Abstract
The study of the single-particle erosion mechanism is essential to understand the material removal mechanism in the non-contact polishing process and ultimately ensure the high-efficiency, non-damage, and ultra-smooth processing of optical glass. In this study, the theoretical model of smoothed particle hydrodynamics (SPH) is established to reveal the dynamic removal process of a single particle impacting the optical glass. The single-particle erosion mechanisms, which include ductile–brittle transition, crack initiation, and propagation, are discussed in detail through theoretical simulation. A series of particle impact experiments are designed to validate the correctness of the SPH model. The experimental data show good agreement with the simulation results in terms of the depth and width of the eroded craters. Thereafter, the SPH simulation is conducted by studying the effect of various impact parameters, such as impact speed, impact angle, and abrasive diameter, on the material removal process. With the gradual increase of impact velocity and particle size, the material removal mode changes from plastic removal to brittle removal. Although the large impact velocity and particle size increase the material removal rate, they lead to the occurrence of brittle removal and reduce the surface and sub-surface quality. When the impact angle is between 45° and 75°, the material removal rate is the largest, and the increase of the material removal rate does not cause damage to the subsurface layer of the material.
Highlights
Optical glass has become extensively used in aerospace, defense energy, and microelectronics due to its excellent material properties, such as high-temperature resistance, corrosion resistance, high strength, and good wear resistance [1,2]
Ultra-precision polishing technology such as fluid jet polishing, abrasive air jet polishing, and disc hydrodynamic polishing can be successfully used to suppress the occurrence of brittle fractures of optical glasses and obtain an ultra-smooth surface [6,7,8]
Studying the single-particle erosion mechanism is necessary to improve our understanding of the material removal and damage control mechanism in the non-contact polishing process, as well as achieve the high-efficiency, damage-free, and ultra-smooth processing of optical glasses
Summary
Optical glass has become extensively used in aerospace, defense energy, and microelectronics due to its excellent material properties, such as high-temperature resistance, corrosion resistance, high strength, and good wear resistance [1,2]. To effectively simulate the erosion removal process of brittle materials, smooth particle hydrodynamics (SPH), a meshless method, was proposed [26,27] This method is suitable for solving high-speed collisions and dynamic large deformation problems [28]. Hao et al [31] analyzed the mechanism of crack initiation and propagation during the impact process of angular particles on float glass by establishing a coupled FEM/SPH model, and found that incident orientation plays a key role in the erosion process. This study develops the SPH model for single-particle erosion of optical glass, and conducts a theoretical study of various impact parameters, such as impact speed, impact angle, and abrasive diameter, on the material removal process. A series of particle impact experiments are designed to validate the correctness of the SPH model by comparing the depth and width of the eroded craters between the simulation results and the experimental data
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