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What can be tested with this instrument?
The standard set-up is for rigid specimens that are 4” square and less than 1/2" in thickness (shims are used to ensure the surfaces are flush). The applications are typically transparent plastics, but can also be plastic, wood, metals and other rigid parts that have been painted or printed. If you are not sure if this instrument will work for your application, submit specimens through the “Taber Test Your Samples” program.
Can this instrument test contoured surfaces?
Using a custom specimen holder, materials of various shapes may be tested. An optional 4 inch deep tray is available to accommodate these parts. To generate useful data, it is important to recognize that the amount of abrasive media will change based on the curvature of the part which may influence the test result. Also, specimens with a severe contour may inhibit the movement of the abrasive media during the test.
What is the Bayer Test?
The Bayer test is used to determine the abrasion resistance of ophthalmic lenses, and is used to replicate normal abrasion to the front of the lens. This test is applicable to all plano lenses, and compares the specimen to a control lens.
How are the test parameters changed?
The Oscillating Abrasion (Sand) Tester stroke length is adjusted manually. By changing the location of the cam roller scotch yoke drive, stroke lengths can be set between 0.25” to 6”.
What types of abradants are available?
There are a variety of standardized abradants that could be used with this instrument. The two abradants that are currently referenced in recognized test methods include quartz silica (quartz sand) and alumina (zirconia). Other potential abradants include glass bead, silicon carbide, aluminum oxide. For repeatable test results, the sizing and shape of the abradant is absolutely critical.
How much abrasive media is required per test?
According to test method ASTM F735, the tray should be filled such that the test specimen is covered to a uniform depth of 12.5mm (1/2 inch). The ‘Bayer test’ requires 500 grams of abrasive grain to be evenly distributed on the left side of the pan.
How often can the abradant be used?
During testing, the abradant may become ‘worn’ as the sharp edges contact the specimen and other abrasive particles. To ensure reproducibility, new abrasive media should be used for each test. It is also recommended that the abrasive be replaced after 300 cycles for longer tests.
How are erosion tests conducted?
To convert the Oscillating Abrasion (Sand) Tester to perform erosion tests, the 4 inch deep tray is suggested along with a specimen tray cover. In place of the abradant, a slurry would be used (i.e. 50 – 50 mixture of solids and distilled water). The abrasivity of the slurry is dependent on the concentration of the solids in the liquid vehicle, along with the characteristics of the solid particles (shape, hardness, size, and friability).
How are test results interpreted?
For transparent products, the results are measured by the change in haze. For opaque products, results would be based on a visual inspection or weight loss (depending on the coating, this may be insignificant).
What is the power requirement?
The instrument can be connected to 115 or 230 volt, 50/60 circuits. Two power cords are provided along with the appropriate fuses.
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