Small hole fabrication through additively manufactured CuCr1Zr electrode during EDM of a novel Haynes 25 superalloy

Abstract

Present work proposes an extensive experimental investigation to evaluate the machinability of Haynes 25 work piece with additively manufactured CuCr1Zr (prepared through selective laser melting process), pure copper and graphite electrodes, in view of producing small holes of diameter 3 mm. Prior to machinability investigation, material characterization studies in terms of energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) analysis along with several other mechanical as well as physical properties such as density, microhardness, tensile strength, electric conductivity and thermal conductivity, are carried out for both the electrodes. Outcomes of critical process parameters viz. current (I), voltage (V), pulse on time (Ton), duty factor (τ), and flushing pressure (Fp) are studied on performance measures such as material removal rate (MRR), electrode wear ratio (EWR), specific energy consumption (SEC), surface roughness (Ra), and radial overcut (ROC). The EDMed surface is carefully analysed by a field emission scanning electron microscopy (FESEM) study. It is observed that additively manufactured CuCr1Zr electrode is proficient enough to produce parts with greater accuracy, improved surface finish with least amount specific energy consumption, thus saving cost and time during machining. The ideal level of cutting parameters are identified, validated with confirmative experiment with an average error of 2.79 percentages to produce precise accurate EDMed parts. This work delivers an energy efficient as well as cost effective machining strategy to produce precise and accurate small holes for EDMed applications, thus paving way for productivity of the process.

Keywords

• Electrical discharge machining (EDM)
• Haynes 25 superalloy
• Fabrication of small holes
• Additively manufactured CuCr1Zr electrode
• Specific energy consumption (SEC)