Interaction of Laser Radiation (UV) with Materials.

The interaction of laser radiation with matter is considered. Marking of non-metallic materials re- quires heating below the softening point, heat treatment requires heating to temperatures above the phase transformation temperature, laser cutting of metals occurs with heating above the melting point, and engraving occurs above the melting or evaporation point. The choice of a laser for a certain type of processing is determined by the specific impact of laser radiation on a given material and the characteristics of the technological task at hand. Laser radiation in the UV range with a wavelength of λ = 355 nm, which can be obtained through third harmonic generation, is increasingly used in industry. Recommendations are pro- vided for the use of low-power pulsed UV lasers for marking, engraving, cutting of metallic and non- metallic materials and surface hardening of steels. The paper presents the results of a study of the effect of laser radiation wavelength on metal engraving. The studies show that engraving with a beam with a radiation wavelength of λ = 0.355 µm allows obtaining a high-quality image without melting the surface. Due to the fact that radiation with a wavelength of λ = 0.35 µm is equally well absorbed by metals and dielectrics, UV-lasers can be used for separation operations in microelectronics, for example, for cutting flexible printed circuit boards with high quality. Reducing the diameter of the focus spot of the UV-laser compared to the focus of the CO₂-laser makes it possible to reduce the radiation power and perform better cutting. Comparison of thermal strengthening of steels by volume hardening, laser hardening with melting, laser hardening by UV-radiation showed high efficiency of hardening by UV-radiation. Laser processing in the UV-range is rationally used for local surface hardening of fuel equipment parts, cutting tools [ABSTRACT FROM AUTHOR]