Grinding wheels are abrasive compound-containing wheels used for grinding and abrasive machining processes. These kinds of wheels are also utilized in grinding machines.
Wheels are typically made of composite material. A cementing matrix (called the bond in grinding wheel terminology) presses and bonds coarse-particle aggregate together to form a solid, circular shape. Depending on the intended function of the wheel, various profiles and cross-sections are available. They can also be constructed from a solid steel or aluminum disc with particles adhered to the surface. Most grinding wheels today are artificial composites consisting of artificial aggregates; however, the history of grinding wheels began with natural composite stones, such as millstones.
Because of the inherent safety risks of a spinning disc, as well as the composition and uniformity required to prevent that disc from exploding due to the high stresses produced by rotation, the manufacture of these wheels is a precise and tightly controlled process.
Grinding wheels are consumables, with lifespans ranging from less than a day to many years, depending on the application. Individual grains of abrasive are periodically released as the wheel cuts, typically because they become dull and the increased drag pulls them out of the bond. This wear process exposes new grains, kicking off the next cycle. This process's wear rate is usually very predictable for a given application and is required for good performance.
The grinding wheel must first be secured to the grinding machine before it can be used. The wheel type (e.g., cup or simple wheel below) fits freely on their supporting arbors, with identically sized flanges (metal discs) applying the necessary clamping force to transfer the rotating motion to the side of the wheel. The paper blotter in the photographs is meant to distribute the clamping force uniformly throughout the surface of the wheel. Click here for Continuous Diamond Wheel.
Although grinding wheels can, to a limited extent, sharpen themselves, for best use, they should be dressed and trued using wheel or grinding dressers. To expose a new, sharp surface to the work surface, the current layer of abrasive must be removed from the wheel. By trueing the wheel, the grinding surface is brought into alignment with the grinding table or other reference plane, producing an accurate surface throughout the whole surface.