Study On The Influence Of Polishing Particle Quality On K9 Glass Surface Roughness

As the normal and classical optical material in the modern optical manufacturing engineer, K9 optical glasses are widely used in the civil and national defence field. With the improvement of optical system preicision, the surface roughness of optical workpieces is much lower than before. As the necessary element in the process of chemical mechanical polishing, polishing slurry plays an important role, and its performance is the important factor of surface quality. This paper starts the theoretic and experimental study of polishing slurry dispersion based on the traditional polishing method. And the research results have been used in the polishing of flat K9 mirror with small size successfully, we got the surface roughness under 0.3nm finally. 1)The model of K9 workpiece polishing process with single polishing abrasive has been established, and the process has been simulated by ANSYS/LS-DYNA according to the Smooth Particle Hydrodynamics(SPH) method. The corresponding experiments have been made and the experimental results verified simulation results well. The relationship between K9 workpiece surface and abrasive particle size has been got by the experimental results and simulation results. 2)The element surface roughness in the polishing model has been calculated with the theory of surface roughness and statistics according to the simulation results of polishing process. The relationship model between element surface roughness and particle size has been made. And the relationship model between entire surface roughness and particle size has been made according to the relation of element and ring and surface.3)The image handling method has been proposed to study the dispersion of different polishing slurry. According to the electrostatic stabilization mechanism, polishing slurry dispersion was adjusted by adding dispersant Hexametaphosphate, and polishing slurry diapersion has best performance at 3%wt. Under this situation, polishing slurry dispersion at acidic and alkaline is better than neutral apparently. According to the steric stabilization mechanism, polishing slurry dispersion was adjusted by adding dispersant Acacia, and polishing slurry diapersion has best performance at 1%wt. Under this situation, polishing slurry dispersion has no large difference at different pH, polishing slurry dispersion at acidic and alkaline is a little better than neutral. 4)According to the polishing experimental study, the relationship between surface roughness and polishing slurry dispersion depends on the pH of polishing slurry. When the polishing slurry is asidic or alkaline, surface roughness has nothing with polishing slurry dispersion. When the polishing slurry is neutral, surface roughness is better as the polishing slurry dispersion is good.