3M explains Cubitron II grit technology

3M's Cubitron II is used in grinding wheels, fibre discs and abrasive belts, used principally in support of manual operations. Cubitron II, and the precision-shaped grain technology on which it is based, represents a new era. It is, says the company, changing cutting efficiency by moving traditional coated abrasives closer to machine tools, in terms of metalcutting dynamics, and promises to provide the platform for further developments for years to come. Image: Cubitron II grinding discs Image: Cut-off wheels Its similar name predecessor, Cubitron abrasive grain, was introduced in 1981. This was based around an extremely hard, sharp and tough ceramic aluminium oxide grain held within a uniformly crystalline structure. This new class of grain relied on controlling the ceramic body microstructure, with this improving the crushing behaviour of the bulk ceramic. Effectively, the grains develop micro-fractures during grinding which, as they break up, constantly expose fresh abrasives to the surface, resulting in faster cut rates. The use of this technology rapidly became the norm in applications involving medium stock removal. The development that laid the foundation for the most recent and, says 3M, potentially the most influential innovation in abrasives technology from the company, occurred in the 1990s, when further improvements were made to consistency. Abrasive products had previously used randomly arranged minerals that often delivered an inconsistent finish, but, with the development of Trizact, 3M moved into the area of microreplication technology. Unlike conventional ceramic grain, Trizact grain is in the form of a three-dimensional pyramid, with these grains uniformly arranged across the product surface. Each grain contains multiple layers of abrasive, with new layers exposed as the pyramids wear down. The benefits of this technology include a consistent, predictable finish; an even cut rate and longer product life. It was this advancement that formed the basis for the development of precision-shaped grain found in Cubitron II products, with these offering a fresh perspective on the grinding process and representing a significant breakthrough in abrasives technology, 3M highlights. Cubitron II is based on the ability to produce a precision-shaped ceramic grain, with the influence of the grain geometry being a significant factor. Precision-shaped grain is a precisely shaped, uniformly sized and vertically-orientated triangle of ceramic abrasive. The self-sharpening triangles fracture as they wear, to form new, super-sharp points and edges that slice cleanly through metal, delivering a much faster cut rate and higher quality performance. Image: Cubitron II is based on the ability to produce a precision-shaped ceramic grain Studying the mechanism for metal grinding and chip formation was one of the keys in understanding why Cubitron II products outperform products based on conventional crushed ceramic grain. The most efficient way to remove metal is with long, continuous metal chips, but, because of the variations in grain distribution and mineral sharpness of conventional ceramic chip, the action of the cutting tip is to 'plough' or gouge the surface of the material being worked. This reduces the efficiency of the cutting process by causing high frictional force, leading to heat build-up in the substrate. The precision-shaped grain contained in Cubitron II products, on the other hand, slices through metal, resulting in a more efficient chip formation and metal removal, while greatly reducing the head-related part damage. The Cubitron II range from 3M made its debut in the UK in 2010 and the range now includes grinding wheels, fibre discs and abrasive belts. A major advance in abrasives technology, they have proved to deliver extremely high performances on an extensive range of materials and across a wide range of industries. Compared with conventional products, they offer considerable practical and financial benefits, performing more efficiently, delivering higher quality finishes and lasting considerably longer – tests have shown that the new grinding wheels achieve significantly increased output compared with conventional products. Another key advantage of Cubitron II products is the reduced grinding force required during operation, compared with traditional grinding wheels. Allied with the fact that Cubitron II grinding wheels achieving greater output compared with conventional products, this can significantly reduce the potential impact that grinding operations can have on workers, particularly in terms of health issues such as hand-arm vibration, by reducing the time required and pressure needed to perform grinding operations.