Abrasion Tester

The Taber Abrasion Tester is a single platform rotary abrasion tester. It preforms accelerated abrasion testing primarily on fabrics, but can also test plastics, coatings, laminates, paper, carpets, and ceramic. It operates by affixing a sample to the platform via a stud, 8mm in diameter. The platform then rotates. It can revolve with two speeds, 60 RPM, or 72 RPM. Two abrading arms lie above the platform. Different abrasion disks and weights can be attached to the arms, depending on the type of material being tested. The test is then run for a set number of cycles, and the durability of the sample is characterized via the wear and tear. This can be done qualitatively or quantitatively.

	Taber Rotary Abrasion Tester [SOP]
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Platform Size	~ 100 mm$^{2}$
Speeds	60 RPM, 72 RPM
Stud Diameter	8 mm

Sample Prep

For fabric or other flexible samples must have a 8 mm diameter hole cut/drilled in the center so that it can be slid onto the stud. Samples should be large enough in size to be draped over the platform; this implies a diameter of ~110 mm. The center piece should be tightened over it with a nut, and the hold down ring should be tightened down on top, to prevent the sample from moving during the test.

Rigid samples should also have an 8 mm in diameter hole drilled in the center. The sample should be cut to 100 mm square. A diameter of 100 mm is also acceptable. It is secured withe the center piece and nut clamping it down at the stud. The hold down ring is not necessary. Recommended sample height is 6.35 mm, higher samples may not be testing without the necessary accessories to do so.

Choice of abrasion disk is heavily dependent not the material being tested. Refer to the SOP for more details on the use of specific wheels.

Opperation

The two abrading disks are designed so that one will abrade the sample towards the center, and the other will scrape it outwards towards the edge of the sample. Thus, as the sample is spun under the two abrading wheels, it will be worn in all directions relative to any potential grain or weave in the material. The total area of the sample to be abraded will cover approximately 30 cm$^{2}$.

Data Analysis

There is not a standard unit or method of measuring abrasive wear. However, there are still many methods of measuring the abrasive resistance of a material. Some rely partially on qualitative judgements, while others are purely quantitative.

Cycles until End Point

The simplest method of quantifying abrasive resistance is in terms of the number of cycles required to reach a specified level of degradation. Reaching this level may be determined via visual qualitative clues, or through quantitive criteria, such as loss of mass, loss of breaking strength, yarn breakage, ect.

Mass Loss

Another simple method of determining how much a material has been worn down is by measuring the loss in mass. Because the vacuum removes all debris, this measures how much of the material as been removed from the whole by the abrasion disks. However, you must ensure that the sample is well cleaned, and precisely weighted before starting. Mass loss is calculated simply as the change in mass of the sample from before testing til after testing. Test settings must remain unchanged for this to be comparable to other samples.

Taber Wear Index

This measures the mass loss, per cycle. It can be calculated with this formula: $I={\frac {1000\times (M_{f}-M_{i})}{C}}$, where I is the Taber Wear Index, C is the number of Cycles, and $M_{f}{\text{ and }}M_{i}$ are the final and initial masses, in milligrams, of the sample.

Volume Loss

This method is used to evaluate the results of materials with different specific gravities. Specific gravity is a measure of the density of a material compared to the density of a known reference usually water. To compare two such materials with varying specific gravities, the Taber Wear Index would be calculated for each material, and the index number would then be divided by the respective specific gravity. This would provide changes in volume, which could then be used to compare the two materials.

Residual Breaking Force

This evaluation technique is applicable mainly to textiles for fabrics. Tensile testing can be done on some samples before abrasion testing, and on others after abrasion testing. The difference in breaking force required for these tests shows how much weaker the sample has become as a result of the abrasion.

This can also be given as a percent loss in breaking force. Determine the pre and post test breaking loads, and use this to calculate the percent loss of breaking strength. This should be done for the fabric both lengthwise and widthwise. The average is then calculated according to this formula: ${\text{AR}}={\frac {100\times (X-Y)}{X}}$, where AR is the abrasion resistance, X is the percent loss of breaking strength in lengthwise, and Y is the percent loss of breaking strength widthwise.

Depth of Wear

Abrasion can also be characterized via the change in depth of the material which has been abraded. When testing coatings, this is sometimes reported as the number of cycles required to wear through a coating of known depth.