taber test part2

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Taber Industries Responseto Info Sheet #32

By: Alan Jaenecke Taber Industries 1 March 8, 2012Email: [email protected]

For Discussion and Comment

Taber Test Continued . . .

As Information Sheet #32 (March 2011) pointed out, the Taber Abraser

is the most widely accepted international test used for predictive weartests. The versatility and simplicity of the tester has promptednumerous industries, including flooring, to reference the Taber Abraserwhen evaluating the abrasion resistance properties of their products.

What Test Methods Are Available?

The Taber Abraser has been utilized to test a variety of flooring options ranging from varnishes,vinyl, stone, laminate and industrial coatings. Although each is a flooring product, the procedurefor each material may be different. This is often the case for similar products such as woodcoatings too! Therefore, unless the test reference and test variables are included with the data,the results should not be compared.

Selecting which method to use is typically decided by industry organizations, or left to theinterested parties. The most commonly referenced Taber test methods for wood coatingsinclude:

Reference Title Scope

ASTM D154 Standard Guide for Testing Varnishes This guide covers the selection and use of procedures for testingvarnishes. Some test methods are included, but most sections refer tospecific ASTM test methods (references ASTM D4060).

ASTM D4060 Standard Test Method for Abrasion Resistance ofOrganic Coatings by the Taber Abraser

This test method covers the determination of the resistance of organiccoatings to abrasion produced by the Taber Abraser on coatingsapplied to a plane, rigid surface, such as a metal panel.

ASTM D6037 Standard Test Methods for Dry Abrasion MarResistance of High Gloss Coatings

Two test methods are included. Test Method A uses a device thatcontains an abrasive wheel. Test Method B uses a device thatcontains a wheel that has been fitted with abrasive paper. Eithermethod can be used to evaluate the dry abrasion mar resistance of

coatings applied to planar, rigid surfaces.EN 13696 Wood flooring - Test methods to determine elasticity

and resistance to wear and impact resistanceThis document specifies two alternative test methods to determine theresistance to wear of lacquered wood floorings and one method to testthe elasticity of the lacquer.

EN 14354-AnnexD

Wood Based Panels - Wood Veneer Floor Covering This method of test specifies a procedure to determine the resistanceto wear of lacquered wood veneer floor covering.

ISO 7784-1 Paints and Varnishes; Determination of Resistanceto Abrasion

This part of ISO 7784 specifies a method for determining theresistance to abrasion of a dried film of paint, varnish or relatedproduct, using abrasive paper attached to wheels and abrading bymaking a rotary movement

ISO 7784-2 Paints and Varnishes; Determination of Resistanceto Abrasion

This part of ISO 7784 specifies a method for determining theresistance to abrasion of a dried film of paint, varnish or relatedproduct, using abrasive rubber wheels and abrading by making arotary movement

JIS K 5600: Part5, Section 8

Testing Methods for Paints {Part 5: Mechanicalproperty of film -- Section 8: Abrasion resistance(Rotating abrasive paper covered wheel method)}

This Standard is one of a series of standards dealing with thesampling and testing of paints, varnishes and related products. ThisStandard specifies a method for determining the resistance toabrasion of a dried film of paint, varnish or related product, using

abrasive rubber wheels and abrading by making a rotary movement.JIS K 5600: Part5, Section 9

Testing Methods for Paints {Part 5: Mechanicalproperty of film -- Section 9: Abrasion resistance(Rotating abrasive rubber wheel method)}

This Standard is one of a series of standards dealing with thesampling and testing of paints, varnishes and related products. ThisStandard specifies a method for determining the resistance toabrasion of a dried film of paint, varnish or related product, usingabrasive rubber wheels and abrading by making a rotary movement.

NOTE: Specific methods may vary with regards to abrasive wheels, load, vacuum nozzle gap, etc.


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Understanding the Results

The Taber Abrasion test provides a means to quantify the abrasion resistance of materialsurfaces. Results may be related to end-use performance, but are not intended to be an exactrecreation of wear that occurs. This is because resistance of material surfaces to abrasion, as

measured on a testing machine in the laboratory, is generally only one of several factorscontributing to wear performance as experienced in the actual use of the material. Other factorsinclude mechanical properties of the specimen such as elasticity, hardness, strength (bothcohesive, tensile, and shear strength), toughness and coating thickness. In addition, varioustypes of soil and foot traffic can influence the durability of varnish films on floors.

The mechanism of wear depends upon the topography of the counter face abradant. Abrasiontests utilizing the Taber Abraser may be subject to variation due to changes in the abradantduring the course of the test. Depending on abradant type and test specimen, the abradingwheel surface may change (i.e. become clogged) due to the pick-up of coating or other finishingmaterials from the test specimens. To reduce this variation, resurfacing instructions arestipulated in most standards, specifying that the abrading wheels shall be resurfaced prior to thestart of testing and / or at regularly defined intervals.

Taber tests are most frequently used to demonstrate a comparative ranking of materialperformance. As the wear rate depends on the material, type of wear, and the contact conditions,one should not assume that the wear rate is a linear function of time or number of contact cycles.

Do Not Believe Everything You Read

Because the Taber Abraser is a rugged instrument and relatively easy to use, operators forgetthis is a precision instrument that requires regular maintenance. It should not be surprising thatdata generated with instruments not properly maintained or calibrated would result in a statisticalanalysis showing low correlation. This point is raised not to discount the validity of historical data,but rather for users to be aware of these concerns when interpreting data. Two examples specificto the flooring industry that demonstrate this are presented below.

In an independent study conducted by the laminate flooringindustry in 2005, the importance of calibration was recognized asa significant contributor to sources of variance. The studyconcluded that improper alignment of the abrasive wheels canlead to each wheel abrading a different path from itscomplementary wheel across the sample as well as the wheelson other machines. Path surface area can differ by as much as20% and the area abraded by both wheels on a sample could beless than 50% of the total abraded area for that sample. Thepotential sources of error identified by this study include bearingwear (looseness), shaft wear and alignment of the arms. Thesecoincide with similar parameters Taber Industries advocates

checking with the Calibration Verification Kit.

ASTM D4060 included the statement Because of the poor reproducibility of this test method, itshould be restricted to testing in only one laboratory when numerical abrasion resistance valuesare to be used. Inter-laboratory agreement is improved significantly when rankings of coatingsare used in place of numerical values. In 2006 an updated round robin study was conducted forthe test method, but prior to generating any test data all instruments were required to becalibrated. After compiling the result, the reproducibility and repeatability improved significantlywhich prompted ASTM to eliminate the above statement.


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Additionally, Information Sheet #32 (March 2011) discussed a known waterborne coating thatwas evaluated over a 10 year period by various laboratories. Noting the coating was tested byvarious laboratories at various times, the information sheet listed a number of testing factors thatcould explain the variation within and between this series of tests. It should be mentioned thatinstrument calibration was not included in this listing.

Looking Forward

There are multiple Taber test procedures that can be employed to measure the wearperformance of a coating. To reduce the concern about comparing data generated using differenttest parameters, it is essential that any test report be prefaced with a description of the testparameters (including abrasive wheel, load, vacuum nozzle gap, sample conditioning, etc.).

Should the Australian Timber Flooring Association establish a unified test protocol for testingabrasion resistance of coated flooring? We invite you to submit your comments for publicdiscussion. Any comments please email Randy [email protected]
mailto:[email protected]:[email protected]:[email protected]:[email protected]

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