This video explains about MFI (Melt Flow Index) in very simple way to clear the concepts of students.

1. Melt Flow Index (MFI)

2. Melt Flow Index (MFI)
O Definition
O Importance of MFI
O Formula
O MFI Tester
O Test Procedure
O Standard Operating Procedure
O Test Standard
O Test Condition

3. Definition
O “Melt Flow Index (MFI) is a measure of
how many grams of a polymer flow
through the die in ten minutes. ”
O The test is performed at a given
temperature depending on the plastic.
O The force used to push
the plastic through the system is supplied
by a weight which sits on top of a ram.
O Unit:- gram/10 min.

4. Importance of MFI
O Melt Flow Index is a very valuable test for
quality assurance.
O Identification of Raw material.
O Comparison of "good" and "bad" samples
O Grade differentiation of materials
O Batch to batch comparisons
O Processing control parameters of the
plastic material before putting into
production.
O Verify Incoming Raw Material.

5. Formula of MFI
O MFI = 600 Sec x Weight of extrudate
t
T = Time of extrudate in seconds.
Unit – g / 10 min.

6. MFI Tester

7. MFI Tester

8.  The MFI testing methods to be followed to
ensure accuracy in the process:
 The sample should be in granulated form. No
other form or final product can be tested.
 The granules (4 to 5 grams) are charged in the
hot barrel. It has to be made sure that there is
no space within the granules in the barrel.
 Using a piston, dead weight is applied on the
granules to create a pressure and to make the
flow of the granules non-stop.
Test Procedure

10.  As the temperature of the barrel starts to increase,
the sample starts to melt.
 This molten plastic starts to come out from the orifice
(Diameter of orifice 2 mm). There is an automatic
cutter incorporated into the machine to cut the string
of the plastic that is coming out from the orifice.
 This cutter runs twice. One, before starting the test
and once after 10 minutes, which is the standard test
time.
 This molten plastic is taken and weighed. The weight
in grams is divided by 10 minutes to get the actual
MFI value.
Test Procedure

11. Standard operating Procedure
O 1. First of all turn the machine on by plugging the
mains socket of the machine into a 3 pin 15 amp
socket.
O 2. Set the SV value on the PID controller and the
test duration timing on the digital timer.
O 3. Switch on the toggle switches from the control
panel for automatic cutting of sample.
O 4. After setting the temperature and timer, turn
the heater on by pressing the heater on the
switch.
O 5. Wait for the reading in the PV display in the
PID controller to reach the value of the SV
display

12. Standard operating Procedure
O 6. After the required temperature for the test has been
attained, fill the barrel of the machine with the plastic
granules you want to test.
O 7. Poke the granules with the plunger after they are
inserted into the barrel to ensure close packing of the
granules and eliminate the air between the granules.
O 8. When the granules are inserted in the barrel, there will
be a slight decrease in the PV value on PID monitor. Wait
for this value to again reach the SV value.
O 9. Once the PV and SV value are the same, place the
plunger provided with the machine along with the dead
weight on it into the barrel.
O 10. After placement of plunger, melted plastic comes out
of the barrel.

13. Standard operating Procedure
O 11. When the time cycle on the digital timer
completes, the cutter will automatically cut the
sample from the barrel.
O 12. Weight the melted sample using a digital
balance. This weight will be used for calculating
the Melt Flow Index of the sample.

14. O There are two major MFI test standards:
O ASTM D1238: Standard Test Method for
Melt Flow Rates of Thermoplastics by
Extrusion Plastometer.
O ISO1133: Determination of the Melt Mass-
Flow Rate (MFR) and Melt Volume-Flow
Rate (MVR) of Thermoplastics.
Test Standard

15. Test Condition