The mounting of abrasives on a support is a necessary process for the manufacture of multiple sanding, refining and polishing tools, as almost all surface conditioning materials have different types of supports.
Abrasives are usually classified according to their scale of hardness; however, within the wide range of finishing and polishing products, there are some that are known as support abrasives, which are usually tools for polishing surfaces and obtaining the desired finishes.
Support abrasives are composed of the following elements:
- Base binder
- Surface binder
- Abrasive grain
- Sanding layer
The binder and the abrasive grain are placed on the support. As mentioned above, there are different types of support, which differ in their flexibility and wear resistance.
The choice of backing is made according to the use of the abrasive tool. These are the most common types of backing for abrasive materials:
The paper used for the manufacture of abrasive tools must meet certain characteristics, such as tensile strength, flexibility, adhesion, etc.
The places where abrasives with paper supports are most frequently used are the wood and craft industries (carpenters, painters, varnishers, welders, etc.). Abrasives with this type of support are not usually used in the metal industry.
On the other hand, the paper used for manual abrasives is 70-100 g/m². And for narrow and wide abrasive belts, used in stationary machines, the support paper is heavier.
Unlike paper support, fabric support lasts longer and offers more resistance to tearing, plus it can be easily bent and folded while in use, a feature that makes it easier to work with. Cloth-backed abrasives are used especially for metal machining.
- Vulcanized fiber:
Vulcanized fiber is a material made from paper and in different thicknesses in discs, bands and sheets of sandpaper. Its main characteristics are stability, robustness and great resistance to water.
The binders act as a bonding element for the abrasive grains. These materials, of which there are several types, give the abrasives the necessary strength and hardness to withstand the demands to which they are subjected during the work for which they are used.
In the industry of supported abrasives, different binders are used to fix the grain in the support. First, the backing is coated with a bonding agent, then the abrasive grain is spread and aligned using special processes.
The bonding agent, which is intended to protect the abrasive grain, is used to make the abrasive grain firm.
There are many types of binders, but the most commonly used are vitrified or ceramic binders, resinoid or vaquelite binders, metallic binders, rubber binders, lacquer binders and silicate binders.
In short, grain refers to the type of mineral used to make abrasive tools. This material has a direct influence on both the quality of the surface finish and the cost-effectiveness of the abrasive. The most common abrasives are aluminium oxide, silicon carbide, zirconium oxide and ceramic oxide.