Grinding is a processing method that scrapes off objects with a grinding wheel rotating at high speed. The grinding wheel consists of three elements (abrasive grains, binder, and pores), and the abrasive grains can act as a blade to cut very hard materials and improve surface accuracy. It is generally used for high-precision processing of molds for pressing and molding, as well as using in the most important parts of machinery. The machine tools is used to including surface grinders, cylindrical grinders, etc. There are also NC surface grinders and NC cylindrical grinders equipped with NC devices. Other types of machines include centerless grinders used for mass-production processing of pins, profile grinders used for fine profile processing, and jig grinders used for high-precision processing of holes.