Dry Drilling Performance Enhancement using Optimized Diamond-Like Carbon Coatings

Abstract This study demonstrates the performance enhancement of drill bits during dry cutting operation of LM6 aluminum alloy and bright mild steel using optimized Diamond-Like-Carbon (DLC) coatings. DLC coatings are deposited using Plasma Enhanced Chemical Vapour Deposition (PECVD) process by varying the process parameters, bias voltage, bias frequency, gas mixture, and working pressure. DLC coatings were grown over the silicon, high-speed steel, and stainless-steel pin substrate. Coating’s chemical, composition, topography, and mechanical properties measurements were checked using Fourier Transform Infrared (FTIR), micro-Raman spectroscopy, Atomic Force Microscopy, and intrinsic stress & nano-hardness/micro-hardness tester, respectively. Coating deposition and optimization were carried out as per the Taguchi method. Further, the optimized DLC coatings tribological test and the effect of DLC coating on the tool life were performed. Results showed that the DLC-coated substrate had less wear loss and coefficient of friction than the uncoated substrate. The dry-cutting test showed that coated drill bits produce a better surface finish and consume less power in the drilling operation than uncoated drill bits. This is due to the low coefficient of friction and low wear loss of the DLC coatings.