RESEARCH OF MATHEMATICAL MODELS OF THE FUSION PROCESS OF OPTICAL ELEMENTS OF DEVICES DURING SURFACE ELECTRON BEAM TREATMENT

Abstract

When processing optical elements with moving band electron flows (BEF), it is of great practical importance to predict optimal values ​​of the liquid bath depth that do not lead to changes in their shape and dimensions. In this regard, the formulation and solution of the problem of mathematical modeling of the melting process of optical materials processed by a moving BEF are relevant. Mathematical models of melting optical elements of devices made of optical glass of grades K8, K108, etc. of various geometric shapes (optical plates, rectangular bars, etc.) and sizes have been developed, taking into account the temperature dependences of the thermo-physical properties of the optical material (volumetric heat capacity, thermal conductivity coefficient), by a moving BEF during multi-cycle and single-cycle processing depending on the set of its parameters (electron flux current, accelerating voltage, distance from the processed surface, electron flux movement speed, and processing time). This allows us to more accurately calculate the temperature distributions along the surface and along the depth of the melt and the maximum thickness of the melted layer of the processed element for different values ​​of the controlled BEF parameters and to determine the permissible ranges of their changes, exceeding which leads to a violation of the flatness of the processed surface of optical elements, a violation of their geometric shape, a deterioration in the metrological characteristics of optical devices and, ultimately, to the failure of devices based on them.