In the polymer and plastic production industry, it is important to ensure the quality and stability of the material. One of the most important laboratory testing instruments used for this purpose is the Melted Flow Index (MFI) Tester. This unit measures the flow properties of melted polymers, which help manufacturers maintain product quality and compliance with industry standards.

What is a Melt Flow Index Tester?

A Melt Flow Index Tester is a laboratory instrument used to determine the Melt Flow Rate (MFR) or Melt Volume Rate (MVR) of thermoplastics. It measures how easily a polymer melts and flows under specific temperature and pressure conditions.

The MFI value indicates the viscosity and molecular weight of the polymer, which are critical for processing and end-use applications.

Key Components of a Melt Flow Index Tester

A standard MFI tester consists of the following components:

1. Barrel and Die – A heated cylinder where the polymer sample is melted.
2. Piston – Applies a controlled load to push the molten polymer through the die.
3. Temperature control system – Ensures accurate heating (usually up to 400 ° C).
4. Weight system – Standard load to apply pressure (usually 2.16 kg, 5 kg, etc.).
5. Cutting mechanisms – Trim the extruded polymer for accurate measurement.
6. Digital screens and software – For recording data and analysis of test results.

Working Principle of Melt Flow Index Tester

The Effective Lab India MFI tester operates according to a simple principle:

1. Loading the Sample – A small amount of polymer granules is placed inside the barrel.
2. Heating and melting – The barrels are heated to a specified temperature (e.g., 190 °C for polyethylene).
3. Applying the Load – A Piston with a standardized weight pushes the melted polymer.
4. Extrusion and measurement – The melted polymer flows through the die, and the extrudate gathers at a fixed time (usually 10 minutes).
5. Calculating MFI – Calculation of the MFI weight of the extruded polymer is measured and the melted flow rate (g/10 minutes) is calculated.

Melt Flow Index Tester Uses

The MFI tester is widely used in:

• Plastic Manufacturing Industry – Ensures consistent melt flow for injection molding, casting, extrusion and blow casting.
• Quality Control Laboratory – Verifies polymer batch consistency.
• Research and development – Evaluate new polymer formulations.
• Recycling Industry – Checks the flow properties of recycled plastics.

Compliance with Industry Standards

MFI testers follow international standards such as:

• ASTM D1238 (American Society for Testing and Materials)
• ISO 1133 (International Organization for Standardization)
• BS 2782 (British Standards)

Using a compliant MFI tester ensures accurate and repeatable results.

How Does a Melt Flow Index Tester Work?

1. Sample preparation – Dried polymer pellets to remove moisture (if necessary).
2. Preheating – The barrel is heated to the required temperature.
3. Loading & compression – The sample is loaded and a preheated time is allowed.
4. Extrusion Under Load – The piston applies force under load, and the polymer extrudes.
5. Cutting and Weighing – Extracted materials are cut at intervals and weighed.
6. Result Calculation – MFI is calculated based on the extruded mass per unit time.

Key Features to Look for in a Melt Flow Index Tester

While choosing the right MFI Tester, consider:

• Exact temperature control (± 0.2 °C accuracy)
• Multiple test modes (MFR and MVR measurement)
• Automatic cutting system (For frequent results)
• User-friendly software (data logging and analysis)
• Durable construction (stainless steel component)
• Compliance with ASTM/ISO standards

Frequently Asked Questions (FAQs)

Q1. What is the purpose of the Melt Flow Index Test?

The test determines the flow capacity of melted plastic, affecting processing behaviour and product quality.

Q2. What is a good Melt Flow Index value?

It depends on the polymer and application. A high MFI indicates low viscosity (simple flow), while a low MFI means high viscosity.

Q3. Can an MFI tester measure both MFR and MVR?

Yes, advanced models can measure both melt flow rate (g/10 min) and melt (cm³/10 minutes).

Q4. How often should an MFI tester be calibrated?

Regular calibration (every 6-12 months) is recommended for accurate results.

Q5. What factors affect MFI results?

• Temperature variations
• Polymer moisture
• Incorrect test load
• Improper die dimensions

Melt Flow Index Tester Price

The price of an MFI tester varies depending on functions, specifications, brand and compliance standards.

• Basic model: ₹1,50,000 – ₹2,50,000
• Advanced Digital Model: ₹3,00,000 – ₹5,00,000

For competitive prices and high-quality MFI testers, contact Effective Labs India.

Conclusion

A melt flow index tester is an important tool for polymer manufacturers, which ensures the stability of the product and compliance with industry standards. Measuring plastic flow properties helps optimize production processes and maintain high-quality product output. Go to Effective Lab India or contact us today at +91 9555515525 or email info@effectivelabindia.com for the best-in-class MFI testers visit Effective Lab India or contact us today!