Executive Report:

Advances in abrasives

Dronco is typical of bonded abrasive manufacturers that have developed products to meet demands regarding application, performance and safety. Phil Mist reports.

Today, many types of resinoid bonded abrasives are manufactured using fully automatic processes and computer controlled techniques. To produce a wheel or disc takes 24-36 hours depending on type and size. Zirconium is added by one or two manufacturers to their wheels and discs, but modern products contain essentially the same raw materials as their predecessors, namely, a cutting material (either aluminium oxide or silicon carbide grit), fillers for bulking the mix out, phenolic resin for gluing everything together, and sheets of glass fibre for rigidity during use. Some modern resinoid wheels and discs may, however, contain materials free of iron, sulphur and chlorine to prevent contamination of the material being cut or ground, and the finished wheels may even be extremely thin to increase cutting rates.

The use of bonded abrasives in the construction industry has fallen steadily, in many cases having been replaced by diamond blades, which have become very price competitive. However, they are still used by small builders, amongst others, and therefore many tool hirers still stock them. To secure higher sales, manufacturers have introduced specialist discs and wheels to their ranges, rather than relying on the traditional 175mm (7in) depressed centre discs, 230mm x 3mm (9 x 1/8in) and 300mm x 3mm (12 x 1/8in) flat stone cutting wheels, once so popular in hire.

In the engineering industry, bonded abrasives are still used in large quantities, but the wheels used are much more performance related. Thin wheels abound, with flat products only 1mm or 1.2mm thick being used, often designed for cutting stainless steel or other fairly exotic materials. These are made under particularly strict quality control procedures.

One manufacturer of such wheels is German-based Dronco AG, whose UK arm, Dronco Abrasives UK, is in Manchester. Dronco produces more than 250,000 cutting and grinding wheels and discs every day. Special products, such as the company’s Freecut, which has a slightly conical shape to reduce the ‘pinching’ that occurs when cutting wheels are deeply embedded in raw materials, have now established themselves well in the market place.

Bonded abrasive wheels may often be stored for long periods in the warehouses of dealers or distributors, and this is also often true of some of the less popular sizes and types stocked by hire companies. Whilst bonded abrasives will certainly not become lethal overnight, the performance of old wheels does fall away dramatically. The operator will be bombarded with abrasive grit released from the product, which will obviously wear more rapidly. To eliminate this, Dronco has begun marking the metal insert of every one of its bonded abrasive wheels or discs with a ‘use by’ date. In addition, to increase the shelf life of its wheels, the manufacturer is now sealing some of its products in tins, so that they remain as fresh as when first manufactured, and which retain a high performance level, even though they may have been made weeks or months before they are actually used.

Dronco offers the hire industry a comprehensive range of bonded abrasive wheels and discs, as well as diamond blades, suitable for virtually every application, all made to high quality standards. However, it must be remembered that it is not just the quality of the product that is important. The power available from modern angle grinders has increased dramatically, and safe operation is quite literally in the hands of the user. Operators and fitters should, therefore, be thoroughly trained to ensure their safety and that of
any fellow workers nearby. •

T 0161 874 2600
W www.dronco.com

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