Features coated tools are as follows:      ① mechanics and cutting performance is good: coated tools and excellent material properties of the matrix of the coating material together, while maintaining the substrate good toughness and high strength, but also has a coating of high hardness, high wear resistance and low coefficient of friction. Therefore, the coating cutting tools than the uncoated tool can be increased by 2 times, and allows a higher feed rate. Coated tool life is also improved.      ② versatility: coated tools wide versatility, significantly expanded range of processing, a coated tool can replace the use of several types of non-coated tools.      ③ coating thickness: With the coating thickness increases tool life will increase, but when the coating thickness reaches saturation, increased significantly longer tool life. When the coating is too thick, easy to cause peeling; When the coating is too thin, poor wear resistance.      ④ regrinding: the coating blade resharpening poor coating equipment complex process requirements, long coating times.      ⑤ coating material: Tool different coating materials, cutting is not the same. Such as: low-speed cutting, TiC coatings advantage; during high-speed cutting, TiN more appropriate. Application of coated tools      Coated tools in CNC machining field has great potential, will be the next most important field of CNC machining tool varieties. Coating technology has been applied to mills, reamers, drills, complex processing tools, gear hobs, shaper cutters, shaving cutters, broaches and various molding machine folder indexable inserts to meet various high-speed machining kinds of steel and cast iron needs, heat-resistant alloys and non-ferrous metals and other materials.