Guide to Bonded Abrasives: Grits, Grains and Types

Bonded abrasives are both natural or synthetic abrasive grains "bonded" into a tangible form, usually within a wheel's shape. Bonded abrasives include grinding and cut-off wheels, snagging wheels, segments, mounted wheels, plugs, and cones. Such quite abrasives enjoy wild applications.

What does bonded abrasive consist of?

A bonded abrasive consists of an abrasive within a matrix, although very fine alumina abrasive may comprise sintered material. This matrix is named a binder and is usually a lump of clay, a resin, a glass, or a rubber. This mixture of binder and abrasive is generally shaped into blocks, sticks, or wheels. 

Commonly used abrasive materials include alumina, carbide, boron nitride, zirconia alumina, and ceramic alumina. Artificial sharpening stones are often a bonded abrasive and are readily available as a two-sided block, all sides being a superior grade of grit.

Grits and Grains

Grinding wheels and other Bonded Abrasives have only two significant com­ponents. The par­ticular abrasive utilized in a wheel is chosen, supporting the way it'll interact with the work material. Each abrasive type is exclusive, with distinct properties for hardness, strength, fracture toughness, and resistance to impact.

• Aluminum Oxide 
• Zirconia Alumina
• Silicon Carbide 
• Ceramic Alumina 

Read More - Components of Bonded Abrasives

Every emery wheel features a number that displays its grit size. Coarse grains are suitable for rapid stock re­moval, where the finish isn't necessary. Fine grit wheels are ideal for im­parting fine finishes, for little areas of contact, and to be used with hard, brittle materials.

Types of Bonded Abrasives

There are three principal sorts of bonds utilized in conventional grind­ing wheels. Each type is capable of giving specific characteristics to the grinding action of the wheel. The selection of abrasive bond type depends on the wheel operating speed, the type of grinding operation, the precision required, and the material to be ground.

Vitrified bonds

Grinding wheels made with vitrified bonds are very rigid, healthy, and porous. They remove stock material at high rates and grind to express requirements. They're not suffering from water, acid, oils, or variations in tempera­ture.

Organic bonds

These bonds soften under the warmth of grind­ing. The primary common organic bond type is that the resinoid bond, which is formed from resin. Wheels with resin­oid bonds are good choices for applications that need rapid stock removal, and those where better finishes are needed.

Rubber bonds

Rub­ber bonds offer a smooth grinding action to the wheels. Rubber bonds are often found in wheels used for a top-quality finish, like needle bearing and roller bear­ing races. The hardness or strength of a bond is designated because of the grade of the emery wheel. The bond is claimed to possess a stringent quality if the bond posts or spans between each abrasive grain are solid and may retain the grains against the grinding forces tending to pry them loose.

Conclusion

Grinding processes can genuinely be considered engineered systems, made from four key com­ponents: machine, abrasive product, work material, and opera­tional factors. Manufacturers who want to optimize their grinding systems' productivity check out of these variables and evaluate how changes to at least one impact the others when making decisions on which emery wheel is best suited to their applications.