Cutting performance of DLC coated tools in dry machining aluminum alloys

The purpose of this study is to examine the impact of tribological properties of DLC coatings on cutting performance. In this work, DLC was prepared on a cemented carbide substrate by using a vacuum arc discharge with a graphite cathode. DLC was identified as a nonhydrogenated amorphous carbon film with the thickness of 0.1 mum. DLC coatings were evaluated in a pin-on-disk test as well as in aluminum alloy machining. DLC had a low friction coefficient (0.1) against aluminum alloy and an excellent anti-adhering property. The results showed that DLC coated tools can be used to reduce adhesion between a tool and a work material, and the formation of a built-up edge. In order to analyze the cutting process, a finite element method (FEM) simulation at the tool-chip interface was employed, to compare the experimental evidence. In particular, the comparison was carried out taking into account the chip shapes and cutting force. The FEM simulation of a chip formation process was in qualitative agreement with the experiments, and this enabled an explanation of the phenomenon of the cutting process. In the case of dry machining of the aluminum alloys, DLC coatings enhance the tool performance, the machined surface integrity and the tool life compared to an uncoated tool. (C) 2004 Elsevier B.V. All rights reserved.