Talking about the development and application of tool coating technology (3)

Application of new PVD coating technology in super-hard material coating

The Department of Physics of Wuhan University uses DC reactive magnetron sputtering to deposit a carbon nitride (CxNy) super-hard coating film on the surface of the tool. The thickness is only a few microns and the hardness can reach 40~50GPa. The CxNy coated tool can cut black and Non-ferrous metals.

Experimental data

The author has conducted long-term research on the cutting performance of coated high-speed steel and cemented carbide tools (blades), and carried out many scientific experiments. I will introduce some experimental data as follows:

1 Under the same cutting conditions, the service life of the coated tool insert is 3 to 5 times higher than that of the uncoated tool (blade). Under the same cutting conditions, the cutting speed of the coated tool is 20~30% higher than that of the uncoated tool under the same tool life.

2 Under the same cutting conditions, the cutting tool (blade) has a lower cutting force than the uncoated one. Compared with uncoated blades, the main cutting force Fc can be reduced by 3%~4%, and the Fc of TiN or TiC/TiN coated blades can be reduced by 6%. Feed force is compared with uncoated blades. The decrease in Ff and depth of cut Fp is particularly significant. The Al2O3 coated insert and cutting force reduction effect is close to that of the TiN coated insert.

3 I have used CVD coated diamond thick film cutter to process silicon aluminum alloy, various hard aluminum, lead brass, oxygen-free copper, titanium iodide and fiber reinforced and particle reinforced composite materials, etc., have achieved good results. . But the tool used for ultra-precision cutting is not as effective as natural diamond tools.

4 I have used CxNy coated high-speed steel drill bits to drill holes in high-strength steel. Compared with uncoated drill bits, the service life of coated drill bits is increased by 7~9 times. Coating CxNy on other high speed steel tools also has a significant effect. CxNy has been applied to cemented carbide inserts to turn steel, and the effect is not satisfactory. Its service life does not exceed that of ordinary TiC coated carbide inserts.

China's tool coating technology is still far from the developed countries. The number of coated tools is also very far, accounting for only 20% of all tools. Among them, CNC machine tools and machining centers use much more. On the ordinary non-CNC machine tools, there are few pitiful reasons, such as understanding problems and prices. We should strive to improve the level of tool coating technology and application technology, and promote the application of coated tools to promote the improvement of cutting and mechanical manufacturing.

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