Enhancement of mass transport in wire electrochemical micro-machining by using a micro-wire with surface microstructures

Efficient electrolyte refreshment has been proved to be significantly important in wire electrochemical micro-machining (WEMM). Surface microstructures can improve the hydrophilicity of most metallic surfaces, resulting in an increased adhesion energy between the liquid and solid surface. This paper approached a method of WEMM using a wire electrode with surface microstructures to enhance the efficiency of mass transport in the machining area. Microstructures were fabricated on a 50-μm-diameter tungsten wire using nanosecond laser machining. A series of laser-machining experiments were carried, and spike-like microstructures with various sizes were successfully fabricated on the wire electrode via adjusting the laser fluence. Comparative experiments of WEMM using a smooth electrode and laser-machined ones were performed. The experimental results revealed that the wire electrode with surface microstructures exhibited higher hydrophilicity than the smooth one. Using a wire electrode with surface microstructures in WEMM with tool axial vibration could effectively enhance the mass transport efficiency, resulting in improving machining efficiency and homogeneity of machined slit. The maximum feed rate able to be applied increased 2.5 times, and the standard deviation of the machined slit decreased from 1.6 to 0.5 μm.