Features, Specifications and Working Principle of Rubbing Fastness Tester

Last Updated on 20/12/2021

Crocking and Crockmeter:
The rubbing off of colors is called as crocking. Crocking is simply the transfer of color from a fabric onto another white test fabric. The more color is transferred, the more the fabric “crocks”. Crocking determines the amount of color transferred from the surface of colored textile material to other surfaces by rubbing. The crockmeter / crockmaster is used to find the color fastness to rubbing / crocking. It is also called rubbing fastness tester. It is one of the best machines that you can use to test the color transference of fabrics.

In order to determine the color fastness of dyed or printed textiles or leather, this test is used for the determination of color fastness against rubbing, either under dry or under wet conditions.

Crockmeter / Crockmaster is an scientific equipment of physical testing of textiles. There are two types of crockmeter; Electronic Crockmeter and Manual Crockmeter.

The Crockmeter equipped with an electronic counter, and handle is on the top to take it easy. A sandpaper is set under the test sample so that the sample is fixed during the test, makes the rubbing color fastness test repeatable.

Features of Crockmeter:
Here are some features that make it possible for a crockmeter to determine the color fastness of fabrics such as leather, dyed, and printed textiles.

1. To determine the Color Fastness of Rubbing.
2. The equipment consists of a counter.
3. It is provided with a flat peg.
4. It also consists of an operating handle.
5. Tests the color fastness of the textile in a very accurate manner.
6. It gives not only accurate but quick results also.

Technical Specifications of Crockmeter:

• Diameter of the Rubbing Finger: 16 mm & 25 mm
• Load on the Finger: 9 N & 20 N
• Size of Crocking Cloth: (5 x 5) cms & (7 x7) cms
• Length of the Traverse: 100 ±5 mm
• Counter (Re-settable): 4-Digit Counter
• Size of Test Specimen: 25 x 5 Cm
• Overall Dimension of the Unit: 600 (W) x 190 (D) x 200 (H) mm
• Net Weight of the Unit: 4 Kg. (9 lbs.)
• Construction: Cold-rolled steel

How Does The Crock Meter Work?
To determine the color fastness of fabric, take a piece of fabric and soak it in either distilled or deionized water. After removing the excess water from the fabric, attach it at the end of the finger of the instrument.

Once mount the fabric on the sample placement platform, set the number of cycles on the machine so that it runs against the piece of fabric. The results get show the color fastness which translates to the quality of the fabric.

Working Principle of Crockmeter:

1. The crockmeter consists of a rigid flat metallic platform on which the test specimen can be held firmly and a abrading finger which rubs against it under a specified load.
2. The platform is fixed over the base of the equipment and lies in a horizontal plane.
3. The test specimen is held firmly over an abrasive paper which is pasted on the upper face of the platform, with the help of two pins holding it at both ends.
4. The abrading finger has a flat circular rubbing face which is covered with 4 piece of white abradant fabric during the test.
5. The abradant fabrics picks up color lost by the test specimen during rubbing.
6. It is held over the finger with the help of a tapered ring.
7. Motion to the finger is given through a reciprocating arm with runs an two ball bearings to minimize friction and to apply a uniform load on the finger.
8. The arm is moved by a manually operated crank and connecting lin. The equipment is finished in dark metallic paint and bright chrome plating to give it a corrosion resistant finish.

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Mazharul Islam Kiron

Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. Mr. Kiron is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.

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