Investigation into micro slotting of Cu-based shape memory alloy via µ-ECM using ethylene glycol mixed aqueous NaCl electrolyte

Micro-Electrochemical Machining (µECM) presents significant promise as a future micromachining process offering higher machining rates, improved precision and the ability to work with a wide range of materials. Cu-based shape memory alloys (SMAs) have exceptional properties that make them quite difficult to machine using traditional techniques. In this investigation a new electrolyte solution consisting of ethylene glycol (EG) and NaCl has been explored while attempting µECM of Cu-SMA. The Cu-based shape memory alloy used consists primarily of Cu-53.19%, Zn-41.50%, and 5.2% other elements. Four different parameter combinations selected based on pilot experiments were used for the main experimentation conducted in four sub-sets. The influence of micromachining parameters including machining voltage, electrolyte concentration and micro-tool feed rate on µECM characteristics such as material removal rate (MRR) and surface roughness (SR) during micro-slot formation has been investigated. With the identified optimum parameters, a high-quality micro-slot was successfully machined on Cu-based shape memory alloys achieving a material removal rate of 0.323 mg/min and surface roughness of 0.384 μm. The investigation demonstrated that an ethylene glycol electrolyte containing NaCl is more suitable for µECM of micro-slots offering superior surface integrity and shape accuracy compared to a water-based electrolyte.