The tool surface coating reduces the friction between the tool and the workpiece surface, reduce the cutting force, reduce dependence on the cutting fluid lubricating.
At present, the coating technology for high-speed dry cutting tools are mainly two types, one is the "hard" coating, such as tin, tic, al2o3 like. Such coated tool surface hardness, wear resistance, which, after the anti-tic coated tool flank wear are strong; tin-coated tools you have better resistance to crater wear ability. The other is the "soft" coating, such as coating mos2, ws2 coatings. Advantage of such coated tools are surface friction coefficient is very low (about 0.01), can reduce the friction between tool and workpiece, between the tool and chip cutting, also called self-lubricating tools. For example, the Swiss Agency for Development of "movic" soft coating technology applied in the tool surface layer mos2. Cutting experiments show that while dry-si tapping on aluminum content of 9% by the workpiece, machining only ordinary tap holes 20, tialn coating tap hole 1000 can be processed, and the coating movic taps can be processed 4000 holes. tialn is commonly used in high-speed dry cutting coating material, it mos2 based "movic" soft coating when used in combination, for better processing results.
