Cutting tools are widely used in industrial processes. Now that the level of the machining industry is increasing, the industry has put forward new requirements for cutting tools. In addition to the improvement of technological level, sustainable development of green environmental protection has become a new trend.

In addition to increasing the service life of the current tool products, it is also required to reduce the contamination during cutting and use dry cutting as much as possible. When the cutting fluid cannot be completely eliminated, try to make it contain only anti-rust agent and no organic matter, which can greatly reduce the cost of recycling.

The variety of cutting tools and the operating state characteristics during use determine the choice of tool coating. Different from turning and drilling, milling cutters should also consider the characteristics of intermittent impact. The early development of the coating is mainly focused on wear resistance, in order to increase the hardness as the main indicator. Such coatings represented by titanium nitride have a high coefficient of friction, and constant friction between the workpiece and the workpiece will generate a large amount of thermal energy.

In order to avoid tool deformation caused by overheating affecting machining accuracy and extending its service life, cutting fluids are usually used. To solve the problem of reducing or eliminating the cutting fluid, the tool coating should not only allow the tool to have a long life, but also have a self-lubricating function. The appearance of diamond-like coatings has shown advantages in mechanical processing of certain materials, but after years of research shows that the DLC coating has high internal stress, poor thermal stability, and the catalytic effect with ferrous metals makes SP3 structure to SP2. The three shortcomings, such as shifting, determine that it can currently only be applied to the processing of non-ferrous metals, thus limiting its further application in machining.

However, recent studies have shown that the hardness of diamond-like coatings mainly composed of SP2 can reach 20-40 GPa, but there is no problem with ferrous metal as a catalyst, and its friction coefficient is very low and it has good moisture resistance. The coolant can also be used for dry cutting, and its service life is improved by several times compared with the non-plating knife. There is no problem in processing steel materials, which has caused great interest for coating companies and tool manufacturers. In time, this new type of diamond-like coating will be widely used in the field of cutting.