Method for Measuring Abrasive Grain Strength (TI/TTI)

The crushing test is currently a widely used method for evaluating abrasive grain strength, and among these tests, the ball mill flyability test is considered the most popular method for evaluating superabrasives due to its reproducibility and simple principles.
However, several precautions must be taken during measurement to ensure the reproducibility of the results.

Sample preparation (sample extraction and sieving)
Management of balls and capsules (inner diameter, indentations, cap parallelism)
Sieving and measurement of grinding media (handling, sieving, and weighing of grinding media)
Handling of results and retesting

System Configuration

Crushing Test Equipment (Flyability Tester, Ball Milling Machine): The motor’s rotational motion is converted into vertical motion via a crank, imparting a reciprocating motion to the installed capsule.

(Standard Specifications)

frequency	2400rpm
Amplitude	8.0mm
Capsule	Attach a flat end cap and a hemispherical end cap to the cylindrical capsule. The capsule can be used as long as the end caps do not wear out, but the usage limit is approximately 100 times.
Ball	2 g (It is recommended to replace it after every use, if possible)
sieve	φ75mm

Standard sieve weighing apparatus, brushes, and other items

Procedure

01 Extraction of Sample Powder

Mix the abrasive grains thoroughly, then use a vibrating screen to separate the on-size grains.

02Preparation for Crushing

Check the dimensions and appearance of both caps on the capsule, then insert two samples and the ball.
Also, turn on the power to the main unit in advance and allow it to warm up.

03Crushing

Determine in advance the rotational speed or time required to achieve approximately 50% fragmentation for each type and size of abrasive grain, and perform two grinding operations at values close to that target.

04Measurement of Abrasive Grains

Sieve the ground abrasive grains and determine the weight of the on-size grains.

Test 1: Rotation speed: A = (Weight of unground sample / Weight of sample fed into the machine) × 100 = C%
Test 2: Rotation speed: B = (Weight of unground sample / Weight of sample fed into the machine) × 100 = D%

TI (Rotation speed at 50% fragmentation) = A + (50 - C) × ((A - B) / (C - D))

Considerations for Abrasive Grain Strength Testing

This measurement method allows the strength and friability of an abrasive grain to be evaluated as “comparative values” under conditions where the same equipment and measurement method are used. It is also a testing method used for acceptance inspections in comparison with standard abrasive grains, or for comparative analysis with other abrasive grains.
When reviewing results expressed as percentages, it is particularly important to verify the rotation speed and time conditions. Furthermore, results should be evaluated only after confirming the device’s speed, amplitude, and ball size. (Do not compare results from other manufacturers based solely on numerical values.)

About Global Diamond

At Global Diamond, we aim to resolve and address any challenges or issues you may be facing with your current diamond and CBN abrasives from the following three perspectives. We go beyond simply offering catalog selections; through customization, we work closely with you to help you achieve a better final product.

Evaluation and Recommendations for Your Current Abrasive Grains
Compatible with special mesh sizes
Precision coarse-grain cutting

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We also offer contract analysis services

Drawing on the extensive data and proven track record that comes from being a specialized manufacturer that has conducted its own incoming inspections of abrasive grains, we offer contract analysis services for the samples you provide.

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