A Comparative Study of Nanosecond Laser Processing of Silicon Nitride Under Two Conditions
X. Li, K. Shao, D-D. Chang and X-H. Chen
The influence of machining environment on the processing quality of silicon nitride ceramics during nanosecond laser machining was investigated. Under controlled laser parameters, the process performance of two environments-ambient air and water-jet assistance-was systematically compared. Experimental results demonstrate that nanosecond laser processing in air produced grooves with a depth of 110.36 μm and a width of 10.27 μm on the silicon nitride surface. Under water-assisted conditions, the grooves fabricated by nanosecond laser processing exhibited a depth of 80.13 μm and a width of 5.76 μm. Moreover, it effectively eliminates surface recast layers and microcracks. In water-jet-assisted nanosecond laser processing of silicon nitride, the effective cooling provided by the water jet significantly reduces heat accumulation in the machining zone. The impact of the water jet promotes the rapid expulsion of molten material from the groove and facilitates the timely removal of byproducts, thereby enhancing machining quality. This study provides critical process optimization insights for precision laser machining of hard and brittle materials, demonstrating that water-jet-assisted technology effectively suppresses thermally induced defects commonly associated with conventional laser processing.
Keywords: Nanosecond laser processing, water jet-assisted laser processing, silicon nitride, depth