TECHNICAL INFORMATION NORTON WINTER PRECISION TECHNOLOGY TOOL GRINDING / 161 SPECIFICATION The specification is the general description of the grinding tool and contains all relevant information concerning the product‘s features. In general, the specification always contains the following details: SUPERABRASIVES Diamond and cubic boron nitride are the hardest materials existing in industry today, according to the current state of knowledge. The levels of hardness of diamond and cBN are significantly higher than those of conventional abrasives like alumina (corundum) and silicon carbide (see hardness). WEAR EFFECTS ON DIAMOND AND CBN The hardness of an abrasive grit type alone is not sufficient to determine the grinding tool‘s grinding behaviour. Diamond and cBN grains can wear in many ways, causing different effects. Primarily, there are two main types of wear. MECHANICAL WEAR: Abrasion, micro-chipping of cutting edges, grit macrofracture, and breakout of grain from the bond. CHEMICAL AND THERMAL WEAR Carbon diffusion, graphitization, oxidation, and reaction with grinding fluids. Diamond not only reacts with iron (above a certain threshold temperature), but also with chromium, vanadium and tungsten. cBN does not show chemical reaction with iron or other metals. Therefore, cBN has proven to give better tool performance when machining, for example, high speed steel, although it is not as hard as diamond. An outward sign of the occurance of thermo-chemical wear is the rapid appearance of wear flats on the grains, when no grain chipping from mechanical wear is present. EXAMPLE: 11V9 100-2-10-20 D126 K+888R C75 A Shape Dimension Grit Size Bond Concentration Body Furthermore, the specification can contain additional information regarding drawing index, production method, structure, and other details.
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