A tool trajectory generation method for micro-milling repair with variable step distance for damage points on the surface of optical crystals

Abstract

The invention discloses a method for generating a tool track for variable-step-pitch micro-milling repair aimed at damage points on the surface of optical crystals, belonging to the technical field of optical materials and optical element surface repair. The invention aims to delay the modulation effect of the constant-period knife marks produced in the micro-milling repair of the soft and brittle KDP crystal on the incident laser, so as to improve the anti-laser damage ability of the KDP crystal element and prolong its service life. Technical points: establish a mathematical model of the repair contour; use the GPR trajectory generation method to determine the discrete contact points between the tool and the contour when the tool mills the repair contour to control the movement trend of the pseudo-random trajectory; use the established mathematical model of the repair contour and the selected micro Milling cutter size; use NURBS modeling method to interpolate the tool position control point set into a space curve; establish a curve in UG software according to the curve model, and use this curve as the repair track to simulate the machining process. It has been verified that the invention has a good effect on eliminating constant-period knife marks and helps to improve its ability to resist strong laser damage.

Description

technical field [0001] The invention belongs to the technical field of optical materials and optical element surface repair, and in particular relates to a variable step-pitch precision micro-milling repair process for laser damage points on the surface of a large-diameter KDP crystal element. Background technique [0002] In order to pursue reliable and controllable clean nuclear fusion energy, countries around the world have built large-scale laser-driven inertial confinement fusion facilities (ICF), such as the National Ignition Facility (NIF) in the United States and the Shenguang Laser Facility (SG) in China. In such a huge laser system, tens of thousands of large-aperture, high-precision, and high-quality optical components are required. Among them, the KDP functional crystal material should have unique optical properties and be used to make photoelectric switches and frequency doubling components, becoming an irreplaceable core device in the current laser-driven inert...

AI Technical Summary

Problems solved by technology

In the actual use of KDP crystal components, the strong laser in the ICF optical path system is extremely sensitive to the residual knife marks with a constant period. Due to the interference and diffraction effects of the laser, the light intensity will be enhanced inside the KDP and inside the downstream fused silica optical components. Hot spots, which in turn cause new damage to optics

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