M0726(2):LMFI Series 5000 Lab Melt Flow Indexer
37
English 02/2014
Cleaning Up
If using hand weights without the lift system, push down slowly on the weight and purge any
material remaining in the barrel through the die and out of the barrel. If using a weight lift
system, you may want to turn off the “Auto Raise” feature to allow the test weights to dwell at the
end of the test and purge any remaining material from the barrel. Remove the piston rod by
twisting it clockwise to break the seal created by the molten plastic then pull straight up.
Warning
:
If you pull the rod out too quickly you may cause a suction that pulls the
die out along with the rod which may lead to a very hot die coming off and travelling
through the air or onto the floor or some other undesired location.
While wearing protective gloves, wipe the piston rod with a cotton rag. Remove
the die with the die removal tool. Put two cleaning patches directly over the barrel about 1/2 way
overlapped and, using the cleaning tool, push the patch down into the barrel. Run the patch up
and down a half dozen times or so, and then repeat the process. A minimum of two sets of
patches are generally needed to clean the barrel properly, however, some materials are
harder to clean that others. Repeat the process until used patches come out clean. When the
system is clean, put the die and piston plunger back into the barrel. This allows the piston
plunger and the die to reheat before the next test.
With materials that are thermally stable (less than 5% viscosity change over 1/2
hour of heat exposure) we recommend only cleaning the barrel between every second run or
between changes to different material. For materials that degrade or are moisture sensitive it is
recommend that both the barrel and the die be cleaned completely between each test. To clean
the die, use the die removal rod and push the die up from the bottom of the barrel and out the top.
Wipe it with a cotton rag and clean it by running the drill bit through it several times. Remove
material that collects in the grooves of the drill bit and repeat until the drill passes easily through
the die. Scrape the die with the sample cutting knife if needed to clean the top and bottom faces.
For materials that crystallize quickly you can clean the die by first running a drill bit up into the die
while it is hot and in the indexer. This will make it much easier to get the cleaning drill bit inserted
when the die is removed and the material starts to solidify.
USER TIP:
Experienced users often listen for a double bounce of the die when they drop it back
into the barrel to know that the barrel is clean.
Also, while the die is out of the barrel, look down the barrel bore to be sure it is
clean (use safety glasses when looking down the barrel and beware of noxious fumes that may
come from heated material inside!). Ensure the inside surface of the barrel is smooth and shiny
when completely clean.
