Lens Abrasion and Scratch Resistance Tests.

1. AppliedOpticsAssignment
2020-2021
Bachelor of Optometry
Presenting to
Mrs.Paramita Deb
Asst Professor
SUSAH

2. TREYresearch
AboutUs
Shahin Khan,Ayusha Bhandari,
Niyanta Banepali,Shabnam Parween
& Sadikshya Magar
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Topic-
Lens abrasion & scratch
resistance tests.

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Abrasion and Scratch Resistance
Although there are several test methods for testing abrasion resistance, there is not one universally
agreed upon standard. Abrasion resistance is actually a combination of different factors—
adhesion, hardness, flexibility and impact resistance. Each test method measures a different
combination of these factors. Since each of these test methods measures a different combination of
features, they do not always correlate with each other.There are few tests —Steel wool test,Bayer
Test,Tumble test & Taber Test. Some of the most durable coatings are designed to give the best
combination of abrasion resistance as measured by several of these test methods.

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TaberTest
Taber tests involve coated or uncoated lens to a turntable
platform that rotates on a vertical axis at a fixed speed. Two
genuine Taber abrasive wheels, which are applied at a
specific pressure, are lowered onto the specimen surface.
100 cycles at a time is performed.
Weight loss is measured.
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Tabertest

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TumbleTest
Masso, proposed the Tumbling barrel test (Tumble test) for
evaluating abrasion of coated and uncoated plastic lenses. In
this test, the lenses are placed in a barrel with a mixture of
abrasives, including sand and fine emery among others, and
then tumbled (repetitive random falls) for a fixed period of time.
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SteelWoolTest
2 kg at 500 times
• Steel wool is a popular test because a version of this test
can be performed without any special equipment. There
are different ways to conduct a steel wool test. The
simplest is to rub the lens by hand with a small piece of
steel wool. This method gives a qualitative rating from
poor to excellent. There is also equipment available that
rubs the lens with steel wool under a specified weight for
a specified number of cycles. This type of steel wool test
gives a quantitative measurement. The steel wool is of
known fiber size and quality.
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Steel Wool Test

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BayerTest
The Bayer test is one of the most often cited test methods for
abrasion resistance. This test subjects both a coated lens and
an uncoated standard to abrasion from oscillating "sand." The
sand is actually alumina zirconia. After a set number of cycles,
the haze gain is measured on both lenses.
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BayerTest

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ThankYou
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