Fabrication of microelectrode with large aspect ratio and precision machining of micro-hole array by micro-EDM
Fabrication of microelectrode with large aspect ratio and precision machining of micro-hole array by micro-EDM
复制标题
大深宽比微电极的制作及微电火花精密加工微孔阵列
DOI：
10.1016/j.jmatprotec.2019.01.009
复制
发表时间：
2019-06-01
影响因子：
6.3
通讯作者：
Zhu, Guozheng
中科院分区：
文献类型：
--
作者：
Li, Zhengkai;Bai, Jicheng;Zhu, Guozheng
微细电火花加工(Micro-EDM)对微小孔、微凹窝、微通道等微细结构具有良好的加工能力。本研究对直径小于50微米的微孔阵列精密微细电火花加工进行了探索。研制了一种新型的有源供丝-电火花磨削(AS-WEDG)装置，目的是减小磨削位置的丝材波动，提高微电极的长径比。利用研制的AS-WEDG器件，成功地制作了平均直径为40.3微米、长径比为49.6的微电极。对于RC型脉冲电源，研究了开路电压和电容对单个微孔加工质量的影响。通过分析微电极的磨损特性，在微孔阵列加工过程中采用了等长补偿策略。同时，为了消除累积补偿误差的不利影响，基于CCD视觉系统对微电极的轴向位置进行周期性调整。根据喷墨喷嘴的要求，在厚度为50µm的不锈钢上加工了256个(2×128)微孔阵列，平均直径为46.13微米。微孔阵列的入口和出口的标准偏差分别为0.44微米和0.68微米，从而保证了微孔阵列的直径一致性。此外，通过静态打印试验验证了加工后的微孔阵列能够产生均匀的液滴速度，具有良好的工作性能。
Micro electrical discharge machining (micro-EDM) exhibits good processing capability to miniature structures such as micro-holes, micro-dimples, micro-channels and so on. In present study, the precision micro-EDM of micro-hole array with diameter less than 50 mu m was explored. A novel active supplying wire-electro discharge grinding (AS-WEDG) device was developed aiming to reduce the wire fluctuation at grinding location and improve the aspect ratio of microelectrode. With the developed AS-WEDG device, the microelectrode of 40.3 mu m in average diameter and 49.6 in aspect ratio was successfully fabricated. For RC-type pulse generator, the effects of open-circuit voltage and capacitance on machining quality of single micro-hole were concerned. By analyzing the wear characteristics of microelectrode, the constant length compensation strategy was adopted during the micro-hole array machining process. Meanwhile, in order to eliminate the adverse effect of cumulative compensation errors, the periodic adjustments of axial position of microelectrode were involved based on the CCD vision system. According to the requirement of inkjet nozzle, array of 256 (2 x 128) micro-holes with average diameter of 46.13 mu m was machined on a 50 mu m thick stainless steel. The diameter consistency of micro-hole array was assured by showing standard deviation of 0.44 mu m and 0.68 mu m at entrance and exit side, respectively. In addition, the static printing test verified the good working performance of as-machined micro-hole array by generating uniform droplet velocities.