Researches about Dressing of Vitrified Bond CBN Grinding Wheel

The excellent grinding performance of vitrified bond CBN grinding wheel is related to many grinding factors, such as grinding wheel characteristic parameters, grinding parameters, grinding fluid and the dressing method of grinding wheel. Among them, the grinding wheel dressing method plays a key role. If the grinding wheel is not well dressed, the ground metal will be bonded to the surface of the grinding wheel, resulting in large grinding force, high grinding temperature and increasing wear of the grinding wheel. The vitrified CBN grinding wheels should be trimmed at high speed with cup shaped diamond wheels. Generally, single-grain diamond or diamond pen trimming is used, and silicon carbide grinding wheel is also used to trim vitrified bond CBN grinding wheel. Although it is easier to implement a ceramic CBN grinding wheel with single diamond, there are many problems.
Due to the high hardness of the grinding wheel itself, the single diamond is easily passivated compared with the dressing of the ordinary grinding wheel, so that the surface condition of the obtained grinding wheel is not good, resulting in large grinding force in the initial grinding stage, high grinding temperature, and fast abrasion of the grinding wheels. In addition, the grinding wheel is easily bonded by the grinding material. Experimental studies have shown that the abrasive grains on the ceramic CBN grinding wheel trimmed with single diamond are not sharp, and the material to be ground is easily bonded to the top of the abrasive grain during grinding process.
When the vitrified bond CBN grinding wheel is trimmed with the silicon carbide dressing wheel, the grinding wheel can be dressed and sharpened at the same time. In order to achieve the purpose of sharpening, the granularity of the dressing wheel should be finer. The grinding state of the surface of the ceramic CBN grinding wheel trimmed by the silicon carbide dressing wheel is sharp.
The grinding stone method is a very simple sharpening method for ceramic CBN wheel. During trimming, the ceramic CBN grinding wheel is first trimmed with a diamond trimming pen, and then the ceramic stone is ground with a ceramic CBN grinding wheel to achieve a certain amount of convexity and a sharp sharpening edge. When the ceramic CBN grinding wheel is trimmed by this method, the size of the oil stone has little effect on the trimming effect.
When the single-grain diamond is used to dress ceramic CBN grinding wheel, the abrasive surface of the finished grinding wheel is passivated due to the rapid wear of the diamond, so the initial grinding force and the grinding temperature are both large. And the initial wear amount of the grinding wheel is also large. Therefore, although the ceramic CBN grinding wheel can be trimmed with a single diamond, the excellent grinding performance of the ceramic CBN grinding wheel cannot be fully exerted. Dressing the vitrified CBN grinding wheel with the silicon carbide grinding wheel or grinding the oil stone method can solve the problem of large initial grinding force and high grinding temperature, and the surface condition of the grinding wheel will be improved. Therefore, in order to give full play to the excellent grinding performance of ceramic CBN grinding wheels, a reasonable grinding wheel dressing method must be selected.

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