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.
 


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.

 


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.).

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.

 

 

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.