Water assisted pulsed laser machining of micro-structured surface on CVD diamond coating tools

In this paper, a water assisted pulsed laser machining with mist spray was investigated for machining the microstructures on chemical vapor deposition (CVD) diamond coating tools. Firstly, the effect of water assisted condition on the machining quality and the transformation of Gauusian laser beam was analyzed. The theoretical calculation method of the shifted value of laser beam spot radius and defocusing quantity in the water assisted laser machining was presented. And then the effects of laser machining parameters included the laser power, the scanning speed, the scanning times and the scanning pitch were discussed in view of the ablation width, ablation depth, material removal rate and machined surface topography. Finally, three kind of micro-structures included micro groove array and cross-scale composite micro-structures were machined successfully on the CVD diamond coating tools by the developed water assisted pulsed laser machining method.