Ultrahard nanotwinned diamond (nt-D) is an excellent diamond material with higher hardness, better fracture toughness and thermal stability than the commonly used single crystal diamond (SCD), thus it is considered as a promising tool material applied in ultra-precision cutting. However, extremely high hardness results in the fabrication of nt-D tool more difficult than SCD because of very low machining efficiency when using the conventional mechanical methods. Aiming to mass-produce of nt-D tool, the femtosecond pulsed laser milling technique was applied, and the related phase transition mechanism was explored during processing nt-D. Then, a trochoidal trajectory was proposed to acquire high forming accuracy and sharp edge in this study. It is found that the cubic diamond within nt-D was transformed into amorphization directly rather than graphitization under laser processing, which is attributed to the enhanced phase stability for nt-D. Furthermore, the nt-D surface integrity processed by laser was mainly restricted by diamond falling-off pits dewetting from grain boundary. Then, an optimized trochoidal trajectory method was proved to effectively decrease the depth of the falling-off pits and improve the surface integrity by the aid of laser pulse delay. Through the distribution calculation of pulse overlapping with the deduced theoretical equations and processing parameters optimization of galvanometer rotation, an nt-D cutting tool was successfully fabricated with smooth surface and sharp cutting edge. Finally, the wear mechanism, wear resistance and cutting performance of the as-fabricated nt-D tool were explored through cutting testing of hard polycrystalline MgF₂. The results supported that nt-D tool exhibits better wear resistance and cutting performance than nanograined polycrystalline diamond (NPD) tool.

超硬纳米孪晶金刚石（nt-D）是一种优异的金刚石材料，比常用的单晶金刚石（SCD）具有更高的硬度，更好的断裂韧性和更高的热稳定性，因此被认为是超精密切削中一种有前途的工具材料。但是，由于使用传统的机械方法时加工效率非常低，因此极高的硬度导致nt-D工具的制造比SCD更加困难。针对nt-D刀具的批量生产，应用飞秒脉冲激光铣削技术，并在加工nt-D的过程中探索了相关的相变机理。然后，提出了摆线轨迹，以获得较高的成形精度和锐利的边缘。发现在激光加工下，nt-D内的立方金刚石直接转化为非晶化，而不是石墨化，这归因于nt-D的相稳定性增强。此外，激光加工的nt-D表面完整性主要受到金刚石晶界凹坑从晶界退潮的限制。然后，证明了一种优化的摆线轨迹方法，可借助激光脉冲延迟有效地减小掉落坑的深度并改善表面完整性。通过推导的脉冲重叠分布计算和推导的理论方程以及振镜旋转的加工参数优化，成功地制造了具有光滑表面和锋利切削刃的nt-D切削刀具。最后是磨损机理₂。结果支持nt-D刀具比纳米晶多晶金刚石（NPD）刀具具有更好的耐磨性和切削性能。