Evaluation of speed of melt evacuation in the technology of laser cutting of metals by the optical correlation method

A multichannel pyrometer was used to determine the speed of melt evacuation from an irradiated zone in laser-cutting technology with auxiliary gas. Local pulsations of brightness temperature were measured in four areas of ∼0.1 mm in diameter each spaced by 0.6 mm along the cutting front. A method is described for measuring the displacement rate of temperature heterogeneities during melt motion by mutual correlations of brightness-temperature pulsations calculated in neighboring areas. The necessity of preliminary frequency filtration of the measurement data may be due to propagation of a nonlinear wave in the melt on a metal surface under the impact of a gas jet.