A comparison of laser beam machining of micro-channels under dry and wet mediums

Micro-channels have been fabricated in nickel-based superalloy (Inconel 718) through laser beam machining (LBM). Two machining mediums are employed: dry and wet medium. Under the dry medium, laser beam passes through air prior to strike with target surface while under wet medium, the laser beam first travels through a layer of distilled water and reaches the substrate after. For both the machining environments, effects of laser power, pulse repetition rate, and laser scan speed on machined channels' width, depth, and taperness are investigated. A comparison of parametric effects on machined channels' profiles has been carried out for the said machining conditions. The results reveal that LBM under distilled water is more productive than LBM under air environment. In one step, wet machining conditions allow to generate a set of two micro-channels, and dry conditions generate one micro-channel. Further, to achieve the optimum dimensions of micro-channels, the appropriate level of each of the investigated laser parameter is proposed.