Assessment of self-lubricating coated cutting tools fabricated by laser additive manufacturing technology for friction-reduction

Dry cutting acting as a green machining technology is a promising manufacturing process in industrial appli-cations; however, severe friction under dry cutting conditions aggravates tool wear and reduces tool life. Self-lubricating cutting tools exhibit excellent benefits in improving cutting properties and that can be used in sus-tainable machining. The complex process, low efficiency and thin coating thickness limit the production and use of present self-lubricating cutting tools with traditional methods. To enhance the lubricating effect and motivate the development of fabrication methods for self-lubricating cutting tools, Ni-based powders dispersed with MoS2 and Al2O3 particles were preset on the tool substrate; afterward, the self-lubricating coatings were deposited by laser powder-bed fusion additive manufacturing (AM) with a nanosecond fiber laser for cutting application. The self-lubricating coatings were characterized, and the friction and cutting performances of the AM self-lubricating coated tools (SLCs) were evaluated by sliding friction and dry machining tests. The results show that the developed SLC tools reduced the friction coefficient by 8.8-11.7%, cutting forces by 17.6-29.6%, and cutting power by 17.3-22.0% compared to conventional high-speed steel cutting tools (HSS). Built-up edge formation and tool wear were also significantly reduced. The observed mechanisms were attributed to the release of MoS2 particles from the coatings forming a lubricating film at the tool-chip interface, while the Al2O3 particles enhanced surface hardness. The results revealed the practicability of self-lubricating coated cutting tools fabri-cated by laser-based AM for friction-reduction, and that provide a cleaner process for dry cutting applications.