Carbide end mills are also called cemented carbide end mill. The hardness of the tool itself is generally between HRA88-96 degrees, but the surface coating can extend the service life and performance of the end mill.
The coating acts as a chemical and thermal barrier, reducing the diffusion and chemical reaction between the tool and the workpiece, thereby reducing the wear of the substrate.
Compared with ordinary end mills, coated tools have high surface hardness, good wear resistance, stable chemical resistance, heat resistance, low friction coefficient, and low thermal conductivity. During cutting, its service life is more than 3 to 5 times higher than that of uncoated ones, the cutting speed is 20% to 70% higher, the processing accuracy is 0.5 to 1 level higher, and the tool consumption cost is reduced by 20% to 50%.
At present, the common tool coating types in the industry are divided into the following 5 types.
1. Titanium nitride coating (TiN)
TiN is a general PVD coating with a light yellow color. The coating can increase the hardness of the end mill and improve the wear resistance.
This coating can be used for high-speed steel, stainless steel or cast iron cutting tools or forming tools, and can obtain very good processing results.
2. Titanium carbide nitrogen coating (TiCN)
TiCN coating has strong adhesion and is blue-gray in color. The added carbon element can increase the hardness of the end mill and obtain better surface lubricity; at the same time, the application of this coating can also improve the toughness of the tool and increase the anti-oxidation performance, making it 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 increase the service life of the tool under high-temperature processing because the thermal conductivity of this coating is low. Therefore, the end mill using this coating has high heat resistance and can maintain high hardness at high temperatures.
According to the aluminum-titanium ratio in the coating, the AlTiN coating has a higher surface hardness than the TiAlN coating, so it is another viable coating option in the field of high-speed processing.
4. Chromium nitride coating (CrN)
One of the characteristics of CrN coating is its good anti-adhesion, which makes it the first choice for coating of machining tools that are prone to chip accumulation.
Unlike other coatings that have this or that color, CrN coatings are almost invisible, which is an excellent choice for customers who pursue the metallic feel of the tool itself. Such coatings can be applied silently, and the processing performance of high-speed steel cutting tools or carbide end mills and forming tools will be greatly improved.
5. Diamond coating (PCD)
PCD stands for Polycrystalline diamond and is the hardest coating currently available. Of course, its price is also the most expensive, and it usually provides the best performance for processing tools for non-ferrous metal materials.
Due to its high hardness, it is an ideal coating for machining graphite, metal matrix composites (MMC), high-silicon aluminum alloys and many other highly abrasive materials.
Combined with the use scenario and the original material of the end mill, the coating suitable for various tools is different. In addition, multi-layer coatings can be used in special cases; this coating also embeds other coatings between the surface layer and the tool substrate, which can further increase the service life of the CNC milling tool.
If you are choosing coated processing tools for your project, but you don’t know what the difference is between different coatings and what characteristics different coatings have. Hope the above content is helpful to you.
Cnc Carving Single Flute Carbide Diamond End Mill For Wood And Acrylic Spiral Endmill Tools