Fabrication of high-density micro holes by upward batch micro EDM

A large number of micro holes are needed for biomedical parts, ink-jet nozzles and micro droplet spraying parts. In this study, an inexpensive machining approach for producing a batch of micro holes is proposed. A set of previously introduced w-EDM mechanisms is employed to horizontally cut the batch micro electrodes precisely. Through the process arrangement, the micro electrodes and workpiece are not unloaded, repositioned and re-corrected until all the tasks are completed. The micro workpiece is clamped onto the specially designed jig and moved above the micro electrodes to perform machining of the mass micro holes by upward batch micro EDM. The entire procedure is carried out on a developed multifunctional tabletop CNC machine tool. An array of 400 through holes of the identical sizes is successfully fabricated on a stainless-steel plate with a thickness of 30 νm by using the modified peck-drilling method. Experimental results confirmed that the proposed approach could accelerate the removal of debris, reduce the occurrence of abnormal discharges and decrease the machining time.