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Grinding wheels are also called fixed abrasive tools. The grinding wheel is a fixed shape (mostly round, with through holes in the center) of ordinary abrasives that are consolidated by a bonding agent and has a certain strength. It is generally composed of abrasives, binders and pores. These three parts are often referred to as the three elements of a consolidated abrasive. According to the different classification of the bonding agent, the common ones are ceramic (bonding) grinding wheels, resin (bonding) grinding wheels, and rubber (bonding) grinding wheels. Grinding wheel is one of the largest amount of abrasive tools and the widest range of use. It rotates at high speed when used, and can rough and semi-finish the outer circle, inner circle, flat surface and various profiles of metal or non-metal workpieces. And fine grinding, grooving and cutting, etc. Grinding wheels are the most important type of abrasive tools in grinding. The grinding wheel is a porous body made by adding a binder to the abrasive, and then forming a compact, drying and roasting. Due to the different abrasives, bonding agents and manufacturing processes, the characteristics of the grinding wheels are very different, which has an important impact on the quality of grinding, productivity and economy. The characteristics of the grinding wheel are mainly determined by factors such as abrasive, particle size, bonding agent, hardness, organization, shape and size. There are many kinds of grinding wheels. According to the abrasives used, it can be divided into ordinary abrasives (corundum and silicon carbide, etc.) grinding wheels, natural abrasive super-hard abrasives and (diamond and cubic boron nitride, etc.) grinding wheels; according to the shape, it can be divided into flat grinding wheels, beveled grinding wheels, cylindrical grinding wheels, Cup-shaped grinding wheels, dish-shaped grinding wheels, etc.; according to the bonding agent can be divided into ceramic grinding wheels, resin grinding wheels, rubber grinding wheels, metal grinding wheels, etc. The characteristic parameters of the grinding wheel mainly include abrasive, particle size, hardness, bonding agent, shape, size and so on. Since the grinding wheel usually works at high speed, it is necessary to carry out a rotation test (to ensure that the grinding wheel will not break at the working speed) and a static balance test (to prevent vibration of the machine tool during work) before use. After working for a period of time, the grinding wheel should be trimmed to restore the grinding performance and correct geometry.