Cutting performance of different types of diamond-like carbon coatings

The cutting test of aluminum alloy using end mills coated with two types of DLC films (ta-C and a-C:H) was conducted under lubrication conditions of either dry or alcohol mist. The dry cutting test showed that there was little adhesion on the ta-C tool, but much adhesion on the a-C:H tool. It seems that the friction mechanism under dry cutting was different between ta-C and a-C:H. And the alcohol mist cutting test showed that there was little adhesion on neither ta-C nor a-C:H tool. Therefore, it is clear that the combination of DLC film and alcohol mist reduced adhering to the tool in cutting aluminum alloy. When the cutting distance was extended, DLC film almost disappeared from the a-C:H tool surface and adhesion occurred on the tool base material. In contrast to this, DLC film remained on the ta-C tool even after the long distance cutting. Therefore, the amount of adhesion must be influenced by the durability of DLC film coated on the cutting tool. The ta-C is superior as a coating film on the cutting tool for aluminum alloy.