A diamond cup wheel is a common tool used to grind concrete, granite, marble, and some other materials. It is a kind of metal-bonded diamond tool, and consists of some diamond segments and a metal (often steel) wheel body. Its wheel body often looks like a cup. Diamond cup wheels are often used on angle grinders and big concrete grinders.
The performance of a diamond cup wheel is mainly determined by its diamond segments, which consists of metal bonding materials and diamonds. As different concretes, granites and marbles have different natures, the bond materials and the diamonds used in the segments should also be different. When the workpiece is hard, the bond should be softer to let the new diamonds be exposed more easily and participate in the grinding; when the workpiece is relatively soft, the bond should be harder to hold the diamonds longer to extend the wheel’s service life.
The diamond grit of the wheels can be coarse (e.g., 35/40 grit), medium (e.g., 60/70 grit), and fine (e.g., 120 grit), which can be used in the steps of the grinding process.
The bond of coarse wheels should be softer and the diamonds’ quality should be higher, because in this case the diamonds are more easily to become blunt. The grit should be bigger, for big grit can improve working efficiency for coarse grinding. The diamond concentration can be lower.
The bond of fine wheels should be harder and the diamonds’ quality can be lower, for in this case the diamonds can last longer and hard bond can hold the diamonds longer and can also benefit the precision of the processing. The fine grit is normally between 80 grit to 120 grit, depending on the grinding requirements. The diamond concentration should be higher.
There are a variety of styles of diamond cup wheels for different application requirements. The dimension and number of their segments determine how aggressive the wheel is. The wheel with big and crowded segments are usually used in grinding, while the ones with sparse segments can be used for fast removal of paints, wallpapers, glues, epoxy and other surface coatings.
Diamond cup wheels can be made via two methods: hot pressing and cold pressing. The hot pressing method is usually like this: first the diamond segments are made via hot pressing method with dedicated sintering press machine, and then these segments are silver brazed onto the wheel body. While the cold pressing method is: first the metal bonding materials and diamonds are pressed to the segment form on the wheel body, and then they are put into sintering furnaces and are sintered without press. As the segments of hot-pressed diamond cup wheels are denser and can last longer, and their form is regular, they are popular in professional users. While the cold-pressed wheels are cheaper, and their lifespan is shorter and their form is often not so regular, they can be used in DIY applications. diamond painting