Fabrication of an array of precision nozzles by through-mask electrochemical micromachining

Through-mask electrochemical micromachining (EMM) has been employed to fabricate an array of precision nozzles in metal foils for application in inkjet printer heads. An experimental investigation has been conducted to determine the optimum dissolution condition that provides nozzles of desired shape and smooth surfaces. Dissolution below the limiting current yielded irregularly shaped nozzles with extremely rough surfaces while nozzles of desired shape with microsmooth surfaces were obtained by dissolving at the limiting current plateau or at higher voltages. Use of pulsating voltage (current) provided a better control over the nozzle fabrication process because of the possibility of applying high instantaneous current density while maintaining a low average current which is desirable for thin-film processing. The results of the present study demonstrate the feasibility of employing a through-mask EMM process for fabricating high precision nozzles in copper and stainless steel foils.