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Development of high-power laser ablation process for polycrystalline diamond polishing Part 2: upscaling of PCD ultra-short pulsed laser ablation to high power

Properties of diamond are extreme. Since the first successful synthesis of diamond in 1955, the use of synthetic diamond has widely spread into diverse industries (e.g. manufacturing, electronics and optics). However, being the hardest material known, the manufacture of diamond material into an engineered tool is extremely challenging. The polishing process remains a traditional mechanical method existing for over hundreds of years. The development of alternative ways of polishing diamond is an active subject of research and has recently been investigated in topics such as chemically assisted mechanical polishing or ion beam polishing. Laser polishing is another alternative and a state-of-theart laser polishing method is presented in this paper. A high-power femtosecond laser ablation process is developed to achieve a high throughput polishing process of polycrystalline diamond composite (PCD) wafers. Laser ablation trials are carried out with a femtosecond laser delivering over 80W average power on three different PCD grades synthesized by high-pressure/high-temperature. The role of the fluence is highlighted and the effect of the burst mode on PCD is demonstrated for the first time to the best of our knowledge. Eventually, the roughness of the initial surface on fine grain diamond material is reduced by two while the ablation rate is twice higher than the removal rate achieved by mechanical polishing.