Tool Coating Materials And Coated Tool Applications

Machinery manufacturing,one of the most important components of manufacturing,bears the mission to provide machineries and equipments for each department of the national economy.The pace of modernization of our country depends mainly on the development of machinery manufacturing industry.Therefore,from this sense,the machinery manufacturing industry is related to the development of the country.Among the ways of Machinery Manufacturing processing,material removal processing has been widely used because of its high precision,better surface quality and intense self-adapting.Material removal processing can be divided into cutting processing and some special processing.Cutting processing,which is to cut the extra material from the workpiece with tools, requires the hardness of cutting tools much higher than the workpiece.The performance of cutting tools depends on the material of the tools,the geometry parameters of the cutting part and the structure of the tool.Currently the main material utilized in the production of cutting tools is high-speed steel and hard alloy.High-speed steel is of high strength and good toughness,but the hardness and wear resistance are worse than hard alloy;hard alloy is of good hardness and wear resistance,but the strength and toughness are worse than the high-speed steel.The coating tool,the substrate of high-speed steel or hard alloy coated with a layer of refractory metal compounds,is of hard surface, good wear resistance and its matrix has good bending strength and toughness.The lifetime of coated hard alloy Tool can be increased by 1～3 times,while Coated High-speed Tool can be increased from 1.5 to 10 times.Coated cutting tool can do dry cutting,that is,without of cutting fluid in processing, thereby can save resources,save material,reduce energy consumption,drain contamination,and pollution to the surrounding and achieve the friendly Machining process.Dry-type processing,high demanding of the material of tool,requires materials to be of high red hardness and toughness of hot, good wear resistance,thermal shock and anti-caking.Now,super-hard materials such as Cube Boron Nitride(CBN),polycrystalline diamond(PCD) and ultra-fine grained cemented carbide have been widely used in dry cutting.The experimental results show that the ideal condition of dry cutting is high-speed cutting,which can reduce the spread of the heat on the workpieces,tools and machine tools. Many studies reveal that high-speed steel and cemented carbide coated by PVD,CVD can also be used in dry cutting,and are much cheaper than super-hard materials such as Cube Boron Nitride(CBN), polycrystalline diamond(PCD) and ultra-fine grained cemented carbide.The experimental results show that in the processing of Al-Si alloy and hardened steel,the coated tool has a longer lifetime than the uncoated one.In this paper,from the cutting experiment we find that it is feed rate that affects the surface roughness of parts under high-speed dry cutting conditions.The aim is to find out the suitable parameters for cuttings from the experiments based on the surface quality of the processing.