LCR7000 & RHEOSIGHTS P/N: 974194 |
Rev: A
|
ECO: 52468
www.dynisco.com
From lab to production,
providing a window into the process
-53-
Accuracy
The PRT'S on DYNISCO POLYMER TEST Inc. rheometers are calibrated
to NIST traceable standard temperature boxes, which are recalibrated
every 6 mo. by NIST. Die diameters are checked with hardened, class
X gage pins (+/- 20 millionths accuracy). An accurate die diameter
measurement, particularly at very small die diameters, is the most
critical item for achieving accurate results. Die lengths are checked
with micrometers for flat dies. For those with entrance cones a
matching cone is inserted and the overall length measured. Capillary
length is back calculated through trigonometry. Piston tips and length
are checked using hand or laser micrometers. Force cells are
calibrated using a calibration cell, which is calibrated with dead
weights that are NIST traceable.
NIST does provide standard reference materials for melt indexers,
which can be used on rheometers though they tend to be expensive.
ASTM also has a group of standard materials for those who wish to
participate in round robin testing. All are welcome to contact the
current chairperson of D20.30.08 to get involved. Many of these
materials are used as Indexer standards as well and can be used as a
good bridge in going from Indexer to more controlled capillary
rheometry.
