Ultra-short pulsed laser processing of single crystalline diamonds for tooling applications

This study investigates the feasibility of using ultra-short pulsed (USP) lasers to fabricate single crystalline diamond (SCD) tools. SCD has exceptional mechanical, tribological, and thermal properties and offers excellent performance in the precision machining of hard and brittle materials over polycrystalline diamond and diamond-coated tools. However, the anisotropic nature of the SCD makes it difficult for laser machining because the material shows susceptibility to cracking, defect growth, and breakout depending on its crystallographic orientation. Anisotropy needs to be considered while optimizing the geometry of the tool to minimize wear and improve tool performance. An advanced four-axis laser machining approach with optimized laser parameters and temporal beam shaping is used to mitigate challenges related to defect growth and orientation dependence, leading to the production of high-quality single cutting-edge SCD tools. Cylindrical diamonds and diamond crystals with top surface planes {100} and {111} are used in the study. The occurrence of defects in the diamond when laser machined and their dependence on the crystallographic orientation along the circumference of the diamond is thoroughly investigated via SEM, electron backscatter diffraction, and light microscopy images. Finally, the laser-manufactured SCD tools are tested by turning fully sintered zirconia ceramics (3Y-TZP-A). USP laser machining of SCD is demonstrated to be a viable alternative to traditional manufacturing methods for producing high-quality SCD tools with unique properties and performance. The results further emphasize the importance of understanding the crystallographic orientation dependence when laser machining crystalline materials like diamonds.