3M™ ESD Floor Tile 8400 Series Versus Rubber TileTechnical Brief—June, 2008Experiment & Technical Brief courtesy of Justin P. McKay, 3M Electronics

Solutions Division, Technical Aide

IntroductionTwo important features of any ESD tile flooring are its electrical properties and

mechanical properties, namely its electrical and abrasion resistance. With these

critical attributes comes critical significance in maintaining the properties of the

tile flooring so that it may continue to serve its purpose. There is no doubt that all

flooring, despite its composition or functionality, is frequently subject to destructive

forces, most often abrasive in nature. Accordingly, it is not only important for an

ESD tile to have an electrical resistance within a certain specified range, but also,

it is crucial for an ESD floor tile to be resilient and durable, saving the customer

money in replacement costs in the long-term. 3M has created a product with these

critical features. In addition to its ability to maintain electrical integrity independent

of wear and tear through the depth of the tile, many of 3M’s customers have reported

that the 3M ESD Floor Tile 8400 Series is unique in the industry in its ability to be

cleaned repeatedly and then buffed to a high sheen, without ever using wax.

The purpose of this document and its corresponding experimentation is to clearly

illustrate the superior qualities of the 3M ESD Floor Tile 8400 Series when

compared to a similar rubber product. This information will provide 3M sales

representatives with easy-to-understand evidence in support of the benefits a

potential customer would obtain by choosing to switch to the 3M product.

Equipment & InstrumentationThe Taber® Abraser, Model 503, is a precision built test instrument designed to

evaluate the resistance of countless types of surfaces to rubbing abrasion, in such a

manner in which variables are controlled and experiments (made) are repeatable.

The rub-wear dynamic of the Taber Abraser is a product of the contact interface

between the test sample, rotating about a vertical axis at a constant 70 rpm, and

Figure 1. Taber® Abraser with H18 Abrading wheels

1 kg weights

the abrading wheels, of which there are several types and compositions with

varying degrees of abrasiveness. One of the abrading wheels rubs the specimen

inwards towards the center, while the other rubs the specimen outwards toward the

periphery. A unique and critical feature of the Taber Abraser is that the abrading

wheels traverse a complete circle on the surface of the specimen, thus revealing

abrasion resistance at all angles relative to the grain or weave of the test material.

Procedures & Materials I. Apparatus

Taber1. ® Abraser, Model 503

Taber H18 (Type CE19A1) Calibrade2. ® wheels (non-resilient wheels composed of

vitrified clay and silicon carbide abrasive particles)

Two 1 kg Taber weights3.

Vacuum Pick-up Assembly4.

ProStat PRS-801 Resistance System and probe measuring instrument5.

Digital Caliper6.

II. Abrasion (Durability) Test & Resistance MeasurementsThis experiment was designed to determine the relative performance capabilities of

the 3M™ ESD Floor Tiles 8400 Series when compared to a rubber product. Before

subjecting the samples to the abrasion test, which were conducted in accordance

with ASTM Designation D 4060, each sample’s thickness was carefully measured

at randomly chosen locations. Samples were then subjected to 3,000 revolutions

of abrasion using Taber H18 (Type CE19A1) Calibrade® wheels applying 1 kg of

pressure each. These wheels are non-resilient and are composed of vitrified clay

and silicon carbide abrasive particles. In order to assess the electrical integrity of

the tile in response to cycles of abrasion, resistivity measurements were taken at

predetermined intervals, in four equally spaced locations. These measurements

were conducted using a ProStat PRS-801 Resistance System and probe measuring

instrument. After continuing this process for 3,000 revolutions of abrasion, thickness

measurements were again taken at haphazardly determined positions. By calculating

the percent change from initial thickness to final thickness, one may acquire insight

into the relative resiliency of the materials.

Results and DiscussionAfter conducting the experiment for duration of 3,000 revolutions, the acquired data

was deemed to be sufficient to achieve conclusive results with clear implications. In

the table below you can see the thickness measurements for each tile as well as the

calculated percent change in thickness over the duration of the abrasion.

Figure 2. Taber® Abraser, Model 503

Table 1. Thickness measurements taken before abrading and then after 3,000 cycles

3M Tile Rubber Tile

Initial 3,000 rev. Initial 3,000 rev.

3.24 mm 3.16 mm 1.95 mm 0.91 mm

3.31 3.2 1.97 0.84

3.31 3.18 1.96 0.86

3.23 3.16 1.97 0.85

3.25 3.17 1.96 0.88

3.268 3.174 1.962 0.868

% Change 3% % Change 56%

From the initial measurements, one may first notice that the rubber tile is a relatively

thin specimen when compared to the 3M™ ESD Floor Tile 8400 Series; thus, even

if the products were subject to equal abrasive forces and had equal resiliency to

physical degradation, the rubber tile would have a shorter product life. In addition to

this implication, the calculations for percent change in thickness provide insight into

the rate at which each tile’s surface wears down. The average percent change for the

rubber tile is 56%, while the 3M ESD Floor Tile 8400 Series experienced a mere

3% average change in thickness. These quantities provide indisputable evidence

supporting that 3M’s ESD Floor Tile is exceptionally more resilient to abrasive

action than the rubber product. The figures to the right contain photos of each

sample after subjection to 3,000 cycles of abrasion.

As pictured in Figure 3, the conductive layering has been completely worn away

after 3,000 revolutions; in this condition, the tile is completely dysfunctional and

would not produce the effect for which it was purchased. Also seen in Figure 3, the

rubber tile contains a layer of rubber beneath the conductive material, which was

exposed after being subjected to the abrasion test. In fact, small areas of rubber

started to become visible after approximately 2,200 revolutions. The assumption

is that the electrical properties would begin degrading near 2,200 revolutions and

continuing to 3,000 revolutions, the surface is essentially bare of all conductive

material.

Considering the presence of the rubber layering, which was not accounted for in

thickness measurements, it would be logical to approximate that the conductive

material is only about as thick as the difference between initial and final

measurements, equaling roughly 1.1 mm. In contrast, the 3M tile consists entirely of

conductive material and is designed to maintain electrical integrity even when worn

down to a mere sliver.

Figure 3. Rubber tile after 3,000 abrasion cycles

Figure 4. 3M™ ESD Floor Tile after 3,000 abrasion cycles

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Electronic Solutions DivisionStatic Control Products6801 River Place Blvd.Austin, TX 78726-90001-866-722-3736www.3M.com/static

In summation, the experiment produced results that support the 3M™ ESD Floor Tile

as a product of significantly greater quality. Three key points serve as the basis for

this generalization:

The 3M ESD Floor Tile 8400 Series provides approximately 3.25 mm 1.

of conductive layering while the rubber product only provides 1.1 mm of

conductive layering.

The 3M tile degraded at an average rate of 31.33 nm/cycle while the rubber 2.

product degraded at an average rate of 364.65 nm/cycle, more than ten times that

of the 3M tile.

After abrading the rubber tile for approximately 2,300 revolutions, electrical 3.

properties were tremendously altered as a result of rubber exposure through the

disintegrating conductive surface. In comparison, the 3M tile maintained nearly

constant electrical properties for the duration of the 3,000 cycles of abrasion.

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Important Notice The information we are furnishing you is being provided free of charge and is based on tests performed at 3M laboratory facilities. While we believe that these tests are reliable, their accuracy or completeness is not guaranteed. Your results may vary due to differences in test types and conditions. This information is intended for use by persons with the knowledge and technical skills to analyze, handle and use such information. You must evaluate and determine whether the product is suitable for your intended application. The foregoing information is provided “AS-IS”. In providing this information, 3M makes no warranties regarding product use or performance, including any implied warranty of merchantability or fitness for a particular use.

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