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The tester is a motor-driven instrument
for moving a weighted test strip over a printed specimen
through an arc. The SUTHERLAND® Ink Rub Tester, the industry
standard for decades, has recently undergone some
significant changes to enhance its utility and reliability.
Combined with a new ASTM (American Society for Testing and
Materials) recommended practice for its use, the Tester is
an excellent position to enjoy even more widespread use in
the coming years. The result of this work is an affordable
abrasion-testing instrument that retains all the features
that made it an industry standard plus improvements that
ensure it will remain the industry standard in the new
millennium. The cover shows the new tester.
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In 1990 the stroke of the SUTHERLAND® Ink Rub Tester was
shortened, which increased the precision and more closely
simulates abrasion damage found in the field. Research and
other published work in the print-abrasion-testing arena
have shown that quick strokes simulate some types of rub
damage (most notably shipping damage). One of the biggest
problems with the use of the SUTHERLAND® had been the lack of
a well-publicized test procedure for its use. While a
procedure is available with the instrument, there was no
nationally available method that could be readily
referenced. This has now been corrected with the
introduction by ASTM of ASTM D-5264 Ð 92, Standard Practice
for Abrasion Resistance of Printed Materials by the
SUTHERLAND® Ink Rub Tester (copies available from ASTM). This
method is spelled out the proper procedure for using the
SUTHERLAND® Tester.
Included in this method is the recommendation to use
standard receptors of known abrasiveness when
conducting a test.
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The SUTHERLAND® 2000 motor now has four speeds; the first
speed (21 cycles per minute) is half the speed of the older
models; which will make the wet tests, and tests using under
5 strokes easier to perform. The second speed (42 cycles per
minute) and third speed (85 cycles per minute) are the same
as the older models, while the fourth speed (106 cycles per
minute) is faster. These new improvements will allow the
customer the ability to customize the testing procedure more
to their individual product, yet maintaining the ability of
duplicating a procedure used by someone with an older model
unit. The higher speeds will reduce the long test times
needed for certain types of substrates (plastics, UV
varnishes, printed films, etc.).
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The SUTHERLAND®
2000 incorporates a digital counter with a fiber
optic sensor to ensure the accuracy of the number of
rubs for a given test. Simply enter the number of
rubs desired and the instrument will shut off
automatically after the correct number of strokes.
Changes to the control board programming will now
allow the unit to stay on for 60 minutes before
automatically turning off the LED display. Also,
after the display has turned off, pressing any
button will automatically display the last number of
strokes entered, allowing time to record results
without having to hold down the count button and
reenter the strokes with each test. |
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A single mounting pad for the test strip is cut to fit the
weight. It was found by using a two-inch (5cm) by four-inch
(10cm) pad on the bottom of the weight that precision of the
test increased. Two-pound and four-pound weights and scoring
fixture are included.
A supply of 80 x 80 count bleached muslin cloth (cloth not
included) has been found useful in testing wet smear, wet
rub, and wet bleed.
Although the SUTHERLAND® Ink Rub Tester was originally
designed to fill a need for testing the scuffing or rubbing
resistance of inks used in the paper and paperboard
industries; today it is being used by manufacturers of
cleaning compounds, waxes, floor tile, film and many other
items. The test results are reproducible.
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