Effect of micro-textured morphology with different wettabilities on tool cutting performance

Difficult-to-machine materials such as Ni-based superalloy suffer from severe tool wear and poor surface quality; therefore, the cooling mechanism is the key to improving machining performance and reducing the environmental pollution in manufacturing. In the past, plenty of studies verified that the micro-texture on the cutting insert improved the cutting performance under the same cooling condition. The main explanation is that the second generated cracks caused the capillary siphon phenomenon and increased the wettability of the subsurface of the workpiece. In order to investigate the effect of surface wettability differences on the cutting performance of the tool under different micro-textured morphologies, three types of micro-textured CBN tools with pit, linear, and sinusoidal morphologies were fabricated by laser machining technology. Through cutting experiments on Inconel 718 Ni-based superalloy, the cutting force, tool wear, and machined surface roughness of different micro-textured tools were compared and analyzed. The relationship between cutting performance and wettability of different shaped micro-texture was obtained by measuring the contact angle using PT-705B optical angular contact meter. The experimental results show that the presence of surface micro-textures enhances the surface wettability of the tool. It effectively reduces the cutting force and slows down the rake face's wear and the machined part's surface roughness. Compared with other morphologies, sinusoidal micro-textured tools show the best cutting performance. Among the four morphologies of micro-textured tools, cutting performance improvement increases with surface wettability. More generally, these primary findings are consistent with research showing that wettability is critical in micro-texture generation for high-performance machining. The conclusion is very much the key component in future attempts to overcome the assumption of the capillary siphon phenomenon on the subsurface of the workpiece.