On generating of recoil pressure by laser-induced thermocapillary melt removal

Effect of deep penetration is accompanied by capillary channel formation which ensures beam penetration deep into the metal. This effect is widely used in thermal laser technologies, including the additive manufacturing by the method of selective laser melting of metal powders for 3D printing of parts with complex geometry. The experimental data are analyzed to determine the possibility of creating a recoil pressure on metal targets (Fe, Al, Cu) by thermocapillary melt splash when exposed to laser radiation with parameters characteristic of deep penetration mode. Correlation between calculated and empirical data is obtained for recoil pressure and melt removal rate. The conclusion is made about a possibility to generate a recoil impulse by thermocapillary removal and splash of melt. The assumption about additional electrocapillary accelerating of molten metal in conact with laser plasma is substantiated.