Research studies on kerf quality of cutting single crystal diamond with water-jet guided laser

Water-jet guided lasers are an advanced technology which offers precision and efficiency for processing single crystal diamonds (SCD). In this paper, the slicing of high-pressure-high-temperature (HPHT) SCD samples via water-jet guided laser and conventional dry-laser were performed respectively. It is analyzed by SEM and Raman methods that a “V-shape” has turned out in a cross section and a graphite layer on kerf surface by conventional dry-laser slicing, but a smoothly flat cross-section without diamond structure change on kerf surface was achieved by water-jet guided laser slicing. The relationship between laser parameters and cutting depth were tested, in which cutting depth is linear growth with increasing laser power and cutting depth was decreased in general with increasing cutting speed but low cutting speed which causes bad kerf quality. The optimal quality of kerf surface was obtained when the cutting speed and laser power are set as 8mm/s and 11 W, respectively, and the corresponding minimum heat-affect zone (HAZ) is 3.983 μm. After laser power increased to 11.8 W, the SCD sample could be sliced completely with 8.306 μm of HAZ.