充气平衡法减小超轻反射镜加工中的网格效应（特邀）

对于传统蜂窝夹芯结构的反射镜，因加工过程中网格效应的存在，反射镜的面板厚度和蜂窝尺寸之间彼此关联制约着，严重影响反射镜的轻量化设计。针对蜂窝夹芯结构的超轻ULE反射镜，提出了一种充气平衡式减小网格效应的加工方法，运用控制变量法，通过实验比对了正常加工和充气平衡式两种研抛状态下网格效应的变化。实验结果表明:当反射镜面形精度RMS达到1/10λ （λ=632.8 nm）以上时，正常加工的面形图存在明显的网格效应，而充气加工则没有，可见反射镜内部充气可有效平衡加工压力，使反射镜在加工过程中有筋区域和无筋区域的变形趋于一致，从而有效减小网格效应。

Reduction of grid effect in ultra-light mirror machining by inflatable balanced method (invited)

For the mirror with traditional honeycomb sandwich structure, due to the existence of grid effect in the processing, the thickness of the mirror panel and the honeycomb size are correlated with each other, which seriously affects the lightweight design of the mirror. Aiming at the ultra-light mirror with honeycomb sandwich structure, an inflatable balanced processing method to reduce the grid effect was proposed. By using the control variable method to design test, the changes of grid effect under normal processing and inflatable balanced processing were compared. The experimental results show that when the mirror surface precision RMS reached more than 1/10λ （λ=632.8 nm）, there is an obvious grid effect in the normal processing without inflation, but not in the inflatable balanced processing. It could be seen that inflating the inside of the mirror could effectively balance the processing pressure and make the deformation of the reinforced area and the non-reinforced area tend to be the same during processing, so as to effectively reduce the grid effect.