Fabrication of 3D microstructures in glass by direct writing electrochemical discharge machining

Abstract

ABSTRACT The formation of 3D copper-filled microstructures in glass using direct writing electrochemical discharge machining (ECDM) and electrodeposition techniques is presented. Single-row stainless steel tool electrodes having tip sizes of 150 µm were made by wire electrodischarge machining (W-EDM). Tool wear mechanism and the tip size correction of the worn-out tools were investigated. Significant tool wear was observed after 5 ECDM repetitions of the tool electrodes involving drilling and milling operations. Due to the high temperature generated in the ECDM process, there is significant erosion in the tool electrodes, and the tip heights of the electrodes became non-uniform. Thus, the single-row tool electrode became non-reusable in the ECDM process. Therefore, the electrochemical dissolution (ECD) method was used to correct the tip dimension and make the tool reusable for the ECDM process. After the ECD correction, the obtained tip size was close to the original size of 150 µm with <5% inter-tip size variation. Up to two-cycle of ECDM and ECD size correction was performed; thus, enhanced reusability of the single-row tool electrodes was demonstrated. The 3D structures were metallized using the copper electroplating method. DC measurement of the microstructures showed good electrical connectivity with an ohmic nature.