The effect of voltage on accuracy in electrochemical micromachining under two-tone sinusoidal signal

Electrochemical micromachining (ECMM) is a non-traditional technology in the field of machining, which has excellent machining quality. Ultra short pulse power supply is widely used in electrochemical micro machining, and shortening the pulse width is the only effective strategy to improve machining accuracy. But it is costly, not suitable for practical production, also restricts the development of other signals. To solve this problem, this paper proposes using a two-tone sinusoidal signal instead of ultra short pulses, and establishes a three-dimensional model of electrochemical machining based on finite element method. The influence of input voltage on the surface contour evolution of the anode workpiece is analyzed, and the distribution law of input voltage on the inter electrode electrolyte potential and current density is also analyzed. Theoretical analysis shows that as the amplitude of the input signal voltage in the circuit gradually decreases, the contour formed on the surface of the anode workpiece becomes shallower, and the speed of material decomposition tends to slow down. The experimental results of micro hole processing also showed that with the decrease of input voltage, the processing accuracy significantly improved, reaching the sub-micron level. In addition, when machining microstructures on high-temperature nickel chromium alloys that are difficult to cut, the same level of superior machining accuracy can be achieved. • We use two-tone sinusoidal signal instead of ultrashort pulse to establish a three-dimensional model of electrolytic machining and study the mechanism of input voltage to reduce the machining gap. • We systematically investigated how input voltage influences the electric field distribution and current density, demonstrating that a controlled reduction in voltage significantly improves machining accuracy. • We use this technology to machine the microstructures on 5-μm pure nickel sheet and hard-to-cut super alloy plates, and improve the machining accuracy to the nanometer level.