Effect of scanning pitch on nanosecond laser micro-drilling of silicon nitride ceramic

Effect of laser scanning pitch on micro-holes drilling of silicon nitride (Si3N4) ceramics was investigated in this study. Results showed that laser scanning pitch had a significant influence on the geometry of holes. For instance, the taper angles of holes increased with the increase in scanning pitch. Measurement data also showed that the diameters and circularity decreased with the increase in scanning pitch at the both entrance and exit sides. It was also noted that the change of scanning pitch had little effect on the dimensions of holes at the entrance side. The elemental composition was closely related to the distance from the edge of the hole due to the chemical reaction of laser machining in air. The surface toughness increased with the increase in scanning pitch. The present study suggested that the higher processing quality of holes could be achieved at the smaller scanning pitch.