Sustainable improvement in dry turning using micro-grooved tools filled with carbon nanotubes: performance evaluation and environmental impacts

Dry machining is a sustainable alternative to reduce the environmental and health hazards associated with cutting fluids. Textured cutting tools filled with high thermal conductivity materials have emerged as a potential solution to improve heat dissipation and support the effectiveness of dry cutting. In this study, textured cutting tools filled with carbon nanotubes (CNTs) were developed and evaluated during the dry turning of AISI 1045 steel. Micro-grooves were designed based on thermal simulations to optimize heat dissipation from the cutting interface, with variations in width and depth. The tools were textured using laser machining and filled with CNTs through isostatic pressing. Machining tests were conducted under thirteen conditions, including conventional and textured tools under dry and wet cutting, and CNT-filled textured tools under dry conditions. The main parameters evaluated were tool life, cutting temperature, friction coefficient, forces, and water consumption. Results showed that CNT-filled textured tools significantly outperformed conventional and unfilled textured tools. In the best CNT-filled condition, tool life increased by up to 77 % compared to the dry conventional tool and also exceeded the performance obtained with cutting fluid. Friction and temperature reductions reached 21 % and 30 %, respectively. SEM and EDS analyses confirmed the presence of CNTs throughout the tool life and indicated reduced material adhesion and wear. The enhanced thermal conductivity and tribological properties of CNTs contributed to lower cutting forces and extended tool life, even without cutting fluids. These findings highlight the potential of CNT-filled textured tools to replace cutting fluids and promote more sustainable machining without compromising performance.