Study on influencing law of processing parameters in multi-aperture hole-making process with electro-hydraulic jet

Electro-hydraulic drilling has the advantages of high surface quality and no recast layer or microcracks. In the drilling, the optimization of the processing parameters has a significant influence on the hole diameter and quality. In this paper, the dynamic processing process of electro-hydraulic drilling is simulated and analyzed by using COMSOL software. The influences of the key processing parameters such as voltage, electrolyte conductivity and feed rate on the size of micro-holes are analyzed. Through the design of a set of drilling experiments, the high-precision straight holes with the diameters ranging from 0.5 mm to 1.0 mm were successfully drilled. The experimental results show that the hole diameter is positively correlated with the voltage and electrolyte conductivity, and negatively correlated with the feed rate. By optimizing the processing parameters, the high-quality micro-holes with a surface roughness of 1.28 μm were obtained. When the ratio of the target hole diameter to the outer diameter of the capillary exceeds 1.8 times, it will significantly affect the geometric accuracy (roundness and taper) of the hole. By increasing the diameter of the capillary, the roundness of the target hole is greatly improved.