Diamond and boron nitride tools - joke Technology GmbH - #3

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300 3 i Tel. +49 (0) 22 04 / 8 39-0 • Fax +49 (0) 22 04 / 8 39-61 • info@joke.de 3. Diamond and boron nitride tools Diamond and Boron nitride tools Interesting facts Diamond and Boron nitride tools are available in galvanic, resin, metal or the new vacuum brazed bonding Galvanic bonding With this type of bonding, the diamond or boron nitride grain is bonded to the carrier by galvanisation. The bonding is applied in layers, whose thickness is dependent on the Grit size. In special cases, however, several layers may be applied. In this bonding, the abrasive grits project to a relatively high degree from the bonding. These tools are highly effective and allow high cutting rates. This bonding allows economical and rapid manufacture of special tools. Recoating of the worn tool is possible. Applications Tungsten carbide and tungsten carbide green compact, glass-fibre reinforced plastics, fibre-reinforced, duroplastics and thermoplastics, electrocarbon, ferrite, graphite, glass, rubber (diamond), high-speed steel, hardened steel, high alloy steels (boron nitride). Cutting speed: Approximately 20 - 60 m/s Resin bonding In resin bonding, the diamond or boron nitride grain is densely compressed over the entire coating. Synthetic materials with different properties are used as binders. The quantity of grains distributed over the abrasive coating is dependent on the concentration. This bonding is characterised by a low grinding temperature and high stock removal. It has established itself for tool grinding applications. It allows a high surface quality to be obtained. Concentration C50 and C75 as standard Applications Tungsten carbide (diamond), high-speed steel, tool steel (boron nitride). Cutting speed: Approximately 10 - 40 m/s Metal bonding The abrasive coating in this type of bonding consists of a mixture of metal powder and diamond or boron nitride grit. Grinding tools with metal bonding are manufactured by sintering. The high degree of hardness of the metal bonding renders the grinding wheel very resistant to wear, but is not as effective as the other bonding systems. Concentration C100 as standard Applications Ceramic materials, glass, profile grinding of tungsten carbide, ferrite (diamond). Cutting speed: Approximately 10 - 30 m/s Vacuum brazed bonding NEW! With this bonding type, the abrasive grits are directly fused with the carrier. The adhesion of the grits can thus be greatly improved. The grain protrusion results in a very high removal rate. Applications These tools are particularly suited for glass fibre-reinforced materials and carbon-fibre reinforced plastic (in aircraft construction and coarse fine shipbuilding), tungsten carbide green compact (unsintered tungsten carbide), ceramics (i.e. valve covers for car engines), coal products (i.e. brake discs, carbon brushes) and cast materials. Cutting speed: Approximately 20 - 40 m/s Diamond and boron nitride abrasives Diamond and boron nitride are the hardest abrasives in the world. They are far harder in comparison to conventional abrasives such as corundum and silicon carbide. Diamonds exist in natural and synthetic form. Boron nitride exists only in synthetic form. Diamonds are made of carbon and are excellent for grinding short-chipping materials. Owing to the fact that the carbon in diamond is incompatible with the carbon contained in steel, diamonds are unsuitable for steel processing. Diamond consists of carbon and is perfectly suited for grinding short-chipping materials. Because of an incompatibility of diamond carbon with the carbon in steel, diamond cannot be used for steel machining. Boron nitride contains no carbon and is optimally suitable for grinding different types of steel. The high level of hardness of diamond and boron nitride presents a number of advantages, such as a long service life, precise reproduction of shape and exact dimensions during the machining process. Grits FEPA standard U. S. Standard mesh Grit size (micron) tight loose tight loose D 1181 D 1182 16/18 16/20 1180-1000 D 1001 18/20 1000-850 D 851 D 852 20/25 20/30 850-710 D 711 25/30 710-600 D 601 D 602 30/35 30/40 600-500 D 501 35/40 500-425 D 426 D 427 40/45 40/50 425-355 D/B 356 45/50 355-300 D/B 301 50/60 300-250 D/B 251 D/B 252 60/70 60/80 250-212 D/B 213 70/80 212-180 D/B 181 80/100 180-150 D/B 151 100/120 150-125 D/B 126 120/140 125-106 D/B 107 140/170 106-90 D/B 91 170/200 90-75 D/B 76 200/230 75-63 D/B 64 230/270 63-53 D/B 54 270/325 53-45 D/B 46 325/400 45-38