The wheel is the main abrasive grinding. The wheel is in the added binding agents, a porous body made by the green compacts, drying and firing the abrasive. Abrasive, bond and manufacturing processes, grinding wheel characteristics vary widely, so grinding machining quality, cutting wheel,productivity and economy. The characteristics of the grinding wheel is mainly determined by the abrasive strength, binding agents, hardness, organization, shape, and size and other factors.
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The grinding wheel wide variety. The ordinary abrasive (corundum and silicon carbide) Wheel and natural abrasive superhard abrasive (diamond and cubic grinding wheel used abrasive can be divided into
Boron nitride) grinding wheels; binder can be divided into ceramic grinding wheel, resin grinding wheel, rubber wheel, metal grinding wheel shape can be divided into level grinding wheels, bevel grinding wheel, cylindrical grinding wheel, cup wheel, disc wheel; . The characteristic parameter of the wheel main abrasive, viscosity, hardness,grinding wheel, binding agent, shape, size and so on. Due to the grinding wheel usually work at high speed, and thus should be carried out before use rotation test (to ensure that the wheel at the highest speed, not broken) and static balance test (to prevent work caused by machine vibration). Grinding wheel after working for a period of time should be trimmed in order to restore the grinding performance and correct geometry.

file belt    (Photon belt), also known as the photon ring, is derived from the contents of faith in the New Age movement. The belief that the solar system revolves around the Pleiades, and the vertical plane of the solar system orbit around the rich presence of high-energy photon-photon belt. Legend of December 22, 2012, the Earth will be completely enters the photon belt, when the sun and the stars will disappear from view, causing up to 2 to 3 days of the polar day or the polar night, the earth's electromagnetic field will collapse, all the atoms will be changed , survival of the human spirit to enhance the ability to get a wide range of human into the "photon era." However, the above phenomenon did not happen, in fact it is not the solar system revolves around the Pleiades, but there is no reliable scientific literature or astronomical observation records show that these objects exist. Photonic band doctrine is not recognized by the international scientific community.