Geometrical shape analysis of through-hole formation in tungsten by Electrochemical jet drilling

This article presents a 2D axisymmetric numerical model to predict the geometric profiles of micro-features in tungsten created by electrochemical jet drilling (EJD). The model incorporates nozzle feeding and simultaneously solves fluid dynamics, electric field, and material deformation. Without feeding, the model predicted a depth of 280 mu m after 25 s of drilling at 50 V and 500 mu m SOD. Introducing a 10 mu m/s feed rate increased the depth to 320 mu m. Numerical predictions showed strong agreement with experiments, within a +/- 5 % error. Increasing jet velocity from 9.6 m/s to 11.4 m/s improved depth by 13 % and reduced hole entrance diameter by 30 % after 8 min of drilling at 50 V and 400 mu m SOD. The mechanism of improved material removal at higher jet velocity is explained. Using the optimized jet velocity, micro-through holes were successfully drilled in 2.1 mm thick tungsten, achieving a maximum aspect ratio (AR) of 3.4.