Electrochemical Micromachining of Copper Alloy through Hot Air Assisted Electrolyte Approach

Abstract

The industries like automobile, electronics, medical and biomedical sectors provide scope for various types of micro products/features made up of copper material. Due to the higher ductility of copper the electrochemical micro machining (EMM) is a prominent technique owing it’s no tool wear, high accuracy, burr free and non-contact machining surface. Although enhancing of EMM performance is significant work in the micro components manufacturing industry. Hence, in this present work the hot air is mixed with aqueous citric acid (C6H8O7) electrolyte (HAME) to machine high aspect ratio micro-holes (HAR micro-hole) and the results are compared with the dry air mixed electrolyte (DAME). The process parameters such as machining voltage (Mv), Duty cycle (Dc), and electrolyte concentration (Ec) are taken into account in evaluating the machining performance. The electrolyte temperature (Et) and frequency are kept at a constant level as 36 ± 1°C and 85 Hz respectively. The machining performances are estimated by means of material removal rate (MRR), overcut (OC) and taper angle of the HAR micro hole (TAHAR-micro-hole).The MRR shows 1.43 times improvement for HAME at the parametric combination of 20 g/L, 13 V, and Dc at 90% and reduced OC by 30.4% over DAME. The TAHAR-micro-holes are found to be 21.67° and 28.19° for the DAME and HAME respectively for the above parametric combinations. At parameters combination of 30 g/L, 13 V, and 90%, the MRR shows 2.87 times higher MRR compared to DAME. Furthermore, the use of citric acid as an electrolyte and mix of hot air contributes for higher MRR and reduced OC.The field emission scanning electron microscope (FESEM) analysis is done to understand the effect of hot air mixed electrolyte on the surface topography and inner machined surfaces of a micro-hole.