掩膜电解加工是一种高效率、大规模加工微结构的特种加工方法。然而,由于电流分布的边缘效应,在微结构的掩膜电解加工过程中往往存在着严重的加工尺寸不一致问题。针对这一问题,本文提出了一种移动阴极式掩膜电解加工方法。首先,利用COMSOL有限元分析软件对微沟槽阵列掩膜电解加工过程中的电流分布和阳极轮廓形状进行了数值仿真。仿真结果表明,相对于常规阴极结构的掩膜电解加工,采用移动阴极结构的掩膜电解加工方法能够获得尺寸更加均匀的微沟槽阵列结构。其次,在数值仿真的基础上,开展了掩膜电解加工实验研究。实验结果表明,移动阴极式掩膜电解加工方法能够有效地改善微沟槽阵列加工的尺寸均匀性。相对于常规阴极结构的掩膜电解加工过程,移动阴极式掩膜电解加工微沟槽阵列的均匀性提高了68.3%,并且随着阴阳极间距的增大,微沟槽深度不均匀度呈现出先减小后增大的趋势。随着阴极宽度的增大,微沟槽深度不均匀度逐渐增大;随着阴极移动速度的增大,微沟槽深度不均匀度逐渐减小,仿真与实验结果趋势一致。

As a typical surface texture, microgrooves have broad prospects in the fields of mechanical engineering, bio-medicine, new energy and efficient heat dissipation of electronic products. Through-mask electrochemical micromachining (TMEMM) is widely used in the fabrication of micro-structures because of high processing efficiency and no residual stress. However, due to the edge effect of current distribution, there is often a serious dimension discrepancy problem in electrochemical machining of micro-structures. In order to weaken the influence of edge effect on the uniformity of microgrooves, the method that TMEMM with a moving cathode is presented. The current distribution in the electrochemical machining is constantly changed by the movement of the cathode. Thus, the uniformity of the micro-structure is improved. The method is studied through the combination of simulation and experimental verification. Firstly, the electrochemical machining process of TMEMM was analyzed theoretically. The theoretical analysis results show that the depth of electrolytic etching is proportional to the current density of electrolytic machining. To change the uniformity of the electrochemical machining, the most important thing is to improve the uniformity of the current distribution. On this theoretical basis, the current distribution and anodic contour of microgroove array during TMEMM are simulated by using the COMSOL finite element analysis software. The simulation results indicate that, compared with the conventional TMEMM, the TMEMM with moving cathode can obtain the microgrooves array with more uniform size. Secondly, on the basis of numerical simulation, the TMEMM experiment was carried out. The experimental results indicate that the TMEMM method of moving cathode can effectively improve the size uniformity of microgroove array. It can be observed by microscope that the microgroove array obtained by TMEMM with a moving cathode had good structural morphology and higher uniformity. Compared with conventional TMEMM, the uniformity of TMEMM with moving cathode has been improved by 68.3%. At the same time, under different experimental conditions, the trend of unevenness of microgroove array was calculated. With the increase of the distance between the cathode and anode, the microgroove depth heterogeneity showed a tendency of first decreasing and then increasing, when the distance between anode and cathode is about 1.3 mm, the unevenness of microgroove array reaches the minimum point. With the increases of cathode width and cathode speed, the depth inhomogeneities of microgroove increase and decrease gradually, respectively. The simulation results are basically consistent with the experimental results. It can be seen that the TMEMM with the moving cathode method can greatly improve the size uniformity.