Melt Flow Testing Basics

Melt Flow Testing Basics

Melt Flow Indexers


Melt Flow Rate is simply the measure of the ease of flow of melted polymers. Small pellets of a material are melted at a controlled temperature and an applied load pushes the sample through a die of specified size. The melt mass-flow rate is the amount of material extruded in 10 minutes, reported in g/10 min.


Melt mass-flow rate (MFR) and melt volume-flow rate (MVR) are typically used in quality control and production control environments as a quick and easy-to-measure index. Though a simple test, melt flow characteristics can be an important part of many quality control and R&D environments in order to:

  • Verify incoming/entrance material
  • Regularly perform a quality control check of a material
  • Compare new materials in a product development setting
  • Perform evaluations for new material suppliers
  • Quickly compare batches of material
  • Predict how a polymer will behave in a number of processing techniques

Learn more

Through our webinar recording, receive a deeper explanation on the fundamentals of melt flow testing.

Interested in a Melt Flow Indexer?

Contact Us


Critical measurements require instrumentation you can trust. Instron’s Melt Flow Range covers all methods of the most common ISO and ASTM melt flow testing standards and are suitable for a wide range of polymers. Systems are configurable with features that can help increase productivity in a busy lab, and reduce the chance of injury by decreasing operator interaction with the machine. You can find specific information on our melt flow indexers here.

Melt Flow Indexers