Everyone knows that coatings provide longer tool life and greater productivity. But do you know which coating is the best choice for your application? Here’s the basics on the most popular type of coatings being used today: TiN (titanium nitride), TiCN (titanium carbon nitride), ZrN (Zirconium Nitride), and TiAlN (titanium aluminum nitride) or AlTiN (aluminum titanium nitride) and advice on which one is right for your job.
TiCN is often the coating of choice for high-speed steel end mills, but in carbide you can run it at least 80 percent faster speed against uncoated solid carbide end mills. The only negative with TiCN is that it can fail under extreme heat; For this reason, it’s used in slower feed and speed applications.
TiAlN- or AlTiN-coated end mills
TiAlN- or AlTiN-coating are very effective at dissipating heat. In fact, they are so effective with dissipating heat into the chips that dry machining can often be utilized. The exception to this is when slotting where the chips need to be expelled out of the channel. The aluminum in the coating forms a gaseous aluminum oxide layer at the cutting edge where temperatures can reach more than 1800xF. This helps protect the carbide substrate from the damaging effects of heat and makes this coating ideal for high-speed and hard milling, especially in dry cutting.
Of course, there are other factors that should be considered when deciding on a coating for your tool and application. For example, the Zm coating has been specifically developed for milling aluminum.
Here at Midwest Cutting Tools, we have over 25 years of experience with coating tools.
Here’s our list of materials and preferred coatings.
General types of Steel : Nano Tek, AlTin, Tialn
Stainless & Tool Steel: Nano Tek, AlTin
Cast Iron: Nano Tek, AlTin
Because of its high strength and light weight, titanium is a favorite of the automotive, medical and micro-component industries. The same qualities that make titanium appealing for many applications, also make it one of the most difficult materials to machine.
Titanium is a poor conductor so heat generated during cutting doesn’t dissipate through the part or machine structure but instead concentrates in the cutting area. The high temperatures can lead to cutting edge chipping and deformation.
Our recommendation for cutting titanium: use a 4 or 5 flute variable flute pattern 38 degree helix tool with a Nanotek coating. This type of tool will resist chipping and reduce chatter while the coating’s protection actually increases as the heat increases.