There are some types of testing devices that are incredibly complicated and are used for a very wide range of testing applications. Other testers are relatively simple in comparison and design but nevertheless equally important in providing precise scientific information to allow developers, designers and manufacturers to choose the most appropriate material for specific types of requirements.
Additionally, some testing, including that conducted through a melt flow index tester can be used for quality control and consistency in products. This is effective to ensure there are no contaminants present or to even determine the specific types of polymers present in a given sample of material.
The Basics
All types of melt flow index tester models will measure how a melted polymer moves under specific conditions. This is done through a melt mass-flow rate or melt volume-flow rate test. It is the amount of the mass (the melt mass-flow rate) or the volume (melt volume-flow rate) that will be moved through a die of a specific known size when under a controlled and known pressure and at a very precise temperature.
Since all polymers will have their own flow rate, by having the knowns of the temperature, pressure and the die size the measurement obtained will allow the technician to determine the polymer or the purity of the polymer.
The test works through a simple process. The polymer is usually flake, pellet or a powder when tested. It is then melted in a barrel of the melt flow index tester that holds a very precise temperature. The polymer is fully melted to a viscous fluid and then the pressure is applied and measured. The machine then measures the flow through the die for volume or the extruded component that has passed through the die for the mass.
The Benefits
With the use of melt flow testing with a very precise machine, it is possible to sample and compare different batches of product to ensure complete uniformity. As these tests are very easy to complete, they are ideal when multiple testing is required. They can also be used to compare different materials to determine which polymer is going to have the properties and characteristics needed for a specific type of application.
Additionally, this type of testing is commonly used for manufacturers and fabricators to compare different suppliers or different options in materials when moving to new types of production options.