There is a wide variety of abrasive products that can be used for countless tasks in industrial and craft processes. The main characteristic of these tools is the use of natural or synthetic minerals of high hardness, which act on the surface of other less hard materials, in order to produce wear through mechanical effort and give them specific shapes and finishes. If you want to know what abrasives are and their different uses, I invite you to read on.
What are abrasives?
Abrasives are natural or synthetic elements that, due to their high hardness and characteristics, and assembled on different types of support according to their purpose (paper, fabric, fibre, vulcanized fibre or metal) are used in various mechanical procedures to polish, refine, cut and give finishes to other less hard materials.
Abrasives are classified according to their hardness capacity. For this classification, the hardness capacity is evaluated according to various scales. The most widely used is the Mohs scale, established in 1820 by the German mineralogist Friedrich Mohs.
On the other hand, among the enormous variety of abrasive products, there are many formats and sizes, arranged to perform work on different surfaces and for different purposes, among which we find rolls, sheets, strips, triangles, discs, wide abrasive belts, abrasive sponges, fibre discs, quick fastening systems, abrasive sleeves, fans with handles, fan discs, fan wheels, cutting discs, polishing discs, polishing machines and other accessories.
The characteristics of the abrasive materials
As mentioned above, there are different types of abrasives, each with specific characteristics and suitable for each material to be worked with. Among the most important attributes of abrasives are the following:
Hardness: This characteristic is defined as the resistance of an abrasive material to being penetrated by another less hard material on a scale of values between 1 and 10 on the Mohs scale, where the highest value is comprised of diamond.
Logically, the abrasive must be harder than the material to be worked on, in order to remove a surface layer of the material without excessive wear to the abrasive. The most commonly used hardness scales are, apart from the one already mentioned, Rockwell hardness, Rosiwal scale and Knoop scale.
Friability: It is the ability of the abrasive grains to break and self-sharpen under tension and by which the abrasive material works optimally to perform the desired task.
Wear resistance: It is the capacity of the abrasives to resist wear. Due to the continuous friction between material and abrasive, wear resistance is a fundamental characteristic since friction increases heat and, therefore, increases the possibility of altering the physical, dimensional and microstructural integrity of the worked piece.
Toughness: It is the capacity of the abrasive material to resist breakage and deformation. In short, it is the resistance to fragmentation of the abrasive grain.
Cutting capacity: As its word indicates, this attribute is related to the sharpness of the edges of the abrasive mineral and the scratches produced when it comes into contact with a surface.
Among the abrasive materials there are two main categories: natural abrasives and synthetic abrasives.
Natural abrasives. They are a product of nature and their origin dates back to the time when man used stones of a certain hardness against others to shape weapons and tools. Among the most common natural abrasives are quartz, garnet, emery, and natural diamond.
Synthetic abrasives. Synthetic abrasives are manufactured by processes using different raw materials and chemical reagents. Nowadays most of the natural abrasives have been replaced by the synthetic ones since the industry demands minerals with more precise and stable properties than the ones offered by the natural ones. Synthetic abrasives include aluminium oxide, silicon carbide, cubic boron nitride and synthetic diamond.
Uses of abrasive materials
Grinding: With some abrasive products, such as the grinding disc, a weld seam can be flattened or a sheet can be prepared for painting, or steel, stainless steel and aluminium can be polished to perfection.
Sanding: The purpose of this technique is to wear down or smooth a surface in order to perfect it and eliminate imperfections. Depending on the material to be sanded, it is important to choose well the abrasive material with which this task will be carried out, since if a material that is too thick or hard is used, it is possible to burn the surface.
Polishing: To carry out this task, in most cases polishing pastes are used which are usually applied with a simple cloth. With this abrasive material a professional finish and shine is achieved.
Sharpening: Sharpening is a technique widely used in all types of situations. To do this, it is necessary to exert a friction on the product by means of blades discs manufactured for this purpose.
Cutting: This is one of the most common uses made with electro-portable machinery. For this purpose, it is necessary to carefully choose the cutting discs that best suit the materials to be cut.