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The technological ability of modern gear grinder can strengthen the amount of quenching gear. However, the potential productivity has not been utilized due to the surface defects produced when grinding teeth with ordinary abrasive tools. The tempering strength of the inner gear is reduced by 40% and the tempering strength of the worn gear surface is reduced by 40%.
When grinding with ordinary abrasive tools, the grinding heat intensity can be reduced by using the abrasive tools with intermittent working surfaces. However, the cutting ability of corundum abrasive grains is relatively low, which may lead to burns, thus reducing the wear resistance of gears and the labor productivity in gear grinding.
All this leads to the need to replace corundum abrasives with more perfect tool materials that can guarantee effective machining of carburized and quenched alloy steel; cubic boron nitride with high thermal stability and chemical inertness is such material.
CBN Abrasives can be coated with metal to improve the grinding effect. However, metal coated CBN Abrasives can not be used for grinding without coolant, because the presence of metal in the abrasive working layer promotes the increase of temperature and the formation of burn in the grinding zone.
In order to improve the ability of cubic boron nitride abrasive in non cooling grinding, the former Institute of superhard materials of Ukrainian Academy of Sciences has developed a method of non-metallic coating on the abrasive grains. This method improves the strength of the binder holding the abrasive particles without increasing the temperature in the cutting zone.