The precision grinding industry is a vast and complex environment, that demands premium grinding media to deliver optimum performance and results. With a range of different applications that require unique and specific results, several wheel shape derivatives are available.

Apart from the shape 1 straight wheel, used for conventional grinding applications, grinding wheels come in a range of other shapes and sizes including the well-known cup wheels.

Cup wheels can range from either a shape 6, which refers to a straight cup, shape 11, commonly known as a “flared” cup wheel, or type 2, which resembles a cup wheel with a ring shape – all very popular for grinding applications in industries, like toolroom, automotive, aircraft, engine components and wood working manufacturing.

Used for either producing new components, or regrinding and/or resharpening of the different components after becoming blunt due to use, typical tools ground with shape 6, 11 and 12 cup wheels, include broaches, cutters, millers, reamers, drills, taps, and dies.

Most cup wheels are used for applications on fixed mechanical tool and cutter grinding machines, ranging in diameter size from 50mm up to 150mm, with a thickness starting from 10mm going up to 80mm.

Shape 6 and 11 cup wheels are usually manufactured with rim widths ranging from 4mm up to 13mm and are mainly manufactured with a vitrified bond, containing either aluminium oxide or ceramic grains.

Choosing the appropriate grain when cup wheels are manufactured requires careful consideration of the material being ground, desired results as well as the amount of stock removal required.

During precision grinding applications, burning of the workpiece, is often a common challenge, which can be overcome by either using coolant during the application, or making use of a dressing application which can reduce, or eliminate this problem.

By creating chamfer on the rim with a handheld dressing stick, the cup wheel’s width will be thinned out, which will effectively decrease the contact surface area of the cup wheel to the workpiece, eliminating burn during application.

For grinding applications where a workpiece contains some heat sensitive materials, the use of a coolant during application should be considered as to minimise burning of the workpiece. In cases where workpieces consist only of heat sensitive metals, cup wheels manufactured from ceramic grains should be considered due to its cool grinding properties.

Apart from delivering reduced heat during grinding applications, ceramic grains are the most technologically advanced, offering self-sharpening properties with excellent stock removal in the shortest possible time. Effectively, this reduces overall downtime, as more components can be ground in between dressing applications, which, in the long run, not only reduces overall labour costs, but electricity, machine wear and tear, as well as consumable costs.

Also used in the manufacturing of cup grinding wheels, known as the purest grain, is white aluminium oxide, which with its high friability, is suitable for grinding heat sensitive steels, delivering optimum stock removal during application, without causing burn to the workpiece.

When it comes to applications on cemented carbide parts, green silicon carbide grain will be the prerequisite, as it possesses both the extremely sharp grain characteristics, as well as the sought-after friable properties. Grinding wheels manufactured from Green Silicon Carbide usually range in grit sizes of 46 to 220, with a hardness grade ranging from H to N.

When manufacturing these wheels, the combination of grain and hardness are determined by the hardness of the workpiece to be ground, as well as the type of grinding application and required finish.

Grinding Techniques have been manufacturing Andor precision grinding abrasives locally since 1981 and specialise in custom grinding application solutions.

Whatever your abrasive requirement, our application specialists are ready and available to analyse your requirement and propose a cost-effective solution.

For further information contact Grinding Techniques on TEL: 011 271 6400 or email info@grindtech.com or visit www.grindtech.com