February 11th, 2021
How do you differentiate one class of abrasive grain from another? Premium abrasives are often distinguished as either natural or synthetic, and both categories can be further sub-divided into distinct materials. Material classification is ideal for the raw or powder form. But end-users looking for an abrasive finishing solution are often seeking a solid-state product where abrasive grains are confined in a binder. These are typically defined as either coated or bonded abrasives.
Both coated and bonded abrasives describe a cutting, grinding, or finishing product composed of extremely hard-wearing particles compacted into a solid form. Coated abrasives are engineered by depositing one or more layers of abrasive on a flexible substrate like a sheet or a belt (i.e. sandpaper). Bonded abrasives are made by combining premium grains with functional filler materials and bonding agents. This mixture is compressed into a final shape such as a grinding wheel, a grinding disc, or sharpening stone..
Bonded abrasives are the product of choice for industrial grinding and finishing of hard materials like metal and ceramic alloys. The nature of your workpiece is the first thing to consider when selecting an abrasive system. Standard material finishing requirements may be satisfied by commodity alumina (Al2O3), but the surface quality finish often leaves much to be desired. This is usually symptomatic of poor bulk particle properties such asbroad particle size distributions (PSDs) and/or coarse grit sizes. It may also come down to chemistry, microstructure, or various other phenomena.
A finer surface finish for hard substrates requires a bonded abrasive solution made with precision engineered grains. Alumina remains the recommended material for such applications, but a high-purity monocrystalline alternative is preferred to commodity, lower quality materials (i.e. brown-fused alumina). Compounds of alumina—zirconia also sit comfortably alongside high-purity monocrystalline alumina in terms of aggressive material removal rates with good surface uniformity, though alumina zirconia is only compatible with resin bond systems.
Selecting the right bonded abrasives subsequently comes down to an array of business and material considerations. Here we will outline a few recommended materials by application, to give you more insight into the selection criteria for bonded abrasive grains.
Saint-Gobain Abrasive Grains is the industry-leading developer of precision engineered grains for bonded abrasive applications. Interested in making the transition from commodity products to truly high performance solutions? Contact a member of the Saint-Gobain team today.