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Did you know?

Closed Diamonds

Metal-bond diamond grinding discs can become “closed” at any stage of use, from the first application through to prolonged grinding.

These discs contain diamond particles held within a metal matrix, which gradually wears away during grinding to expose fresh diamond cutting edges.

What Causes a Diamond Disc to Close?

As the disc grinds, the exposed diamond tips gradually wear down. If the metal matrix does not wear away at the same rate, the diamond tips can become flat or level with the surrounding metal matrix. This prevents the diamonds from protruding sufficiently to cut effectively into the surface.

A closed diamond is evident when the disc begins to glide across the surface, concrete, coating or screed without removing material efficiently, resulting in a noticeable reduction in grinding performance.

Solution: Reopening the Diamond

To restore cutting performance, the metal matrix surrounding the diamond particles needs to be worn back to expose the diamond tips again. This can be achieved by introducing a small amount of water or using a suitable abrasive material, such as sand, to help break down the metal matrix.

Using water: Stop the machine and apply a small amount of water to a suitable area of concrete. Grind this area until a paste-like substance forms. The abrasive action helps wear away the metal matrix surrounding the diamond particles, allowing the diamond tips to protrude and resume cutting effectively.

Using an abrasive material: Where appropriate, grinding a suitable abrasive material, such as sand, can help wear down the metal matrix and expose the diamond cutting edges.

Once the diamonds have reopened, resume grinding and monitor the disc’s performance. Always ensure the correct metal-bond specification is selected for the material being ground, as the bond must wear at the appropriate rate to maintain effective cutting performance.

Important: Follow the grinding machine and tooling manufacturer’s instructions, including any requirements for wet or dry operation. Never introduce water unless the equipment is suitable for wet grinding.

For more information or prices please contact our sales team,

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