Abrasives
        Abrasive is in use process, when the abrasive grinding blunt, due to the particle part of their break-up and bond rupture abrasive, grinding particle from the abrasive on the partial or complete loss, and abrasive abrasive working surface of the emerging new cutting edge, or constantly exposing new sharp abrasive, the abrasive in a certain period of time to keep the cutting performance. This kind of self sharpening abrasive tool is a prominent feature of the abrasive tool and general tool. Abrasive early in the Neolithic age, humans have already begun application of natural stone processing stone knives, axes, bone, horn and dental tools; in the 18th century, the United States appeared to use a combination of natural abrasive and clay kiln ceramic grinding wheel; 180 years before and after the advent of artificial abrasives, using artificial Abrasives manufacturing various abrasive products have generated, for the rapid development of grinding and grinding machines created conditions. Since then, the proportion of natural abrasives in the abrasive gradually reduced. Abrasives according to their raw material sources, there are two types of natural and man-made abrasives. In the machinery industry commonly used only natural abrasives whetstone. Artificial abrasives according to the basic shape and structural characteristics of the distinction, a grinding head, grinding wheel, oilstone, sand tile above collectively bonded abrasivesand coating attached to five class. In addition, sometimes the abrasive agent as a kind of abrasive.