Enhancement of performance of wire electrochemical micromachining using a rotary helical electrode

• A method of WECMM using a rotary helical electrode has been firstly proposed to enhance electrolyte refreshment in the axial depth direction.
• A rotary helical electrode helps the electrolyte to generate an axial velocity, which drags the electrolyte flow from the bottom upwards.
• Electrode rotation is efficient in improving the maximum electrode feedrate and minimizing the slit width.
• Using a rotary helical electrode, the slit width uniformity in the depth direction is enhanced.
• A fir-tree-slot-like structure and a space hollow structure have been fabricated successfully.

The inherent characteristics of wire electrochemical micromachining (WECMM) enable it to be a feasible alternative to machining micro structures with good surface integrity in difficult-to-machine materials. Efficient electrolyte renewal has been proven to be important to the process stability and material removal rate in the machining of high aspect ratio micro structures. This paper proposes a method of WECMM using a rotary helical electrode to enhance electrolyte refreshment in the machining depth direction gap. Simulations of the flow field indicate that when a helical electrode revolves at a high speed, the electrolyte in the machining gap is stirred drastically, and the helical groove on the electrode surface is conducive to electrolytic flow in the axial direction. In addition, a series of experiments verifies that the maximum electrode feedrate and the slit width uniformity in the depth direction are enhanced by using a rotary helical electrode. Finally, two complex micro structures are successfully produced using a rotary helical electrode at a spindle speed of 20000 rpm.