Flow Behaviour of Bidisperse MR Polishing Fluid and Ball End MR Finishing

Bidisperse MR polishing fluid samples has been prepared with varying percentage of small sized magnetic contents of carbonyl iron powder (CIPs) HS grade within same vol% of total magnetic contents. Magnetorheological behaviours of bidisperse MR polishing fluid for comparison with monodisperse MR polishing fluid using physica MCR-301 rheometer is presented in this paper. The flow behaviour of MRP fluid has been evaluated by steady state rheograms at different magnetic field strength. The yield shear stress and viscosity of bidisperse MRP fluid for all experiments were found maximum at 16 vol% CIPs CS grade, 4 vol% CIPs HS grade, 25 vol% abrasives and 55 vol% base fluid. The results indicate that the yield shear stress and viscosity of bidisperse MRP fluid has been found improved as compare to monodisperse MRP fluid for all magnetic field strength. The morphology of the prepared samples has been studied using scanning electron microscope. After characterization, the experiment was performed with bidisperse MRP fluid on mild steel work-piece using ball end MR finishing tool for 30 minutes with a set of given machining parameters. Percentage reduction in surface roughness (%ΔRa) was calculated and found superior results as compared to existing one.