How do you test the MFI of plastic products accurately?

How do you test the MFI of plastic products accurately?

The melt flow properties of plastics play a pivotal role in determining their processability and performance, which is why they are rigorously tested. These tests enable manufacturers to evaluate the behaviour of plastic materials during the melting and moulding stages, ensuring that they meet specific industry standards and requirements. Presto melt flow index tester is one of the high-quality lab testing instruments that has been designed to test the melt flow properties of the materials and ensure that materials will be tested under prescribed conditions of temperature, load and piston position in a cylindrical cavity inside a heated metallic tube barrel.

This lab testing equipment has been designed as per industry standards including ASTM D 1238-1992, ISO 1133, IS 2267-1972, IS 2530-1963, IS 10810-1984. It will ensure accuracy in test results. Presto is a leading manufacturer of MFI testers and designs this quality testing equipment at the best and most affordable prices.
In this blog, we are going to discuss brief information about the Presto melt flow index tester and how you can easily test the MFI of plastics by performing an MFI test with the melt flow index tester.

All about melt flow index test on plastics

Plastic products are an integral part of different manufacturing industries. But have you ever wondered how manufacturers ensure the quality and consistency of these plastic products? These materials will be undergone several quality tests that make it easy for the manufacturers to conduct quality tests on the materials.
One of the most common quality tests that will be conducted on the material is the melt flow index test. This test will be carried out on the plastics with the help of specialized lab testing equipment known as a melt flow index tester.
During the MFI test, a specific amount of molten plastic is extruded through a standardized die under controlled conditions. The time it takes for the plastic to flow out of the die is measured, giving us an indication of its melt flow rate.
Presto being Asia’s No.1 manufacturer of lab testing instruments has designed high-quality testing equipment to test the melt flow properties of molten plastics. Now, let us discuss brief information about the Presto melt flow index tester.

Presto Melt Flow Index Tester: Best Lab Testing Instrument for Measuring MFI on Plastics

The Presto Melt Flow Index tester is one of the high-quality testing equipment that can be used to test the flow properties of molten plastics and provide precise and reliable measurements. This deluxe model of this testing instrument is equipped with an automatic sample-cutting mechanism, enabling convenient and consistent sample preparation.
The digital preset timer adds to the accuracy and repeatability of the tests. The die steel barrel of the tester ensures uniform and consistent heating of the barrel and test cylinder, contributing to reliable test results. The corrosion-resistant finish enhances the durability and longevity of the instrument.
This quality testing equipment includes a digital preset timer with a range of up to 999 seconds, which can be adjusted to hours, minutes, and seconds as needed. It has specific dimensions for the piston head, heater tube cavity, and die, ensuring standardized testing conditions.
The weights provided by the tester (1.2 kg, 2.16 kg, 3.8 kg, and 5 kg) allow for different load options during the test. The temperature controller utilizes PID technology, further enhancing temperature control accuracy. This lab testing instrument plays an important role in polymer processing.
Now, let us discuss brief information about the features and technical specifications of this quality testing equipment.

Features of Presto melt flow index tester

  • Microprocessor-based PID controller
  • Automatic sample cutting
  • Digital Preset Timer for accuracy and repeatability
  • Die Steel barrel for uniform and consistent heating of barrel/test cylinder
  • Corrosion resistant finish

Technical specifications of Presto melt flow index tester

  • Display: LED (Digital)
  • Temperature Range: Ambient to 400°C.
  • Accuracy: ± 1°C.
  • Resolution: 0.1°C.
  • Timer: Digital Preset up to 999 seconds (Changeable to Hrs:min: sec)
  • Dimensions of piston head: 9.47mm diameter
  • Diameter of heater tube cavity: 9.55mm ± 0.005mm
  • Dimensions of Die: 2.095mm ± 0.005mm
  • Weights: 1.2 kg; 2.16 kg; 3.8 kg & 5 kg
  • Sensor Type: PT 100
  • Temperature Controller: PID
  • Sample Type: Resins or Plastics
  • Sample Cutting: Automatic motorized
  • Power Supply: Single Phase, 220-240 AC, 50 Hz.
  • Paint: Powder Coated Grey and Blue Combination along with zinc/bright chrome plating.
  • Optional Accessory: Lab Weighing Balance 200gms
  • Standard Accessory: Orifice, Piston, Spoon, Plumb Line, Funnel, Material charger, Mirror, Tweezers, Barrel cleaner, Orifice cleaner, Sample cutter and Accessory stand
With these high-end features and technical specifications, manufacturers can easily perform quality checks of polymers and ensure accuracy in test results.  
Now, let us discuss some easy-to-follow steps for testing the melt flow index test of plastics.

Easy-to-follow steps for testing the melt flow index test of plastics

  • Start the machine by plugging the mains socket of the machine into a 3-pin 15 amp socket.
  • The PID controller will show some readings on the PV & SV. Set the SV value on the PID controller along with test duration timing on the digital timer.
  • After setting the temperature and timer, turn the heater on by pressing the heater switch. Wait for the PV value to reach the value of the SV display.
  • After the required temperature for the test has been attained, fill the barrel of the machine with the plastic granules you want to test. Poke the granules with the plunger after they are inserted into the barrel. This will ensure close packing of the granules and eliminate the air between the granules.
  • Once the PV and SV values are the same, place the plunger provided with the machine along with the dead weight on it into the barrel. After placement of the plunger, there will be extrudate coming out of the die/orifice placed in the lower end of the barrel.
  • When the time cycle on the digital timer will complete, the cutter will automatically cut the extrudate from the barrel. This can also be done manually if the machine is set to manual operation.
  • The first extrudate that is cut by the knife is discarded. The extrudate cut afterwards should be considered for testing. Weigh the extrudate cut from the barrel using a digital balance. This weight will be used for calculating the Melt Flow Index of the sample.
After following these steps, you can calculate the MFI value of the sample with the use of the formula mentioned below:
MFI = Weight of sample in gm/ 10 min.
If you want a free sample testing session for the use of this quality testing equipment then you can give us a call at +91 9210903903 or email us at Our team of technical experts will consult you regarding all your needs and queries.
Author : -Gaurav Malhotra

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