Emulating wear mechanism of DLC coatings in drilling of CFRP-Ti stacks by using cross-cylinder tribotest

The tribological interaction of cutting tool while drilling of carbon fiber reinforced plastic and titanium stacks (CFRP-Ti stacks) involves complex and rapid variation in wear mechanism due to disparate material characteristics. The abrasive CFRP and adherent titanium pose distinct thrust forces and torque along with complex wear mechanism, resulting in rapid tool wear. To improve tool durability and performance, Diamond-like Carbon (DLC) coatings are applied. However, traditional tribotest are incapable to mimic continuous contact renewal against multi-material stacks drilling. Here, for first time cross-cylinder tribotest against multi-material workpiece cylinder of [CFRP-Ti] n stacks is employed to imitate wear mechanism of DLC coatings for drilling/machining of CFRP-Ti stacks. The tribological analysis of different DLC coatings was performed against CFRP-Ti stacks and its individual constituents. The results showed cyclic variation in coefficient of friction (COF) against CFRP-Ti workpiece with aggressive wear action and complex tribological response, relatively unique and comparable to real drilling process. In comparison, the DLC-Bn coating showed best wear resistance with ~1.5–2.5 times durability when tested against Ti6Al4V and CFRP workpiece. Additionally, the results demonstrate the effectiveness of DLC-Bn coatings in mitigating variation to the sub-surface morphology of WC-Co substrate against CFRP-Ti workpiece. • Improvised tribotest development to mimic contact situation in drilling of CFRP-Ti stacks. • Exploitation of cross-cylinder tribotest to simulate tool wear of DLC coatings against multi-material stacks of CFRP-Ti workpiece. • Wear and COF analysis of different DLC coatings against Ti6Al4V, CFRP and CFRP-Ti stacks in cross-cylinder test. • Rapid wear of DLCs coatings occurs against CFRP-Ti stacks, compared to individual workpiece cylinders.