Micro-nanoscale Removal Mechanism Of Materials Under Two-dimensional Ultrasonic Assisted Polishing

With the rapid development of science and technology,the demand and role of smooth or ultra-smooth surface components in various fields of society are increasing.In the standards of the optical field,the surface roughness Ra of optical components used for reflection and refraction must be Less than 0.012 microns,and in some high-precision cutting-edge areas,the requirements are more demanding.In order to meet the demanding requirements of related industries and obtain components with superior surface quality,many institutions and scholars have conducted a lot of research and experiments.Two-dimensional ultrasonic-assisted polishing is a new application in ultrasonic-assisted polishing.It has advantages that traditional polishing and one-dimensional ultrasonic-assisted polishing do not have.For example,material removal efficiency and surface quality are significantly higher than ordinary polishing and one-dimensional polishing under the same process parameters.Ultrasonic polishing.This article selects single-crystal silicon as the research object,studies its material removal process under two-dimensional ultrasonic-assisted polishing,and establishes its mathematical model,uses computer software to simulate the working process of abrasive particles at the micro-nano scale,and sets up an experimental bench.Orthogonal experiments and single-factor experiments of ultrasonic-assisted polishing were performed.The specific research content of the thesis includes the following aspects:(1)Combining the Hertzian contact theory,tribology theory,and the influence of ultrasonic vibration to propose a theoretical model of material removal under two-dimensional ultrasonic polishing,analyze the reasons for the effect of two-dimensional ultrasonic vibration field on material removal efficiency and surface quality during polishing,and propose Material removal rate equation.Matlab software was used to simulate the movement trajectory of polishing abrasive particles under the action of two-dimensional ultrasonic field.The effects of two-dimensional ultrasonic vibration on the polishing process were explained based on theoretical models and simulation results.(2)Use matlab software to carry out computer simulation on the movement trajectory of polishing abrasive particles under different ultrasonic vibration dimensions,and analyze the movement state,force situation and working condition of abrasive particles during work.And use Abaqus software to perform dynamic simulation of the impact process of free abrasive particles and the impact-scratch process of fixed abrasive particles in different dimensions,and compare and analyze changes in stress,material plastic strain and other changes in the working process of abrasive particles,and then determine different vibration dimensions The relationship between the material removal method of the workpiece surface.(3)Based on the kinetic theory,a model of abrasive grain impact-scratch single crystal silicon at the nanoscale was established,and the changing behavior of abrasive grains on the surface material of the workpiece under different polishing process parameters was compared and analyzed.Comparative analysis of stress,pressure and other indicators.(4)According to the main influence parameters in the theoretical model,a single-factor experiment and a four-level and five-factor orthogonal experiment scheme are designed,and an ultrasonic vibration-assisted polishing experimental bench is set up to perform an ultrasonic-assisted polishing experiment on a single crystal silicon workpiece.The gray correlation analysis was performed on the experimental results,and the degree of influence of experimental parameters on the results was discussed.