6. Magnetic Effect on High-Speed Electrochemical Discharge (HSECD) Engraving

Machining operation of hard and brittle materials is a challenging task with conventional machining processes. Use of electrochemical discharge machining (ECDM) for machining of hard materials like glass and composites is a promising option due to the efficient cutting ability of the process. But the ECDM process is also suffering from limitations like low material removal rates and heat-affected zones. Material removal rate (MRR) can be increased by providing high-speed rotation of the tool electrode as high-speed ECDM process showed promising results for an increase in MRR. Further improvement in ECDM can be done by using magneto hydrodynamic (MHD) force on the machining zone. With MHD force more stable gas film can be obtained which will increase the thermal discharge. MHD force also increases the cooling of the surface around the machining zone which reduces the heat-affected zone (HAZ) and increases MRR. In this research work machining zone of high-speed electrochemical discharge engraving process (HSECD engraving) is exposed using magnetic elements of 3000 gauss capacity. Performance of HSECD engraving process is studied with and without magnetic field using different process variables, like voltage, tool rotation speed and feed rate. The results of this work show that the performance of the HSECD engraving process is improved with the use of the magnetic field. It is observed that MRR is increased by a maximum value of 0.17 mg/min and HAZ is decreased by a maximum value of 16 µm when magnetic field is applied.