Melt flow tester can be simply explained as a process of measuring the flow of a polymer, after it gets melted. The outcome of this melt flow tester is better known as mass-flow rate (MFR) or melt volume-flow rate (MVR). In this process, a portion of mass or volume of polymer flows through a considerable die that is conditioned in specific temperature and pressure. This process may sound complicated, but it is quite easy.
Here, a small quantity of thermoplastic sample in granule or flake form is first heated in a barrel. Remember, the temperature is preset to melt the polymer into a viscous liquid. This is next, pushed through a capillary die by a piston that is full of dead weights. Once the small amount is extracted from the die, it is then removed, and weighed. The resulting volume of the material is then measured by machine.
What is the Standard Melt Flow Tester?
Usually the standard melt flow tests used is ASTM D1238 and ISO 1133. It also comes with a distinct equipment specification and test methods. There are different material types available in the market, we have to measure the temperature and weights for the melt flow. The mass -flow rate (MFR) or melt volume-flow rate (MVR) results, comes with the test parameters. Another important fact is MFR/MVR of a polymer is inversely proportional to the molecular weight. Melt flow tester is used for quality control in manufacturing facility or process control laboratories.
Melt flow is related to the molecular weight. High melt flow means low molecular weight. Apart from that, you need to use a melt flow tester to measure the material’s melt to flow under a certain pressure. You can also measure the rate of velocity of a material by this tester.
The Direct Outcome of Melt Flow Testing:
- The entrance materials is quality checked
- It is a typical index value that verifies the in-house material
- It acts as an evaluation tool for various new material suppliers
- Another benefit of this test to compare new materials in product development setting
- It facilitates comparison of batches of materials in a short time
- It measures the approximate flow properties used in extrusion processes
- It can also help in predicting the different polymer processing techniques
The Significance of the Test:
Understanding the key principles of the test is vital to determine its importance in manufacturing facility. As per the principle of the testing, the load suggests the input that is used to steer the material through its orifice. The term flow rate implies the output. The MFR test can be explained as a constant shear stress test that has a pressure restricted configuration. It varies greatly from a capillary rheometer.
If you are unsure about the usage of a rheometer, then you need to know this device helps in measuring the viscosity. This viscosity enables the regulation and the alteration of the flow rate of the test. You need to acquire the flow rate while measuring the force. This is the basic principle that you need to keep in mind to comprehend the capillary rheometry that controls shear rate test. This enables in attaining the exact measurement of viscosity or resistance to flow.
Conclusion
Thus, melt flow testing is the ideal method to measure the flow rate of the polymer for good. The temperature and weight load is specially selected to execute the process. In this article, we have tried to throw light on the essential aspects that you need to learn about melt flow testing for better understanding.
