There are still some problems in the electrochemical machining (ECM) of micro-deep holes with a diameter of 100–200 μm. For example, it is difficult to prepare an insulation layer on the outer sidewall of a micro-hollow electrode. Under the influence of high-pressure liquid flushing and bubble tearing in a small machining gap, the prepared insulation layer is easily damaged/fallen off. And the micro-hollow part of the electrode is also easily blocked in the preparation. In order to solve the above problems, a novel method for preparing an insulation layer by asymmetric-timed bipolar electrophoretic coating in an aqueous epoxy acrylic solution was presented. In this method, the liquid-supplied technique that the interior of the micro-hollow electrode was completely filled up with the still deionized water, was ingeniously combined with the repeated and alternating process, in which the positive electrophoretic coating undergoes for a longer period of time and the negative electrophoretic stripping undergoes for a shorter period of time. Through simulation and orthogonal tests, the process parameters of the electrophoretic coating were optimized. Comparative verification experiments were conducted using the prepared sidewall-insulation electrodes. The surface morphology, the electrical insulating property, the size and morphology of the fabricated holes, and the surface morphology of the electrodes after machining were used as indicators for comparing and analyzing the performance of the insulation layers. Finally, a micro-deep hole array was machined on a stainless steel 304 plate with a thickness of 500 μm. The typical hole diameter of the inlet and outlet is about 168 μm. Compared to the machined holes of the sidewall-insulation electrodes prepared by the traditional electrophoretic coating method, the taper is reduced by more than 60%, and the surface quality is improved by about 30%. The results show that the sidewall-insulation layer prepared by the method proposed in this paper has higher compactness, uniformity, durability and consistency, and its performance meets the special requirements of the micro ECM for the electrode sidewall-insulation layer.

在直径为100-200μm的微深孔的电化学加工（ECM）中仍然存在一些问题。例如，很难在微空心电极的外侧壁上制备绝缘层。在较小的加工间隙中，在高压液体冲洗和气泡撕裂的影响下，准备的绝缘层很容易损坏/掉落。并且在制备中电极的微空心部分也容易被堵塞。为了解决上述问题，提出了一种在环氧丙烯酸水溶液中通过不对称定时双极电泳涂层制备绝缘层的新方法。在这种方法中，液体供应的技术是在微空心电极的内部完全充满去离子水，巧妙地将其与重复和交替的过程相结合，其中正电泳涂层经历更长的时间，而负电泳剥离经历更短的时间。通过仿真和正交试验，优化了电泳涂层的工艺参数。使用制备的侧壁绝缘电极进行了比较验证实验。将表面形态，电绝缘性能，所制造孔的尺寸和形态以及加工后电极的表面形态用作比较和分析绝缘层性能的指标。最后，在厚度为500μm的不锈钢304板上加工微深孔阵列。入口和出口的典型孔直径约为168μm。与通过传统的电泳涂覆方法制备的侧壁绝缘电极的加工孔相比，锥度降低了60％以上，表面质量提高了约30％。结果表明，采用本文提出的方法制备的侧壁绝缘层具有更高的致密性，均匀性，耐久性和一致性，其性能满足微型ECM对电极侧壁绝缘层的特殊要求。