The bond is one of the most important (but often overlooked) components of diamond tooling. The tools are often categorized into a select few groupings like hard, medium or soft metal-bond, hybrid/ semimetal bond, and wet or dry resin bond. In general, there is not a good appreciation for the multitude of variations of the bond in each of those overly simplified category classifications. The key to solve tooling problems is in understanding the bond.

Bond Hardness – Soft / Medium / Hard

There is no universal hardness designation on concrete diamond tooling, it is a relative scale. There is a big difference in the tooling used on a low horsepower lightweight class of machines versus a high horsepower heavy class machine. So for a medium bond designed for normal grinding conditions on one class machine would be completely different on a different class machine.

Metal bonds are good for larger diamonds with diamond mesh sizes up to 400G (practically more likely around 200G). Resin bonded diamond tools have a much softer bond to allow the smaller diamonds to release more freely as the tool is used (up to 6500G buff pads but practically more likely 3000G).

Resin bond tooling can be very complicated to fully understand, but for discussion purposes it can be simplified to wet or dry resin tools. The big difference is mainly in the extreme temperatures in dry grinding can melt the resin or polymers or sometimes soften them enough so the diamonds in the bond can wiggle enough to create a socket which leads to diamond pullout. There are many techniques for the diamond tool maker in selecting a resin and using different types of coated diamonds or admixtures in the resin to create more aggressive and longer life tooling. These lead to group of diamond tools called transitionals (sometimes also referred to as hybrids or semimetals).

Dressing the Diamond Tool

Many times when the diamond tools are made, the top surface of the diamonds are covered with the bond. It is important to break-in (also referred to as dressing) the diamond tools to expose a layer of diamonds. Some resin tools burn a fine waffle pattern in the top surface of the tool to speed up the break-in process. Many of the metal bond tooling are dressed at the factory by the diamond tool maker. It is important to certain that new resin bond tools are properly broken-in before making a final production run.