Variable-step-pitch micro-milling repair tool path generation method for optical crystal surface damage points

Abstract

The invention discloses a variable-step-pitch micro-milling repair tool path generation method for optical crystal surface damage points, and belongs to the technical field of optical material and optical element surface repair. The method aims to delay the modulation effect of a constant-period tool mark generated by a soft and brittle KDP crystal in micro-milling repair on incident laser, and achieve the purposes of improving the laser damage resistance of a KDP crystal element and prolonging the service life of the KDP crystal element. The method is characterized by: establishing a mathematical model of a repaired contour; determining discrete contact points of the cutter and the contour for controlling the motion trend of the pseudo-random trajectory when the cutter mills and repairs the contour by using a GPR trajectory generation method; utilizing the established repair contour mathematical model and the selected micro-milling cutter size; interpolating the cutter location control point set into a space curve by applying an NURBS modeling method; and establishing a curve in UG software according to the curve model, and performing machining process simulation by taking the curve as a repair track. It is verified that the method has a good elimination effect on the constant-period knife lines, and the strong laser damage resistance of the method is improved.

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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