How Does a Melt Flow Index Tester Measure the Flow Properties of Thermoplastics?

A higher applied load can generally increase the amount of polymer flowing through the die, while a lower load may produce a different flow rate.

This is why the load used during testing must be selected according to the applicable test method and material requirements.

Manufacturers should always ensure that the same specified load is used when comparing samples under the same test procedure.

Importance of Sample Preparation

Reliable testing does not depend only on the instrument. Proper sample preparation is equally important.

Thermoplastic materials may contain moisture, contaminants, additives, or other factors that can influence their behaviour during testing. If the sample is not prepared according to the applicable procedure, the resulting MFI value may not accurately represent the material.

The sample quantity, conditioning, drying requirements, and handling procedure should therefore be controlled according to the relevant testing method.

Consistent sample preparation helps improve repeatability and makes it easier to identify genuine differences between material batches.

What Can MFI Testing Tell Manufacturers?

MFI testing provides useful information about the processing characteristics of thermoplastic materials.

One of its main benefits is quality consistency. Manufacturers can test incoming polymer batches and compare the results with their established specifications.

If the MFI value suddenly changes from the expected range, it may indicate that the material should be investigated before being used in production.