Vibration-assisted electrochemical discharge drilling method for microholes without recast layer

During electrochemical discharge drilling (ECDD), tool electrode bending and debris accumulation easily lead to secondary discharges and instability, which will affect the removal of recast layers. To improve the stability and processing quality of the machining process, a novel vibration-assisted electrochemical discharge drilling (VAECDD) method has been proposed. In this method, vertical vibrations are applied to the workpiece, causing pulsating fluctuations in the pressure and velocity of the working fluid, thereby carrying away the debris. This ensures adequate and uniform electrochemical reactions to remove the recast layer. The simulation and experiments were carried out with different vibration frequencies and amplitudes. The simulation results show the vibration frequency has a more obvious influence on the transient pressure. The experiment shows that the machining accuracy, efficiency, and the removal effect of recast layers all show an upward trend with the increase of vibration frequency, while first increasing and then decreasing with the increase of vibration amplitude. When the vibration frequency and amplitude are 40 kHz, 0.7 μm, the removal rates of recast layers are above 97%. It is an effective machining approach for high-quality, accurate, and efficient of film cooling holes.