9. Procedure A—Manual Operation
9.1 Select conditions of temperature and load from 8.2 or in
accordance with material specifications. Where multiple test
conditions exist, test conditions shall be agreed upon by the
cooperating laboratories. If test conditions are not known,
select conditions that result in flow rates between 0.15 to 50
g/10 min.
9.2 Inspect the extrusion plastometer for cleanliness (see
Note 10). All surfaces of the cylinder bore, die and piston shall
be free of any residue from previous tests.
NOTE 10—The degree of cleanliness can significantly influence the
flow rate results, therefore a thorough method of cleaning should be
established. It has been found that swabbing the barrel with a clean cotton
patch several times is satisfactory for most materials and that the die,
barrel, and piston are more easily cleaned while hot. For materials that are
difficult to clean from the metal surfaces, use of a brass brush has been
found to be satisfactory.
9.3 Check the die bore diameter at frequent intervals with
appropriately sized go/no-go gauges (checked with die at
23 6 5°C) to verify that the die is within the tolerances given
in 5.3.1. Visually examine the die bore to verify that it is not
scratched or damaged. Also visually inspect the land of the
piston foot to verify that it is not scratched or damaged and use
a calibrated micrometer to verify that the dimensions are within
the tolerances given in 5.4.1 (see Note 11).
NOTE 11—Cleaning and usage will eventually cause damage or wear to
the, bore, die and the land of the piston. Data has shown that erroneous
results will be obtained if these components are not within the appropriate
tolerances.
9.4 Set the temperature in accordance with the manufacturer’s
instructions.
9.5 Insert the die and the piston into the bore. Allow the
temperature of the cylinder, with the piston and die in place, to
stabilize within 60.2°C of the selected test temperature for at
least 15 min before starting a test. When equipment is used
continuously, it is not necessary to heat the piston and die for
15 minutes when runs of the same or similar material at the
same test temperature are being measured over a continuous
time frame, provided the piston and die are cleaned and
re-inserted into the bore within five minutes after removal from
the extrusion plastometer at the end of each test. If the piston,
or die, or both, are removed from the bore for longer than five
minutes, they shall be considered “cold” and the full 15
minutes heating stabilization time shall be required.
9.6 Remove the piston from the bore (see Note 12). Within
60 seconds, charge the cylinder with a weighed portion of the
sample in accordance with the expected flow rate (as given in
Table 1), reinsert the piston and add the appropriate weight.
The charging weights given in Table 1 are merely suggestions,
and the actual charging weight for a specific sample, if not
known, will need to be determined by trial and error. Adjust the
charge weight so that the piston is in the proper position at the
end of the pre-heat period. If necessary, it is acceptable to
purge excess material from the cylinder bore so that the piston
is in the proper position at the end of the pre-heat period.
Purging of material done at conditions with greater force than
testing conditions shall be completed at least 2 min prior to
making the initial cut-off (see Note 13).
NOTE 12—Placing the piston on an insulated surface after removing it
from the bore will reduce heat loss.