A Study On The Processing Parameters Of Ion Beam Polishing

With development of science and technology, there is an increasing need of high degree of precision of aspheric optics in astronomy, military and scientific research, etc. And degrees of accuracy are higher than ever, which sometimes reach degree of sub-nanometer on RMS. Current figuring technologies at present are limited to higher degree because of the material removal mechanics they are based on. Ion beam polishing is a new efficient figuring technology that can get higher degree of precision of sub-nanometer. It is one kind of CCOS technology, which is based on ion sputtering. This article studies on characters of Kaufman ion source and removal function, ion beam polishing processing parameters. Main contents of this article including:1. Sigmund spluttering theory, structure and theory of Kaufman ion source. Sigmund spluttering theory is analyzed at first. Influences of some factors on spluttering yield are simulated with TRIM 2003 then followed, these factors including energy of ion, angle of ion incidence. KDIFS-500's ion source is one kind of Kaufman ion source, the structure of it is studied, and the theory of it is discussed. Further, thermal stabilization of KDIFS-500's ion source and relations of the parameters of it are experimented.2. Characters of ion beam removal function. With experiments, stabilization, linearity and reduplication of removal function are studied. First, variation of removal function during ion source warming-up process is observed. Second, stabilization of removal function is experimented and analyzed. At last, linearity and reduplication of removal function are proved.3. Influences of the processing parameters on removal function. This sector studied on influences of processing parameters on removal function. The processing parameters include the voltage and current of screen-grid, the voltage of accelerating-grid, the voltage of neutralizing cathode and the gas flow rate. Further more, the reason of the influences is analyzed based on the theory and structure of Kaufman ion source. At last, influences of the process parameters on removal function are summarized.4. Ion beam polishing experiment. Used a set of parameters of KDIFS-500, an ion beam function is experimented. And a piece of SiO₂ plane optics is polished used this removal function. Ability and efficiency of KDIFS-500 are proved.