Plastic are used on a large scale for industrial production purposes and housewares to fulfill the need for different applications. Plastic is used in almost all production vertical in one or other manner. With the wide usage of plastics in different production vertical, it is necessary for the manufacturers to test the quality of the plastics. One of the major properties of plastics is viscosity. The viscosity of plastics helps to measure the melt flow rate and melting quality of the plastic granules.
During the process of injection molding of plastic resins, manufacturers usually experience that the setting of temperature and other molding condition, specifically in the case of injection pressure, speed and the temperature of molding greatly affects the quality of the plastics. If the temperature and speed are not set appropriately, it will affect the shape and size of the end product. Although there are several methods that are used to evaluate the viscosity or fluidity of plastics, the most convenient and appropriate method for viscosity determination is Melt Flow Index Test. This test helps to measure the melt flow rate, melt flow index of the plastics.
How Melt Flow Rate of Plastic Resins is calculated?
The melt viscosity rate is measured by inserting approximately five grams of plastic resins in the heating barrel of melt flow index tester. After that, the resins are heating up to a level. This makes the melted plastics flow out of a barrel with a specific weight and in a specific amount of time. Both the value of melted plastic weight and time period helps to measure the melt flow rate of the granules. The melt flow index testers that are supplied by reputed manufacturers strictly follows the instruction of standards that are provided by national and international standardization authorities such as ASTM, ISO, BIS, JIS, etc.
Evaluation of Plastic’s Quality
Plastic resins with the high Melt flow index are considered as the material with the best rate of viscosity. The poor flow of resins depicts low rate of MFI. Melt flow rate explains the viscosity of the plastic is static conditions and on the other hand, at real time injection molding process, the plastics are flowed out from a congested gateway which slows down the flow of plastic. Hence, it is necessary for the manufacturers to consider the melt flow rate of plastics for injection molding procedure accordingly.
As stated above, MFI is used as the best measure to calculate the index of the viscosity of plastic granules to analyze the properties of plastics in a simple manner.