Diamond Scratch Test
The standard criterion for scratch resistance is the minimum load required to penetrate the surface of the testing material with the diamond tool. Alternatively an average scratch width can be calculated using a specified load, and results compared.
The standard criterion for shear resistance is the minimum load necessary to shear the surface of the testing material with the contour shear tool with a typical width ranging between 1mm to 2.5mm. Due to the difficulty in cutting grooves of identical width, minor deviations can be compensated for by averaging the measurements.
Adhesion of Coatings
Using the TABER Shear / Scratch tester, adhesion of coatings can be rated. This is determined by recording when the tool breaks through the junction of the topcoat and the undercoat. See graphic for suggested ratings.
Operated by an on/off switch, the motorized turntable rotates at a constant speed to ensure greater accuracy in test results. The turntable rotates in a counter-clockwise direction, but with a simple conversion the turntable rotation can be reverse.
For materials sensitive to scratching, an optional Scale Beam Modified Weight Set is available that converts the scale by 1/10 to 0 - 50 gram range. To increase the testing load from 1000 to 1500g, an optional Scale Beam Fixed Weight is available. To satisfy EN 13310 (Kitchen Sinks - Functional requirements and test methods) an optional weight that provides a 15N load is also offered.
For best results, conduct three to four tests on the specimen surface. Each test should be approximately 90° from each other (e.g. in the 12, 3, 6 and 9 o'clock positions) and at least 6mm in length. A 10x Measuring Magnifier is included with each Shear / Scratch Tester. This allows you to visually measure the width of a scratch to the nearest thousandth of an inch.
Tester, 500 Gram Calibrated Weight (2 each), S-20 Precision Ground Tungsten Carbide Tool, Conical Diamond Tool (for 10090), ISO Diamond Tool (for 10091), Measuring Magnifier, Spirit Bubble Level, Hex Wrench