Surface Treatment of TiN Coating on End Mills
End mills are some of the most common cutting tools used in the machining industry. With these tools, it is possible to cut and shape a variety of materials including wood, plastic, metal and many more. To increase the service life and performance of the end mills, they are often treated with a coating, such as titanium nitride (TiN). The TiN coating is applied via various processes, including physical vapor deposition and chemical vapor deposition. The purpose of this paper is to discuss the surface treatment of TiN used on end mills.
As previously mentioned, TiN is often used as a coating for end mills to increase their performance. This hard coating offers increased wear and corrosion resistance, as well as improved performance for heat-treated materials. The process by which TiN is applied can vary, but most often involves chemical vapor deposition. This technique involves the introduction of a reactive gas, such as ammonia and argon, into a vacuum chamber which then reacts with a metallic substrate and produces a thin film of TiN. This film is typically in the range of 0.1 to 1 micrometer thick.
Once the TiN has been applied, it must then be surface treated to ensure it is properly adhered to the end mill. This typically involves the use of mechanical means such as grinding and polishing. The grinding process removes any imperfections in the surface of the TiN, such as lumps or bumps, while the polishing process gives the end mill a smooth finish with improved reflectivity. After the grinding and polishing process, the surface of the end mill is then treated with a protective coating. This could include a thin layer of oil, wax, or silicone to prevent corrosion, oxidation, and wear.
In addition to the mechanical processing of the TiN, it can also be prepared with chemical surface treatment processes such as etching and passivation. Etching involves exposing the PCD to a mixture of acid and alkali to modify the surface of the end mill. This can result in a slightly rougher surface which can increase adhesion and corrosion resistance. The passivation process uses a chemical solution, such as citric acid, to form a thin oxide film on the surface. This provides additional protection against corrosion and wear, as well as improving the mechanical properties of the TiN.
Overall, the surface treatment of the TiN coating on end mills is a critical step in ensuring its performance and increasing its longevity. Mechanical and/or chemical processes can be used to improve the adhesion of the coating as well as its corrosion and wear resistance. This will result in improved performance of the end mill, which can help increase productivity and efficiency in the machining shop.
