Research On Processing Properties Of Optical Surfaces Based On Molecular Dynamics

Ultra-precision machining was first used in aerospace and defense technology and other fields.With the maturity of its technology and the growth of market demand,it has been widely used in the civilian industry,such as mobile phone lenses,aspherical glasses and optical instruments.With the development of science and technology and the improvement of people's living standards,the demand for products with high-speed signal transmission and high-quality optical surfaces is increasing.However,traditional ultra-precision machining materials,such as copper and aluminum,have limited performance due to their limitations.It is difficult to meet the demand for high performance,so new materials with more outstanding performance are needed,and the more typical ones are amorphous and single-crystal materials.Amorphous materials have no crystal structure,such as dislocations,grains,and grain boundaries.They are homogeneous and isotropic.They also have a combination of metals and glass.Under certain conditions,they have a"self-healing"characteristic.Single-crystal materials have no grain boundaries,have a highly ordered structure,and the atoms are arranged in the same direction.They have excellent electrical properties and signal transmission properties.Under the premise of meeting the above requirements,amorphous and single-crystals will become ideal materials in the ultra-precision field,but the lack of in-depth and unclear processing mechanisms limits their applications in ultra-precision optical products,so their performance research has become one of the most urgent tasks.Based on the above requirements,the properties of amorphous and single crystal materials are studied in this paper.Pd₄₀Ni₁₀Cu₃₀P₂₀ amorphous alloy and single-crystal copper are used as examples for cutting experiments.The results show that:(1)Pd-based amorphous alloys are very suitable for ultra-precision cutting,and the surface roughness of the workpiece after processing is about 3 nm;(2)irregularities appear along the path of the tool mark in the outer circle area of the workpiece micro/nano oxidized structure;(3)when the temperature of the Pd-based amorphous alloy processing area reaches a certain value,the surface of the workpiece shows a self-healing effect;(4)single-crystal copper with different crystal planes undergoes ultra-precision cutting different fan-shaped patterns will appear on the surface,of which(100)crystal plane will produce four quadruple symmetrical fan-shaped patterns,(110)crystal plane will produce four double-symmetrical fan-shaped patterns,and(111)crystal plane will produce three triple-symmetric fan-shaped patterns;(5)in the ultra-precision cutting of single-crystal copper,the cutting force will change periodically;(6)among the three single-crystal copper with different crystal planes,the(100)crystal plane is most suitable for ultra-precision cutting.The surface quality was the best,followed by the(111)crystal plane,and the(110)crystal plane had the worst surface quality.For amorphous,we found its oxidation mechanism.Based on the oxidation phenomenon of the workpiece surface,a cutting thermal model and molecular dynamics simulation were established in this paper.The oxidation mechanism and suppression method of the workpiece surface were studied through experimental results and theoretical analysis.This research provides important theoretical and technical support for the application of amorphous alloys in the manufacture of optical molds.For the single-crystal,we found its fan-shaped pattern.Based on the generation of the fan-shaped pattern on the workpiece surface,we collected and analyzed the force signal in this paper,and established a dynamic cutting system to predict the workpiece surface morphology and use molecular dynamics simulation study of the material deformation mechanism and surface formation mechanism during its ultra-precision machining,theoretically revealed the removal mechanism of single-crystal copper materials with different crystal plane orientations and the causes of surface morphology.The practical application in the manufacture of parts provides a useful reference.