Inert ambiance-assisted laser ablation of CVD diamond leads to enhanced surface quality and grindability

Abstract

Diamond is a versatile ultimate engineering material that has been recommended for numerous purposes, especially micro mills. Laser-assisted precision grinding is substantiated to be a promising approach for fabricating diamond micro tools. Yet, in practice, the short pulses that render express elimination will deteriorate the flatness of the tool surfaces, bringing about a boost in the risk of edge collapse and a shrink in yield during the subsequent precision grinding. The tactic of ambiance-assisted laser ablation, which introduces an auxiliary gas during the irradiation to promote the ablated domain quality, is proposed in this investigation. Specifically, a raster scanning-based transient temperature distribution simulation is erected to comprehend the ablation mechanism of the chemical vapor deposition (CVD) diamond. Additionally, it can be deduced that the inert nitrogen with high cohesive energy curbs the instantaneous deflagration of oxidation on the Knudsen layer and the activity of dangling bonds that are desorbed at high temperatures. The nitrogen-assisted laser ablation of the diamond sample leads to a maximum dwindling in surface roughness of 33% compared to that with non-ambiance-assisted. Subsequently, the laser-ablated surface optimized by an inert atmosphere is precisely ground with a fine abrasive grinding wheel. The detection of the sharp cutting edge ( r β = 1.74 μm) with almost no notch and the ground flank surface with the roughness of 168 nm indicates that accessing the inert auxiliary atmosphere during ablation can enhance the surface quality of the machined diamond and the corresponding grindability.