Practically any cutting-off application can be performed by a new generation of medium and large diameter, reinforced cut-off wheels introduced by Saint-Gobain Abrasives under its NORTON brand, the world's leading supplier of bonded abrasives. Called TOROS™, the wheels are available in diameters up to 1.8 metres and are intended for automatic or semi-automatic cutting on static machines, but not freehand use.

Target markets for the durable products, which are now the premium options in the supplier's portfolio of cut-off wheels, range from steel production plants and foundries through vehicle manufacture and aerospace alloy production to preparation of samples for laboratories and test facilities.

A fast, cost effective and versatile alternative to bandsawing, the wheels are available in a vast array of abrasive / bond specifications. Permutations are available for cutting most metals, from copper alloys to stainless steel and titanium slab, billet, bar and tube, of large or small cross section, at any temperature up to 1,000 °C.

The wheels are equally adaptable when it comes to the mode of cutting, whether it is chop stroke, orbital, traverse or oscillation. Products can be selected for wet or dry cutting and may be used productively on new, high horsepower equipment as well as on older, lower power, chop stroke machines. Long life is claimed for the free-cutting wheels, together with high G-ratios (material removed / wheel wear), less burning, clean cut surfaces and no burrs.

TOROS™ wheels are strengthened across the entire diameter of the wheel. The construction ensures maximum safety at elevated rotational speeds as well as high resistance to lateral stresses and breakage, even when the wheel snags. The costs of early wheel replacement and perhaps also of scrapped components are therefore saved.

Abrasive wheel cutting versus bandsawing

Looking specifically at the comparison between using an abrasive wheel or a bandsaw blade for cutting metal, the first point to make is that the latter 'tool' requires higher capital outlay on the machine, particularly if it is of extra-rigid design for running blades with tungsten carbide tipped (TCT) teeth.

The bandsawing consumable itself is more expensive than a TOROS™ wheel by between 20 and 300 per cent, depending on wheel size and specification, and on whether a TCT or conventional bimetal blade is used.

Most importantly, productivity is significantly higher with a TOROS™ wheel. A cut that would take 7 to 10 minutes on a bandsaw requires typically 2 to 3 minutes using one of the new cut-off wheels. Downtime is also reduced, as it is much faster to fit a new wheel than to exchange a bandsaw blade.

Wide range

Eight categories of wheel provide different cutting characteristics, based on various blends of alumina, zirconia oxide and silicon carbide abrasive grains. Thirteen different grades from 16 to 60 grit are contained in one of four bond types that are specifically designed for high abrasive grain retention.

The wheels are supplied in a wide range of diameters and thicknesses and in straight, tapered and depressed centre variants. All wheel sides are abrasive, the roughness ensuring maximum cut rate. Additional drive holes can be added on request.

It is the ability of Saint-Gobain Abrasives to offer such a breadth of choice that allows users to select a standard product that very closely matches the intended application. The manufacturer also offers bespoke wheel production for larger users and will tailor the TOROS™ wheel composition to customers' specific requirements.

Process optimisation

The best production solution for any given application is identified by Saint-Gobain Abrasives on the basis of a Process Solutions Program (PSP), a free service to customers whereby it undertakes to help them maximise competitive advantage when using its products.

Dedicated engineers visit to analyse a user's operations holistically and map the performance of the production process, taking into account the machine, material to be machined and wheel. This leads to an informed selection of the best grinding process parameters to maximise productivity, improve quality and lower production costs. Reducing both cycle times and wheel change frequency raises productivity and machine utilisation, cutting manufacturing cost per part, so it is on these areas that PSP analyses are mainly focused.

Quality enhancement and scrap reduction impact heavily on the bottom line and are similarly targeted. Other factors addressed include vibration control and optimisation of feeds and speeds. A safety audit also forms part of the overall assessment.

All Saint-Gobain Abrasives products, including TOROS™ cut-off wheels, are manufactured in accordance to ISO9001 as well as EN12413 safety requirements for bonded abrasive products. They also meet oSa (Organisation for the Safety of Abrasives) standards governing the quality of abrasive products and management of the processes for their manufacture. Saint-Gobain Abrasives is an active member of FEPA, the Federation of European Producers of Abrasives.