Basics About Grinding Wheels

Abrasives are a common tool in manufacturing, in fact, without abrasives, our planes wouldn't be able to fly and our cars wouldn't be able to drive. In common grinding, one of the most commonly used abrasive products is the grinding wheel! Modern abrasives have evolved into highly complex technical products used to manufacture very complex components from some of the hardest alloys and materials known. Grinding wheels mainly include abrasive grains, bond and grit.

1. Abrasive grains

Abrasive grains provide the basic function of a grinding wheel as they grind the surface of the workpiece. Several commonly used grinding wheel abrasives are ceramic alumina, zirconia alumina, aluminum oxide, white alumina, aluminum oxide, and silicon carbide. Abrasive grains can also be blended together to achieve different performance characteristics.

2. Bonds

A bond is a substance that makes the abrasive grains adhere to the grinding wheel. Bonds can be composed of different materials. Common materials include shellac, resin, rubber, and glass or glass-ceramic. The bond on the wheel can be hard or soft. A harder bond extends the life of the wheel if the user handles and maintains the wheel properly. Softer bonds allow smoother grinding and expose new grains more quickly. Grinding wheel bonds sometimes contain iron, sulfur, and chlorine, which can cause problems if they stick to the workpiece during grinding, so you should avoid such wheels. Over time, the bond on the wheel exposes new grains, helping to provide a consistent stock removal rate. As the older grit wears away, the grit breaks off as designed, exposing a new abrasive surface, while the new grit stays where it was. Under normal operating conditions, abrasion removes worn abrasive particles and leaves behind new ones, maintaining the wheel's excellent cut rate and performance.

3. Grit

Grinding wheel grit is essential to provide the correct wear. Grit measurements typically range from coarse to fine. Selecting the proper grit grade for a specific application helps ensure adequate grinding capacity. Coarser grits have better removal rates, while finer grits require less pressure during application and allow for a better final finish on the workpiece.

When choosing a grinding wheel you need to consider the diameter and thickness of the grinding wheel. The diameter of the grinding wheel usually depends on the tools available. Selecting the correct diameter also increases safety as it allows the use of proper guards. Larger diameter wheels last longer, especially in applications where the operator must run the wheel for extended periods of time, increasing productivity by reducing the number of times the operator has to stop and change the abrasive. The configuration of the workspace and workpiece will also affect the choice of diameter. The thickness of the grinding wheel will affect its performance and life, so the grinding wheel of the appropriate thickness is also very important.