Advance in design and fabrication strategies for medical micro-cutting tools

Medical micro-cutting tools, with ultra-precision machining ranging from 1 to 10 μm, enable the removal of micro-cancerous tissues during surgery. The geometrical design and dimension of the tool's cutting edge is a key factor that determines the tissue damage level and surface quality. Currently, the majority of commercial medical micro-cutting tools are scaled down from the conventional macro-cutting tools. This approach may result in crack expansion and extensive surface damage in soft tissues influenced by the size effect. This may lead to significant cutting forces and stress concentration. Therefore, it is necessary to conduct a thorough analysis for the improvement of the design and manufacturing methods of micro-cutting tools. This will allow the determination of cutting parameters for micro-tools to facilitate the removal of tiny cancerous tissues and reduce the surface roughness of normal tissues. Here, we present a comprehensive and up-to-date review of medical micro-cutting tools in terms of their structures and design, materials and compositions, fabrication techniques, material removal mechanisms, and machining performances. We also outline and discuss biomedical applications to offer theoretical guidance for selecting appropriate micro-cutting tools.