Coating tool has become a symbol of modern cutting tools, which has exceeded 50% usage to improve their working performance. , including drill bits, reamers, taps, milling cutters, forming tools, etc.
As a chemical and thermal barrier, the coating reduces the diffusion and chemical reactions between the tool and the workpiece, thereby reducing the wear of the substrate. The coating tool has a high surface hardness, good wear resistance, stable chemical resistance, heat resistance, low friction coefficient and low thermal conductivity. It can also increase the life by more than 3~5 times than uncoated tools during cutting. Increasing cutting speed by 20%~70%, machining accuracy by 0.5~1 level, and reduce tool consumption costs by 20%~50%.
At present, the common coating types in the industry are divided into the following 5 types.
1. Titanium nitride coating (TiN)
TiN is a general-purpose PVD coating that can improve tool hardness and has a higher oxidation temperature.
The coating can be used for high-speed steel cutting tools or forming tools to obtain very good processing results.
2. Titanium Carbide Nitrogen Coating (TiCN)
The carbon element added to the TiCN coating can increase the hardness of the tool and obtain better surface lubricity. It is an ideal coating for high-speed steel tools.
3. Nitrogen-aluminum-titanium or nitrogen-titanium-aluminum coating (TiAlN/AlTiN)
The aluminum oxide layer formed in the TiAlN/AlTiN coating can effectively improve the high temperature machining life of the tool. Cemented carbide tools mainly used for dry or semi-dry cutting. According to the ratio of aluminum to titanium in the coating, AlTiN coating can provide higher surface hardness than TiAlN coating, so it is another feasible coating choice in the field of high-speed processing.
4. Chromium nitride coating (CrN)
The good anti-adhesion of CrN coating makes it the first choice in the processing that easily produces built-up edge. After coating this almost invisible coating, the processing performance of high-speed steel cutting tools or cemented carbide end mills and forming tools will be greatly improved.
5. Diamond coating (Diamond)
CVD diamond coating can provide the best performance for processing tools of non-ferrous metal materials. It is an ideal coating for processing graphite, metal matrix composites (MMC), high silicon aluminum alloys and many other highly abrasive materials.
The coatings suitable for hard milling, tapping and drilling are different and have their own specific application occasions. In addition, multi-layer coatings can also be used. This type of coating also has other coatings embedded between the surface layer and the tool base, which can further improve the service life of the cnc milling tools.