Diamond Tools: How to Choose Diamond Concentration

Diamond concentration of a diamond tool means the weight of the diamonds in each cubic centimeter of the diamond tool’s working layer. The international standard has prescribed that if each cubic centimeter contains 0.88g super-abrasives, its concentration is 100%. The each increase or decrease of 0.22g will cause the concentration to change by 25% correspondently.

Diamond concentration is an important feature of diamond tools, greatly influencing their cutting or grinding efficiency and their processing costs. If the concentration is too high, many diamonds will fall off the tool prematurely. This leads to the waste of the diamonds. If the concentration is too low, the processing efficiency will be decreased, and the processing requirements may not be satisfied.

When choosing the diamond concentration, we should consider bond type, diamond grit, processing procedure, the tool’s shape, etc.

Different types of bond have different hold capacities to the diamonds. Therefore there exist ranges of the best concentration value. If the hold capacity of a bond is strong, the range of its best concentration value is also high.

Below is a table for the concentration ranges of different bond types:

Bond Type	Concentration Range (%)
	Diamond Tools	CBN Tools
Resin	50 – 75	75 – 100
Ceramics	75 – 100	75 – 125
Bronze	100 – 150	100 – 150

As can be seen from the table, for a same bond type, the concentration of CBN tools is normally a little bit higher than the diamond tools’. The reason is that CBN is mainly used to process the types of steel which are tough and whereas whose hardness is lower than the material’s which diamonds are used to process.

When the grit of diamonds is smaller, the concentration should also be lower to perform precise cutting/grinding and then gain fine finishes. For example, in polishing or high-precision grinding procedure, low concentration resin bond diamond tools are frequently used, some of which’s concentration can be as low as 25%. However, in the coarse grinding procedure which has a high requirement on processing efficiency, big grit and high concentration diamond tools can work better.

In choosing diamond concentration, the shape of the diamond tool and its processing manner should also be considered. For the jobs having broad working area, especially for profile grinding which requires retaining the precision of the diamond tool’s shape, face grinding and groove grinding, diamond tools with higher diamond concentration should be chosen.