Tech Tip: Coatings for Solid Carbide End Mills

For maximum performance and Metal Removal Rates (MMR), selecting the proper coating depends on on workpiece material and application.   

Titanium Nitride (TiN) coatings are used for general-purpose milling operations in softer materials. The coating offers high surface lubricity, reduces friction, and increases chip flow.  The resistance in heat and hardness allows the tool to run about 20-30% higher machining speeds than uncoated end mills. 

Titanium Carbonitride (TiCN) is harder than Titanium Nitride (TiN) at low cutting temperatures. It features good abrasion resistance and is very good in milling applications for steels, stainless steels, and non-ferrous materials. End mills coated with TiCN should be operated at speeds up to 50% higher than uncoated mills. If process temperatures get too high hardess drops significantly.

Titanium Aluminum Nitride (TiAlN) coatings are high-performance coatings used for all types of materials. It is about the same hardness as Titanium Carbonitride (TiCN,) but maintains hardness at much higher cutting temperatures. This makes TiAlN very effective in high-temperature alloys, high-speed machining, and dry milling applications. End mills coated with TiAlN have a high resistance to heat and oxidation and should be operated at speeds up to 100% higher than uncoated mills.

Aluminum Titanium Nitride (AlTiN) coatings are harder than Titanium Aluminum Nitride (TiAlN). It offers higher abrasive and heat resistance. It extends tool life and reduces cycles commonly used for machining aircraft and aerospace materials, nickel alloys, stainless steels, titanium alloys, cast iron, and carbon steels.

Aluminum Chromium Nitride (AlCrN) coatings are extremely resistant to high temperatures and wear. The coating features chromium instead of titanium which offers better performance over Titanium Aluminum Nitride (TiAlN). The coating can be used for machining stainless steel, titanium, cast iron, tool steels, and other difficult materials. It can be used in a variety of machining applications.

Kennametal is constantly evaluating and improving to yield higher productivity and consistency on tools and workpiece materials. Kennametal’s Research and Development department updates recommendations, marketing literature, and catalogs based on continuous improvements to our coating process. Refer to our basic speeds and feeds calculator to help guide you.

To achieve benefits from high-performance coatings, they must run at significantly higher speeds than other coatings. If coated tools run at parameters other than those recommended, they can be counterproductive. Follow the manufacturer’s recommended starting points and work from there.