The coated cutting tools occupy a place in the category of CNC tools for CNC machining. The performance of the cutting tool can be improved by coating the cutting tool. The coated tools make a great breakthrough in cutting performance. Coated cutting tool refers to coating one or more layers of refractory compound with good wear resistance on the tool body with good toughness, which greatly improves the performance of the tool by combining the tool matrix and hardness. Coated tools can improve machining efficiency, improve machining accuracy, prolong tool life and reduce machining cost. Coated CNC tools account for about 80% of the cutting tools, and will become an important tool variety of CNC tools.
1. According to different coating methods, the coating tools for CNC machining can be divided into coating tools with chemical vapor deposition and coating tools with physical vapor deposition. The coating cemented carbide tool usually adopts chemical vapor deposition method, and the deposition temperature is about 1000 ℃. The high speed steel tool with coating usually uses physical vapor deposition method, and the deposition temperature is about 500 ℃.
2. According to the different substrate materials of coated tools, cutting tools coating can be divided into carbide coated tools, high-speed steel coated tools, coating tools on ceramics and superhard materials.
3. According to the properties of coating materials, the coating tool can be divided into “hard” coated tool and “soft” coating tool. The “hard” coating tool mainly pursues high hardness and wear resistance, and its advantages are high hardness and good wear resistance, typical of which are tic and tin coating. The goal of “soft” coating tool is low friction coefficient, that is, self lubricating tool, and the friction coefficient of workpiece material is only about 0.1, which can reduce the adhesion and friction, reduce cutting force and cutting temperature.
4. Recently, nano coated tools have been developed. The coating tool can be used with different combinations of various coating materials to meet different functional and performance requirements. The design of the nano coating can make the tool material have excellent anti friction and anti-wear function and self-lubricating performance, and is suitable for high-speed dry cutting.
1. Good mechanical and cutting performance: The CNC coated cutting tool combines the excellent performance of the substrate material and the coating material, which not only maintains the good toughness and high strength of the substrate, but also has the high hardness, high wear resistance and low friction coefficient of the coating. Therefore, the cutting speed of the coated tool is 2 times higher than that of the uncoated tool, and a higher feed rate is allowed. The life of coated cutting tools is also improved.
2. Strong universality: The coated tools in CNC tools have wide universality and wide processing range. One kind of coated tools can replace several kinds of uncoated tools.
3. Coating thickness: With the increase of coating thickness, the tool life also increases. When the coating thickness reaches saturation, the tool life will not increase any more. When the coating is too thick, it is easy to peel off, and when the coating is too thin, the wear resistance is poor.
4. Regrinding property: The regrinding property of coated blade is poor, the coating equipment is complex, the process requirement is high and the coating time is long.
5. Coating materials: The cutting performance of tools with different coating materials is also different. When cutting at low speed, TiC coating has the advantage; when cutting at high speed, tin is more suitable.
The CNC coated tools have great potential in the field of CNC machining, and will be a very important tool variety in the field of CNC machining in the future. Coating technology has been applied to end mills, reamers, drills, composite hole machining tools, and gears. Hobs, gear shaping cutters, gear shaving cutters, forming broaches and various machine-clamped indexable inserts can meet the needs of high-speed machining of various steel and cast iron, heat-resistant alloys and non-ferrous metals.