The fabrication of polycrystalline diamond micro drill based on ultrashort pulsed laser

High precision polycrystalline diamond (PCD) micro cutting tools with complex geometrical features which widely used in the field of aerospace, automotive, electronics, etc. are difficult to fabricate by traditional processes. Ultrashort pulse laser (ULPL) with extremely high peak power and short pulse duration is the ideal tool for processing PCD materials. In this study, an industrial picosecond laser source with the wavelength of 1064 nm and the pulse duration less than 10 ps was used to fabricate PCD micro drills. A graphical user interface (GUI) and a computer-aided manufacturing (CAM) module have been developed. A twist PCD micro drill with a diameter of 0.75 mm was successfully fabricated by picosecond pulsed laser roughing and grinding finishing. The mechanisms of ablation removal and surface integrity generation in picosecond pulsed laser processing of PCD materials were discussed. The results show that PCD micro drills roughed by a picosecond pulsed laser have sharp geometric edges. The thickness of thermal damage layer induced by the picosecond pulsed laser is very small, which could be completely removed in the grinding finishing process. Compared to conventional grinding, the fabricate time of PCD micro drill based on the newly proposed method is reduced by 48.2%.