基于介电泳效应的高速抛光电极分布仿真研究与实验验证

目的解决传统平面环抛过程中存在的两种问题:(1)抛光液受抛光盘和工件旋转离心力作用而抛光液在加工区域分布不均,导致加工工件高平面度差;(2)抛光液受到的离心力作用限制了抛光盘转速,导致抛光效率低。方法提出一种基于介电泳效应的平面抛光方法(DEPP),在抛光区域增加一个非均匀电场,利用中性粒子在非均匀电场中极化后受介电泳力的作用,使其具有向电极和抛光区域中心运动的现象,降低旋转离心力对抛光液的甩出作用,实现对平面工件的高速、高精度抛光。采用有限元分析软件数值模拟极化后磨粒所受介电泳力对离心力的抑制作用,优化产生非均匀电场的不同电极宽度,得到最优非均匀电场电极分布参数,实际测量优化电极后抛光液所受介电泳力的大小和方向,最后搭建试验平台验证介电泳效应高速抛光平面工件的有效性。结果提高抛光盘转速,进行抛光磨砂玻璃对比实验,加工1 h以后,采用介电泳效应抛光能完全去除玻璃磨砂层,工件平整度好,最终RMS值为0.276λ;无介电泳效应抛光后,工件中心部分磨砂层仍有存在,工件平整度相对较差,最终RMS值为0.694λ。通过测量加工去除量,介电泳效应抛光比无介电泳效应抛光的去除率提升了18%结论通过仿真模拟和实验验证,证明了调整电极布置形式以及优化电极分布参数后,介电泳效应高速平面抛光的方法能够有效提升抛光效率和抛光后工件表面平面度。

Simulation and Experimental Verification of Electrode Distribution for High Speed Polishing by Dielectrophoresis Effect

The work aims to solve the problems existing in the traditional planar ring polishing process:1)the polishing fluid is distributed unevenly in the processing area due to the centrifugal force caused by rotating polishing lap and workpiece,resulting in high flatness of workpiece;2)the centrifugal force acting on the polishing fluid also limits the rotational speed of polishing lap and reduces polishing efficiency.A planar polishing method based on dielectrophoresis effect(DEPP)was proposed:a non-uniform electric field was added to the polishing area,and neutral particles were subject to dielectrophoretic force after being polarized in the non-uniform electric field,so that the neutral particles had the phenomenon of moving towards the center of the electrode and the polishing area,the throwing effect of rotating centrifugal force on polishing fluid was reduced,and high-speed and high-precision polishing of planar workpiece was realized.Finite element analysis software was used to simulate the suppression effect of centrifugal force by dielectrophoretic force on the polarized abrasive particles,optimize the different electrode widths of non-uniform electric field and obtain the optimal parameters of non-uniform electric field electrode distribution.The magnitude and direction of dielectrophoresis force applied to polishing fluid after optimization of electrodes were actually measured.Finally,a test platform was built to verify the effectiveness of dielectrophoresis effect on high-speed polishing planar workpiece.The comparative experiments of polishing ground glass by increasing the rotational speed of polishing lap were as follows:after one hour processing,the grinding layer of glass could be completely removed by dielectrophoresis effect polishing,the workpiece smoothness was good,and the final RMS value was 0.276λ.After polishing without dielectrophoresis effect,the grinding layer of the central part of the workpiece still existed,the workpiece smoothness was poor,and the final RMS value was 0.694λ.By measuring the removal amount,the removal rate of dielectrophoresis polishing was 18%higher than that of polishing without dielectrophoresis.Through simulation and experimental verification,it is proved that the method of high-speed planar polishing by dielectrophoresis effect can effectively improve the polishing efficiency and the workpiece surface flatness by adjusting the electrode layout and optimizing the electrode distribution parameters.