Download to MS-DOS compatible systems
Methods A, B, or A/B conversion and flow rate ratio
Automated purge or weight lowering
Control temperature within 0.1
C.
Automatic check of RTD sensor probe and over temperature alarm.
On Overview of MI
A flow rate test is a measure of a polymer's mass flow rate (grams extruded in
10 minutes) using a particular orifice under specified conditions of temperature
and load. Machines that determine flow rate are generally called Melt Indexers.
Test methods by ISO, DIN, ASTM and others specify heat chamber and piston
tip diameter such that the shear stress on the polymer is the same in all machines
for a given load. In addition, material specification guidelines (by ISO, DIN,
ASTM, GM etc) may exist which give further constraints on how a particular
type of material may be run.
The tests we are interested in performing are those described by ASTM D1238
and ISO 1133. This manual in no way supersedes either of these documents.
The precision and accuracy of the test has been determined by ASTM method
D1238 and can be found at the end of this manual. Contributing to both
precision and accuracy are operator variances such as; packing technique,
cleaning, cutting, weighing etc. With moisture sensitive polymers, dryness can
also play a major role, and time can be a factor with thermally unstable
polymers, so procedures must be identical.
Dynisco Polymer Test Systems
has
found that charging a consistent mass of material into the barrel (
0.1 grams) is
the most critical factor in getting precise data.
ASTM Melt Index Tests
Two basic methods have been developed for running flow rate tests under D-
1238, Methods A and B. Method A is simply the collection of extrudate over
time, while Method B is the measurement of time for the flow of a fixed volume
of polymer.
Method A
Method A/B
Method B
Introduction
Method A
-- the test is completely manual and is sometimes called the "cut-n-
weigh" method.
Method A/B
-- this employs the electronic eye or digital encoder. In order to
run a method B test, an A/B run MUST be run first to determine the polymer's
melt density
Method B
can be conducted only after an A/B experiment is conducted. This is
a "no-cuts" test that is the most convenient for busy laboratories.
Series 4000 Product Offerings:
The Series 4000 of melt indexers are actually 2 pieces of equipment in one.
First, the instrument
houses the hardware
needed to conduct the measurement
itself -- the heaters, temperature sensors, die/orifice assembly, and so on.
Series 4000 Melt Indexer Operation Manual
Introduction
3
