Tech Talk
What are “Abrasive Belts and Coated Abrasives”?
The term coated abrasives refers to abrasive grain which has been adhered to a backing. There are three components to a coated abrasive product: the abrasive grain, the adhesive or coat, and the backing material. All of the abrasives are used in the manufacturing of coated abrasive products. Aluminum oxide is the most popular and is used in the majority of coated abrasive applications. The abrasive is hard and durable, as well as being low in cost. Aluminum oxide is a tough abrasive and lends itself to applications that require heavy pressure. Grinding high tensile strength steel, metals, and hard woods are the prime reasons for using aluminum oxide.
Garnet is a semiprecious stone formed from a natural spinel. A spinel is a chemical formation of a metal and aluminum oxide. It is deep red in colour and is used as a natural abrasive, in particular by the woodworking industry. It is often heat treated to increase its friability and improve its cutting ability in coated abrasive applications.
A new abrasive which is an agglomerated grain has been created by the 3M Company. Small grains of abrasive have been bonded together to make a grain somewhat like the microcrystalline CBN. Such an agglomerated grain will break down under heavy load and give the abrasive belt a property much like the self-dressing capability of a vitrified bonded grinding wheel.
The coated abrasive is selected according to the grain size which will yield the required surface finish. Both aluminum oxide and silicon carbide are available in grain sizes from 12 to 600. However, very intricate and detailed forms cannot be machined using coated abrasives. The coated abrasive belt can be made to conform to a shoe or formed platen, allowing the finishing of contoured parts, such as golf club heads, water faucet spouts, and surgical implants.
