基于介电泳和自激振荡复合效应的抛光方法研究

A novel polishing method, which is based on self-excitation oscillation pulse effect and dielectrophoretic (DEP) effect, is proposed in order to achieve high efficiency,high quality and low cost for polishing cavity surface. The novel method employes self-excitation oscillation generator with a certain fluid structure. During the polishing process, through the self-oscillation generating device, the abrasive flow is transformed from the continuous flow into the vortex ring pulse characteristic flow."sliding friction"of continuous flow on workpiece surface is changed into compound"rolling friction and sliding friction" of the vortex ring pulse flow. At the same time, An inhomogeneous electric field is arranged in the cavity, and one electrodes of the electric field is close to the surface of the cavity. After being polarized, slurry and abrasives moved toward the electrode , which is near cavity surface, its taked part in ploishing cavity surface. the peak pressure of abrasive flow on workpiece surface is increased, so the polishing efficiency of the abrasive flow is improved.the continuous vortex ring pluse of abrasive flow is with an axial symmetry,it can match with the complete curved surface with various curvature, workpiece surface can be completely polishing. the theoretical analysis, numerical simulation and experimental research will be employed, the mechanism of self-excition oscillation pulsed jet polishing will be revealed, the key factors and methods of the quantitative control for the action of the self-excitation oscillation pulse will be studied,the removal characteristics of the workpiece's material will be analyzed. Experimental platform will be builded, the key technology of the application will be explored, a new polishing method for complex curved surface with high efficiency, high quality and low cost will be developed.

为实现型腔表面高效、高质量、低成本的超精密抛光，提出了一种基于介电泳和自激振荡复合效应的抛光方法。抛光过程中，经自激振荡脉冲发生装置，抛光液由连续性流动转变为涡环脉冲特性流动进入型腔，使得磨粒在型腔表面的“滑动摩擦”连续流动转变为复合“滚动摩擦和滑动摩擦”涡环脉冲波流动。同时，型腔内布置一个非均匀电场，电场的1个电极靠近型腔表面，使极化后抛光液和磨粒移向型腔表面附近电极，参与型腔表面抛光，增大磨粒与工件表面峰值压力，提高了磨粒对型腔表面抛光效率。轴向对称的连续涡环脉动流体，能与不同曲率的曲面都保持良好的吻合度，实现无加工死角的材料去除。本项目通过理论分析、数值模拟和实验研究，揭示介电泳和自激振荡复合效应抛光机理，研究复合效应作用定量控制的关键因素和方法，分析工件材料的去除特性，构建加工实验平台，探索该抛光方法应用的关键技术，有望发展一种高效、高质量、低成本的新型型腔表面抛光方法。

面向型腔表面高效、高质量、低成本的超精密抛光需求，开展了基于介电泳和自激振荡复合效应的抛光方法研究。完成主要工作：（1）开展基于自激振荡脉冲特性的磨粒流抛光直径为6 mm 不锈钢管内表面研究，数值计算获得自激振荡腔体的最优结构参数。采用单自激振荡腔室抛光12 h 后，工件内壁的粗糙度Ra 从480 nm 降到50 nm，内壁面轮廓无明显的单向性纹理；14 h 后，内壁有明显镜面效果。而无振荡腔的情况下抛光14 h，内壁表面粗糙度为55 nm，表面存在明显的磨粒流流动的纹路。采用双自激振荡腔室抛光10 h，工件内壁表面粗糙度Ra 从452 nm 降低到42 nm，且有显著的镜面效果。（2）开展基于介电泳效应的磨粒流抛光薄壁陶瓷工件内表面研究，研究表明电极间隙比为２时，ＳｉＣ磨粒具有最好的介电泳效应。陶瓷工件初始内表面粗糙度值Ｒａ 为（２０８±５）ｎｍ ，抛光１０ｈ后，无介电泳效应的磨粒流抛光工件内表面粗糙度值Ｒａ 为５１ｎｍ，有介电泳效应的磨粒流抛光工件内表面粗糙度值Ｒａ 为２３ｎｍ。（3）浸没式自激振荡磨料水射抛光（SSEO-AWJP）氮化硅表面实验。相同条件下，25 min，浸没式磨料水射流抛光的加工区域材料最大去除深度为6.86 um，SSEO-AWJP的加工区域的材料表面去除深度为17.30 um；浸没磨料水射流加工14次后粗糙度Ra稳定在35.7 nm，SSEO-AWJP加工5次后Ra稳定在48.8 nm。（4）开展电极同层布置方式的介电泳平面抛光硅片（SLAE-DEPP）研究。研究结果表明：SLAE-DEPP方式抛光3英寸硅片，抛光6小时后，工件中心处表面粗糙度Ra从初始690nm，下降到1nm以下，工件平面度（RMS值）为0.268 μm，工件材料去除率MRR提高了近27.3%，表面去除均匀，达到镜面，抛光效率和抛光质量均优于传统CMP平面抛光。.项目实施过程，项目负责人获2020年度国家科学技术进步奖二等奖1项；发表期刊学术论文13篇；申请发明专利10项；培养硕士研究生9名（已毕业6名）；