MEMS-Based Batch-Mode Micro-Electro-Discharge Machining using Microelectrode Arrays Actuated by Hydrodynamic Force

This paper reports a batch-mode micro-electro-discharge machining technique that is enabled by the actuation of the suspended microelectrode arrays fabricated on the workpiece using the flow of the machining fluid. The electrode devices are microfabricated to be the double-layer construction that has 25-mum-thick copper electrodes with custom patterns on the bottom of the 18-mum-thick planar structures suspended above the workpiece surfaces. The built-in capacitance of the electrode device is utilized to construct a resistance-capacitance pulse generation/timing circuit. The suspended planar electrodes are advanced into the workpiece material with the hydrodynamic force while sustaining high-frequency discharge pulses, removing the workpiece material. Arrays of microstructures with 26-mum depth were machined in stainless steel using the machining voltage of 90 V. The dynamic behavior of the built-in capacitance of the double-layer electrode devices with the actuation was experimentally evaluated.