated exactly to a pre-set temperature, a die of standardized diameter and a piston with a weight applied to its upper end. The material to be tested is loaded into the extrusion barrel; after a specified pre-heating period it is extruded through the die by the force of the weight acting on the piston. The extrudate is cut off at constant time-intervals and weighed. The result is the melt mass flow rate according to ISO 1133 (MFR), which is calculated from the extruded mass per 10 minutes.

This method is suitable for individual tests with lower specimen quantities.

Aflow extrusion Plastometer

Method B (according to ISO 1133)

This method requires the extrusion plastometer to be equipped with a displacement transducer which measures piston travel during the test. The melt volume flow rate (MVR) is the extruded volume per 10 minutes.

This method is often used in production checks as it is more suitable for automation and simpler in operation, mainly because no weight determination is necessary for the individual extrudate cuts. Provided the density of the melt is known, the MFR value can be calculated; connecting a balance to the instrument enables melt density to be determined also.

In some cases it can be of interest to know the ratio between flow rates determined under different piston loadings. This value is known as ‘Flow Rate Ratio’ (FRR).

Zwick 4106 plastometers can be equipped with an automatic load-change unit. For lower MVR values this allows tests from one barrel-loading at different weight steps, saving time compared with individual measurements.

The weight steps can be programmed in an ascending, descending or mixed sequence. The test sequence can be time-controlled or displacement-controlled for each measurement step, giving the operator maximum freedom in the arrangement and optimization of test methods.

Typical products for this application

Aflow melt index tester 

Aflow extrusion plastometer

The Aflow extrusion plastometer (melt index tester) was developed especially for laboratories with high testing volumes, as reflected in its robust design and convenient operation.


Cflow melt index tester 

Cflow extrusion plastometers

The easy-to-use Cflow extrusion plastometers (melt index testers) are designed as a stand-alone instrument. They are specifically intended for MFR determination and are suitable for goods inwards checks.


Mflow melt index tester 

Mflow extrusion plastometers

The basic version of the Mflow extrusion plastometers (melt index testers) can be used to determine the melt mass flow rate (MFR).




Zwick Aflow Extrusion Plastometer - Fließprüfgerät

Aflow Extrusion Plastometer to Determination of the melt mass-flow rate (MFR) and the melt volume-flow rate ...
Video 00:04:43
47_Zwick_Aflow_Extrusion_Plastometer_-_Fliesspru__fgera__t.wmv (32 M)

Zwick Mflow Extrusion Plastometer - Fließprüfgerät

Mflow Extrusion Plastometer to Determination of the melt mass-flow rate (MFR) and the melt volume-flow rate ...
Video 00:03:33
46_Zwick_Mflow_Extrusion_Plastometer_-_Fliesspru__fgera__t.wmv (19.4 M)


Zwick USA
Tel.  +1 770 420 6555
E-Mail  info@zwickusa.com


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