Tribological analysis and performance of a DLC coating on tungsten carbide micro-tools to use at tantalum precision machining

Owing to the increasing demand in ultra-precision machining of biocompatible materials, the demand to improve the performance of cutting processes and tools becomes progressively important. To increase the performance of the micro-tools leading to longer tool life and better surface finish, applications of solid lubricant coatings are necessary. Diamond-like carbon (DLC) coatings have been successfully used in many conventional cutting tools. In this study, the performance of the DLC coating in tungsten carbide micro-mills will be evaluated during the ultra-precision machining of a biocompatible material, namely, tantalum (99%). Experiments were carried out on the sliding pin-on-disk test and micro-machining both coated and uncoated. As expected, the DLC film deposited reduces both the friction coefficient and the wear. The results of the tests showed that the coated tools have less wear, evidenced by the distance 130% greater than the uncoated tools. Consequently, it also induces a reduction in the specific cutting forces (kS) and critical chip thickness. Thus, a better accuracy and surface finish on tantalum biocompatible parts can be reached.