Investigation of the hole-formation process during double-sided through-mask electrochemical machining

Through-mask electrochemical machining has been developed to fabricate hole-array in titanium alloys that are difficult to cut using traditional mechanical machining. The taper angle of hole-array is an important criterion to estimate the quality of machined hole-array. Due to the isotropic nature, the machined holes have taper angles by using through-mask electrochemical machining, and it is still a challenge to reduce these taper angles. In this paper, a double-sided through-mask electrochemical machining process is investigated in order to fabricate hole-array with low taper angle. A model of the double-sided through-mask electrochemical machining is established to simulate the hole-formation process. The simulation results indicate that the electric field of the double-sided through-mask electrochemical machining is beneficial to reduce the taper angles of machined holes. In order to verify the simulation results, experimental investigations of hole-formation are implemented. The experimental results indicate that the sidewall of machined hole could be close to the straight at a certain machining time. Finally, a 6 × 50 hole-array is machined by double-sided through-mask electrochemical machining onto Ti-6Al-4V sheet with thickness 0.5 mm. The maximum taper angle of the hole-array is only 2.52°.