Grit Feeder  

The Taber® Grit Feeder Attachment is used in conjunction with the Taber Rotary Platform Abraser (Abrader) to evaluate three-body abrasion caused by the destructive action of fine, hard particles.  Originally referenced as the Frick-Taber test, this instrument has been used to determine the wear resistance of flooring products with smooth surfaces.

Description

The Grit Feeder is a freestanding instrument that requires a Taber Rotary Platform Abraser (not included) to conduct testing.  The grit distributor nozzle is positioned over the Taber Abraser specimen in front of the right abrasive wheel.  During the test, abrasive grit particles are deposited uniformly and continuously onto the specimen surface.  As the specimen holder rotates, the loose grit particles pass under a pair of S-39 Leather-Clad Wheels.  The resulting rolling action of the particles serves as the abradant and contributes to the physical breakdown of the material.  The vacuum hose from the Taber Abraser is inserted into the base of the Grit Feeder allowing a pickup tube to be positioned such that grit particles and debris are removed.  The operation of the grit feeder is controlled through the Taber Abraser, ensuring that the turntable, grit distribution and vacuum suction are actuated at the same time.

   

Models

Two Grit Feeder models are available.

Grit Feeder - Model 155 offers a hopper capacity of approximately 1,300 grams.  Mounted on the left side of the Taber Abraser, Model 155 utilizes an alignment guide screw to set the position of the instrument. The grit distributor and vacuum removal nozzle heights are adjusted using a thumbscrew.

Grit Feeder - Model 255 offers a hopper capacity of approximately 4,500 grams.  An alignment block is incorporated into the base of the Model 255, to ensure the correct location of the grit feeder in relation to the abraser.  A hand crank controls the telescoping feature allowing precise height adjustments and testing of thicker specimens (up to 40mm with the Taber Abraser Arm Height Extension Kit).  With the ability to mount on either the right or left hand side, two instruments can be used in conjunction with Taber's dual Rotary Platform Abraser.

Note: To use older versions of the Taber Grit Feeder with Taber Abraser Model 5135 or 5155 equipped with the Grit Feeder Control Output connection, a Grit Feeder Control Box (sold separately) is required.

Abradants

The standardized abradant supplied with Taber's Grit Feeder is a #240 aluminum oxide grit particle (Model S-41).  Produced specifically for Taber Industries, this aluminum oxide has tighter controls for both particle size analysis and bulk density properties compared to "off-the shelf" aluminum oxide.  To calibrate the rate of flow and to measure the abrasive rate of the abradant, S-38 Standardization Plates are utilized.

Prior to use, the abrasive grit should be screened through U.S. Standard Sieve No. 80 to break up any conglomerates and to remove any oversized or foreign particulate matter.  Afterwards, dry the grit for 1 hour at approximately 82° C (180° F).  Allow to cool in a temperature and humidity controlled room prior to use.

To satisfy test method EN 14354 and ISO 24338 Method B, Alodur ESK 240 aluminum oxide grit should be used.  Contact Taber Industries for additional information.

Evaluation

The following are commonly used methods for reporting Grit Feeder test results:

Weight (Mass) Loss - The weight loss test method is a quantifiable method that records the weight loss of your test specimen due to abrasion.  This method of evaluating test results is recommended when the results are to be compared with those of similar materials having nearly the same specific gravity.  Weigh your test specimen before and after testing to obtain the initial and final weight values.  The difference between these two values, F_total, is the weight loss.

      F_total = A - B

      where  A = weight (mass) of specimen before abrasion, mg

                B = weight (mass) of specimen after abrasion, mg

Use the following formula to calculate average mass loss, F_m, in milligrams (mg) per 100 cycles:

      F_m = (F_total / n) x 100

      where  n = total number of revolutions

When performing the weight loss method, loose particulate may adhere to specimens during testing.  It is critical that you clean off the test specimens as best as possible prior to weighing.

Taber Wear Index may also be used to present weight loss data.  This measurement is the loss in weight in milligrams per thousand cycles of abrasion.  The lower the wear index, the better the abrasion resistance quality of the material.

      Taber Wear Index = (F_total x 1000) / n

Cycles to a Specific End Point - The number of cycles required to reach a predetermined end point (e.g. wear through to the substrate).  Alternatively, this could be reported as the condition of the specimen after subjecting it to a specified number of cycles.

According to test method EN 14254 (Wood based panels - Wood veneer floor covering Annex D Test method to determine the wear resistance), wear generated with the Taber Grit Feeder is evaluated using a transparent template with each quadrant divided into four sectors of 22.5°.  The transparent template is placed on the test piece to determine if there is continuous wear in 12 sectors out of 16; and continuous wear through in 1 sector per quadrant.  If there is not sufficient contrast between the substrate and coating, a contrast marking solution may be used (e.g. water based solution of 1% Methylene or Alkali blue).

Volume Loss Method - In comparing the wear resistance of materials having different specific gravities, a correction for the specific gravity(s) of each material should be applied to the weight loss to give a true measure of the comparative wear resistance.  The use of this correction factor gives a wear index related to the loss in volume of the material to which it is applied.

Determine the specific gravity of the material to be tested in accordance with standard practice.  If the specimen is not homogeneous, but possesses a surface that differs from the body or core, determine the specific gravity of the surface alone.  If abrasion is to be carried beyond the surface of the body, also determine the specific gravity of the latter and calculate and report the abrasion resistance of the two components separately.

      Volume Loss, cm³ = (W₁ - W₂) / S

      where  W₁ - weight of specimen before abrasion, g

                W₂ = weight of specimen after abrasion, g

                S = specific gravity

Depth of Wear Method (Thickness) - Certain test requirements may call for measuring the depth of wear.  To determine this, mark four points on the back of an unabraded sample, 90° apart and oriented 11/2" (38 mm) from the center hole [this will be within the wear path].  Using a thickness gage or micrometer, measure the specimen thickness.  After abrading the sample, repeat the measurements and record the difference.  To compensate for depth differences around the specimen wear path, an average should be computed from the four readings.

Change in thickness can also be measured using an Optical Micrometer or similar instrument.  Place the measuring device so that it spans both the abraded and unabraded portion of the specimen.  Calculate the amount of wear by measuring the difference between the abraded and unabraded areas in four equadistant points around the specimen, and average the results.

Alternatively, the average loss in thickness can be calculated by dividing the loss in volume by the abraded area of the specimen.

Test Methods

The following link provides a listing of test methods the Taber Abraser (Abrader) and Grit Feeder Attachment satisfies.  Please note, additional accessories may be required.

Falling Sand Abrasion Tester  

The Falling Sand Abrasion Tester - Model 820 is a popular apparatus used to measure the resistance to abrasion of paint, lacquers and other organic coatings.  Abrasion results from abrasive particles falling through a guide tube and impinging the test specimen, until the substrate becomes visible.

Description

Based on a design described in ASTM D 968 and other internationally recognized test standards, the Falling Sand Abrasion Tester consists of an 8" diameter sand reservoir which includes a 60° taper funnel.  Standardized abrasive particles placed in the reservoir are released to a guide tube by an abrasive flow gate key.  The guide is a 36" straight, smooth-bore tube which contains the abrasive particles as they fall.  Specimens are fixed under the guide tube at a 45° angle in a receptacle that includes an opening at the bottom allowing the abrasive particles to be collected in a container.  A sturdy base and support system hold the apparatus in a vertical position.

Abradants

Although a variety of abrasive particles have been used, silica sand and various grades of silicon carbide continue to be most popular.  To ensure reproducible results, the abrasives must be graded to a particular sieve size.

Note: Silica sand is typically characterized by its roundness of grains and produces a slower rate of abrasion on organic coatings.

It has been noted that for 3 mil dry film thickness, many of the older coatings would require 20 to 200 liters of silica sand to achieve a failure.  Today's more durable coatings may require up to 600+ liters of sand to wear-through.  For an extremely durable coating, the Taber Rotary Abraser is preferred as the Falling Sand method tends to be laborious and time consuming with the handling of large quantities of abrasive.

Evaluation

Abrasion resistance is often expressed in terms of the volume of abrasive required to wear through a unit thickness of the coating.

Test Methods

The following link provides a listing of test methods the Taber Falling Sand Tester satisfies.  Please note, additional accessories may be required.

Oscillating Sand Abrasion Tester  

The TABER® Oscillating Abrasion Tester - Model 6160 is best known as an "oscillating sand tester". Described in ASTM F735 (Standard Test Method for Abrasion Resistance of Transparent Plastics and Coatings Using the Oscillating Sand Method), the oscillating sand tester is used to measure the relative abrasion resistance of a material to surface abrasion and / or marring.  The primary application of the Oscillating Sand Abrasion Tester is for transparent materials and coatings utilized in windows and lenses, but it might also be used to evaluate organic paints & coatings, plastics, metals and other materials.

Description

Rigid specimens that are 100mm square and less than 12.5mm in thickness are mounted in a holder located in the bottom of a sand tray so the surface is flush within 1mm.  The tray is filled to a uniform depth (e.g 12.5mm) with a standardized abrasive media such as quartz silica or alumina.  A scotch-yoke drive system reciprocates the tray in a back-and-forth (to-and-fro) motion which causes the entire mass of the abrasive media to shift significantly within the tray.  The oscillating movement of the abrasive media results in a random pattern of scratches which simulates normal everyday wear.

Test parameters can be altered with Taber's Oscillating Sand Abrasion Tester, and allow the operator to select the operating stroke length (6.5 to 150 mm) and speed (variable from 100 - 200 cycles per minute).  ASTM F735 specifies the sand tray travels a distance of 100mm at a speed of 300 strokes per minute.

In addition to the dry abrasion test, the oscillating sand abrasion tester may be used with abrasive slurry to perform erosion tests.  For this application, the optional 4 inch deep tray is suggested along with a specimen tray cover. In place of the abradant, a slurry would be used (e.g. 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).

Using a custom specimen holder (not supplied), materials of various shapes may also be tested.  To generate useful data, it is important to recognize that the amount and force of abrasive media that contacts the specimen surface will change based on the curvature of the part.  Specimens with a severe contour may inhibit the movement of the abrasive media during the test.

An optional kit is available to conduct the Bayer Abrasion Test on contoured lenses. This set-up involves testing a specimen against a control lens for comparative purposes.

Abradants

In December 2011, Taber Industries learned that the sole source provider of the 4/10 abradant described in section 6.1 of ASTM F735 was sold and the new company discontinued the product.  The ASTM subcommittee responsible for this test method is working on initiating a round robin study to characterize / qualify a potential replacement material.  The recommended material is a 6/9 Silica Abrasive Media which is available from Taber Industries.  If you would like more information, please contact us.

There are a variety of standardized abradants that could be used with this instrument.  Besides the silica abrasive media, other potential abradants include alumina (zirconia), silicon carbide, aluminum oxide and glass bead.  For repeatable test results, the sizing and shape of the abradant is absolutely critical.

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 cycle tests.

Evaluation

Using a haze meter, the haze and light transmission of a transparent test specimen is measured and recorded.  After subjecting the specimen to the specified number of abrasion cycles, the results are measured as a change in haze and light transmission.  Abrasion resistance for opaque materials is measured visually or by weight loss.

Test Methods

The following link provides a listing of test methods the Taber Oscillating Sand Abrasion Tester satisfies.  Please note, additional accessories may be required.

Crockmeter  

The Taber® Crockmeter - Model 418 provides a quick and accurate method to determine the amount of color transferred from textile materials (such as fabric, carpeting, yarn and leather) to other surfaces by rubbing.  The Crockmeter has also been employed to perform rub abrasion, scuff and / or mar tests on flat specimens.  Plus, it can be used to conduct smudge and smear resistance tests on images produced by a printer or copier.  Regardless of specimen material, both wet and dry testing can be performed.

Description

Originally designed to simulate the action of a human finger and forearm, the Crockmeter uses a standard pressure and rubbing motion to provide reliable and reproducible test results.  Specimens are positioned on the base of the Crockmeterand held in place with the sample holder. To prevent the specimen from shifting during testing, a sandpaper pad is provided to place under the specimen.  A hand crank moves a reciprocating arm a distance of approximately 100mm. The rubbing action is provided by a 16mm diameter acrylic "finger" which moves back and forth in a straight line with each complete turn of the crank. The reciprocating load arm is weighted to provide a constant 9N load on the sample at all times and a mechanical counter keeps track of completed cycles.

Abradants

A standardized crocking cloth is most often used as the abradant for textile applications.  This square (or sometimes circular) cloth is wrapped around the acrylic crock "finger" and held in place with a wire spring clip.  AATCC Method 8 specifies the cloth should meet the following specifications:

Fiber	100% 10.3 - 16.8mm combed cotton staple, desized, bleached, with no optical brightener or finishing material present
Yarn	15 tex (40/1 cotton count), 5.09 turns/cm "z
Thread Count	32 +/-3 warp ends/cm: 33 +/-3 picks filling/cm
Weave	1/1 plain
pH	7 +/-0.5
Mass/sq. meter	113 +/-5g greige: 100 +/-3 g finished)
Whiteness	W = 80 +/-2

 

Other abradants that might be used with the Crockmeter include felt, duck cloth, laboratory grade denim, coated abrasives (e.g. Polishing Paper, 281Q 3M WetorDry™), etc.

Evaluation

Typical evaluation for textile Crockmeter tests involve visually comparing the amount of color transfer / staining against a standardized color transfer scale.  After rubbing the crocking cloth against a colored test specimen for the prescribed cycles, the crocking cloth is removed from the instrument and the amount of color transferred to it is compared to a known scale and assigned a grade. Two popular scales include AATCC Gray Scale for Staining or the Chromatic Transference Scale. For repeatable and reproducible test results, it is recommended that specimens be evaluated in controlled lighting and at a specified angle.

When using the standard 16mm diameter crock finger to test pile fabrics (such as textile floor coverings), there may be heavier staining on the circumference of the stained area of the crocking cloth. To resolve this, Test Method AATCC 165 describes using a "crock block" measuring 19.0 x 25.4mm.

Test Methods

The following link provides a listing of test methods the Taber Crockmeter (Crock Meter) satisfies.  Please note, additional accessories may be required.

Heavy Duty Linear Abraser 

The TABER® Heavy Duty Linear Abraser - Model 5800 is used to evaluate material properties of products with a rugged, durable surface finish that require an increased testing load or longer stroke length.  Supplied with the 2" diameter Universal Attachment and Scotch-Brite™ scouring pads, the Heavy Duty Linear Abraser is ideal to measure a coating's resistance to scrubbing with an abrasive scouring pad.  A popular application includes evaluating non-stick coatings used on cook / bake ware.

Description

Similar to Taber's Linear Abraser, a test attachment is secured to the bottom of a vertical spline shaft and accessory weights may be placed on a weight holder affixed to the top.  A precision bearing on the spline shaft creates a "free-floating" test system.  As the test arm moves in a linear motion, the "free-floating" system will raise or lower as the test attachment follows the contours of the specimen being tested - curved or flat.

The base load of 500 grams consists of the test attachment, spline shaft and weight holder.  Accessory weights of 1000, 2000 and 4050 grams are included and can be added to the weight holder to increase the test load.  With a high torque motor, the Heavy Duty Linear Abraser can accommodate a maximum testing load of 20 lbs. (weight sold separately).

Other features of the Heavy Duty Linear Abraser include a slotted roller channel allowing stroke length adjustments up to 330mm (13 inch); five preset speeds including 15, 30, 37, 45, and 60 cycles per minute; and an integrated T-slot table for securing specimens during testing.

With interchangeable attachments, the Heavy Duty Linear Abraser can also be configured similar to the Linear Abraser to evaluate the relative resistance or susceptibility of a material surface to wear and abrasion, scratch, gouge, scrape, rub, and more.  In addition, the instrument can be used for both wet and dry testing.  To increase test output, an optional second test arm kit may be added to perform two tests simultaneously.

Caution: Not all interchangeable attachments will accommodate the heavy test loads possible with the Heavy Duty Linear Abraser.

Evaluation

Tests conducted with the Heavy Duty Linear Abraser using the Scotch-Brite™ scouring pads are normally performed until the surface coating has been worn down to the substrate material or a portion thereof (breakthrough).  Alternatively, tests can be run for a predetermined number of cycles (e.g. 10,000) with mass loss used as the end point.

Test Methods

The following link provides a listing of test methods the Taber Heavy Duty Linear Abraser (Abrader) satisfies.  Please note, additional accessories may be required.

Reciprocating Abraser (Abrader)  

The TABER® Reciprocating Abraser (Abrader) - Model 5900 is a test apparatus similar to the instrument described in test method ISO 1518.  Ideal for flat surfaces, this tester can be configured with optional attachments to evaluate the relative resistance or susceptibility of a material surface to physical damage such as wear and abrasion, rub, scratch, mar, gouge, scrape, plus others.

Click here for information on scratch testing with the Reciprocating Abraser.

Description

The Taber Reciprocating Abraser includes a counterbalanced arm which pivots on an adjustable height gantry system.  The counterweight allows the user to balance the test arm, ensuring precise test load set-up regardless of the weight of the attachment.  Incorporated at the end of the arm is a tool holder to which optional attachments and weights may be secured.  A sliding specimen platform moves in a horizontal, reciprocating motion under the stationary tool holder.

Test parameters such as stroke length (6 - 155mm), speed (3 - 75 cycles per minute) and load (1N - 24N maximum, with included weights of 1N, 2N, 2.5N, 5N, 10N & 24N) are adjustable so optimal settings for each material can be established.

To expand test loads, an optional weight support may be affixed to the top of the tool holder.  This permits using auxiliary weight discs originally intended for Taber's Linear Abraser 5750 in place of the standard weights supplied with the instrument.  Weight discs are sold individually and available as 10g, 20g, 50g, 75g, 100g, 150g or 250g.

The Wearaser® collet assembly comes standard with each Taber Reciprocating Abraser, along with CS-10 and H-18 Wearaser abradants.  The size and shape of a pencil eraser, the Wearaser is made using the same high quality Taber abrasive media found in our Genuine Taber abrading wheels.  This permits the use of equivalent abrasive materials with the Reciprocating Abraser as well as Taber's Linear Abraser and the Taber Rotary Platform Abraser.

The standard specimen table provided with the Reciprocating Abraser is 216mm x 278mm (8.5" x 11") with drilled tapped holes to accommodate specimen clamps or optional specimen fixing plates.  To evaluate most flat specimens, specimen clamps or the optional Wide Slot Fixing Plate may be suitable.  For flexible materials such as textile products, the optionalSpecimen Fixing Plate Kit  might be used.  Products with a slight contour can also be secured in place using the specimen clamps provided or a custom fixture.

The Reciprocating Abraser can accommodate two additional test arm kits (sold separately), permitting up to three tests to be performed simultaneously.

Wear / Abrasion Attachments

For information on Wear / Abrasion Attachments for the Reciprocating Abraser, click here.

Evaluation

Due to the wide variety of test attachments that can be used with the TABER Reciprocating Abraser (Abrader), there is no universal method to interpret results.  The two most common methods include:

Cycles to a Specific End-Point - The number of cycles required to reach a predetermined end point, or the appearance or condition of the specimen after a fixed number of cycles.  The evaluation criteria may include: loss in coating, change in gloss, color loss, or other changes in appearance.  In these cases, the abraded sample is usually compared to a known standard of the material tested.  When visually inspecting changes in specimen appearance, evaluations should be made using an agreed upon rating system such as a visual grading scale (e.g. five-step) or pass/fail criteria.

Weight (Mass) Loss - This technique measures how much material has been removed by abrasion, and is usually reported in milligrams.

      L = A - B

         where L = weight loss

                A = weight (mass) of specimen before abrasion

                B = weight (mass) of specimen after abrasion

Linear Abraser (Abrader)  

The TABER® Linear Abraser (Abrader) - Model 5750 has been engineered to test either contoured or flat surfaces, making it ideal to evaluate finished products of all sizes.  To expand the versatility of this instrument, the Linear Abraser can be configured with optional test attachments to perform different types of abrasion tests.  And can be used for both wet and dry testing.

Click here for information on additional attachments that can be used with the Linear Abraser to evaluate the relative resistance or susceptibility of a material surface to scratch, mar, gouge, and scrape.

Description

The Taber Linear Abraser incorporates a horizontal arm that reciprocates in a linear motion.  Attached to the end of the arm is a precision bearing spline shaft that creates a 'free-floating' test system and permits vertical movement.  The test attachments are affixed to the bottom of the spline shaft and a weight support is mounted to the top.  As the horizontal arm strokes back and forth, the test system raises or lowers vertically as the test attachment follows the contours of the specimen.  A laser alignment guide assists with specimen set-up to ensures the abradant travels over the desired area.

Adjustable settings enable the user to select the speed, stroke length and test load.  The Linear Abraser includes six preset speed buttons, along with the ability to adjust the speed from 2 to 75 strokes per minute.  Eleven stroke lengths are standard ranging from 0.2 inch to 4.0 inch.  The base load of the "free-floating" test system is 350 grams and consists of the test attachment; spline shaft; and weight support.  Three 250g weight discs are supplied with the instrument and optional weight discs ranging from 10 to 250 grams can be added to the weight support to increase the test load to approximately 2100 grams.  Optional accessories can be also be used to decrease the load.  For example, an 150mm aluminum spline shaft and plastic Wearaser Collet Kit can bring the minimum load on the sample to as low as 60 grams.  Taber's Linear Abraser is programmable to 999,999 cycles, but caution must be used as the abradant may wear prior to the end of the test.

The Wearaser® collet assembly is supplied with each Taber Linear Abraser, along with CS-10 and H-18 Wearaser abradants.  The size and shape of a pencil eraser, the Wearaser is made using the same high quality Taber abrasive media found in our Genuine Taber abrading wheels.  This permits the use of equivalent abrasive materials with the Linear Abraser as well as Taber's Reciprocating Abraser and the Taber Rotary Platform Abraser.

The Multi-Head Attachment (sold separately), incorporates an additional spline shaft, permitting two tests to be performed simultaneously with the Linear Abraser.

With the diversity of products that can be tested with the Taber Linear Abraser, it is up to the end-user to determine a suitable clamp or fixturing device appropriate to their product.  Click here for additional information on specimen mountingavailable from Taber Industries.

Wear / Abrasion Attachments

For information on Wear / Abrasion Attachments for the Linear Abraser, click here.

Evaluation

Due to the wide variety of test attachments that can be used with the TABER Linear Abraser (Abrader), there is no universal method to interpret results.  The two most common methods include:

Cycles to a Specific End-Point - The number of cycles required to reach a predetermined end point, or the appearance or condition of the specimen after a fixed number of cycles.  The evaluation criteria may include: loss in coating, change in gloss, color loss, or other changes in appearance.  In these cases, the abraded sample is usually compared to a known standard of the material tested.  When visually inspecting changes in specimen appearance, evaluations should be made using an agreed upon rating system such as a visual grading scale (e.g. five-step) or pass/fail criteria.

Weight (Mass) Loss - This technique measures how much material has been removed by abrasion, and is usually reported in milligrams.

      L = A - B

      where L = weight loss

             A = weight (mass) of specimen before abrasion

             B = weight (mass) of specimen after abrasion

Note: There is no standard formula to correlate test results between the Linear Abraser and Taber Rotary Abraser.  Due to differences in how the wear paths are generated, testing parameters and the unique wear properties of each material prevents a universal formula from being devised.  If you are attempting to correlate the results, Taber recommends correlating through experimentation to determine the appropriate settings.