In the last decade, the Electrochemical Discharge Drilling (ECDD) has emerged as an alternative to conventional laser ablation used to create blind and through-holes in non-conductive materials such as fused silica, quartz, and glass workpiece. The initial tool electrode and workpiece (T-W) gap play a vital role in microhole formation and tool wear. Therefore, an experimental investigation into the effect of the initial T-W gap with different machining time and electrolyte concentrations on the blind microhole formation in the glass and tool wear in the velocity-feed ECDD is reported. The microholes having superior surface quality and lower overcut were fabricated with KOH electrolyte and lower concentration. A novel numerical model based on inverse heat flux reduction for varying initial T-W gaps was studied for the first time. The obtained experimental results were compared to the numerical results obtained with the finite element based numerical simulations. The opening size of the microholes increased up to a critical T-W gap and then decreased with a further increase in the gap. The critical gap is found to be 20 µm and 10 µm for NaOH and KOH electrolyte, respectively. The depth of the microholes was the maximum at a zero-gap condition; however, the tool wear was severe. The highest average depth of 175 µm was obtained at 30 wt% NaOH for the machining time of 60s. Tool wear tends to be decreasing with increasing the T-W gap. Least average tool wear of 9 µm was observed for 20 wt% KOH electrolyte for machining time of 60s. The experimental results indicated that the conventionally used gravity-feed mechanism is not suitable from the tool wear point-of-view, and a particular initial T-W gap should be maintained during the ECDD process. The T-W gap between 10-30 µm for the NaOH electrolyte and 5-20 µm for the KOH electrolyte is recommended.

在过去的十年中，电化学放电钻孔（ECDD）成为了传统激光烧蚀的替代方法，该技术用于在非导电材料（例如熔融石英，石英和玻璃工件）上形成盲孔和通孔。最初的工具电极和工件（TW）间隙在微孔形成和工具磨损中起着至关重要的作用。因此，对不同加工时间和电解质浓度下的初始TW间隙对玻璃中盲孔形成以及速度进给ECDD中工具磨损的影响进行了实验研究。用KOH电解质和较低的浓度制备具有优异的表面质量和较低的过切的微孔。首次研究了基于逆热通量减少的不同初始TW间隙的新型数值模型。将获得的实验结果与基于有限元数值模拟获得的数值结果进行比较。微孔的开口尺寸增大到临界TW间隙，然后随着间隙的进一步增大而减小。对于NaOH和KOH电解质，发现临界间隙分别为20μm和10μm。在零间隙条件下，微孔的深度最大。但是，工具磨损严重。在60％的加工时间内，使用30 wt％的NaOH可获得175 µm的最高平均深度。随着TW间隙的增加，刀具磨损趋于减少。对于20 wt％的KOH电解质，在60s的加工时间内观察到的最小平均工具磨损为9 µm。实验结果表明，从刀具磨损的角度来看，常规使用的重力进给机构是不合适的，在ECDD过程中应保持一个特定的初始TW差距。建议NaOH电解液的TW间隙为10-30 µm，KOH电解液的TW间隙为5-20 µm。