A study on the equilibrium condition of the oxide layer in ELID grinding

摘要

Grinding with electrolytic in-process dressing (ELID) is gaining popularity for machining hard and brittle materials due to its excellent surface generation capabilities. However, till date, no fundamental investigation on the formation and erosion of the oxide layer deposited on the wheel has been conducted. In this study, ELID grinding experiments are conducted and it is found that the electrolytic current attains a steady value. The dressing current is controlled by the oxide layer thickness, which in turn, is determined by its formation during electrolytic dressing and erosion during grinding. When these formation and erosion rates reach equilibrium, a steady layer thickness is achieved, producing steady current. The phenomenon is theoretically investigated by formulating electrolytic dressing to find oxide formation per wheel rotation. Oxide erosion, per wheel rotation, during grinding is formulated and the solution of these formulations for successive wheel rotations, gives the change in dressing current with grinding time. The theoretical results show that a constant current value is achieved due to equilibrium of oxide formation and erosion rates and these are substantiated by experimental findings.