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39Complex Systems of Charged Particles and their Interactions with Electromagnetic Radiation 2019
MODEL OF HIGH-SPEED SMOOTH LASER CUTTING TRANSPARENT MATERIALS
V.N. Tokarev
Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia,
e-mail: vtokarev56@mail. ru
A theoretical analytical model of controlled separation of optically transparent orsemitransparent materials using a moving focused pulse-periodic beam of femto-, or picosecond laseris proposed. The situation is considered, when at first in the thickness of the material by one or another wayone or more arrays of thin extended weakly ionized plasma filaments of micron or submicron diameter are created by irradiation (Fig.l), and after irradiation a separation of the irradiated material, applying an external tensile mechanical stress along the surface of the arrangement in the material of these arrays, is performed.
An important advantage of the proposed model is the possibility of finding optimal results such as high energy efficiency of the process and a highly record separation rate (in several m/s), and/or high smoothness of the side walls of the cut, and/or separation by an extremely low average power of the laser beam (in tens of mW) through the use of one or another choice of irradiation and material parameters, found on the basis of the model.In particular,it is shownthat for obtaining such an interesting for applications result as a smooth separation in addition to a proper choice of radiation parameters it is important also to fulfill a number of conditions (criteria) for the thermophysical, strength and elastic parameters of the material itself. Thus a class of materialsis found, for which a smooth separation is possible by the given laser method.
Fig. 1. Schematic of arrays of filaments created inside transparent material by a focused beam of pulse-periodic laser, ii is velocity of relative motion of the beam and the sample.
Based on the model, a method is proposed for controlled separation of a wide variety of transparent materials - amorphous, crystalline or ceramic, superhard and heavy-duty, such as sapphire, chemically tempered and non-tempered glass, display glass, diamond, sitall, as well as multilayered and flexible materials. Specific irradiation parameters for the separation of materials of different thicknesses from 50 |im to about 10 mm are found quantitatively. Comparison of the calculated parameters with experimental data on high-speed smooth separation and filaments plasma temperature shows the adequacy of the model.
