Fluid drag, ball interaction and gyroscopic effects in magnetic fluid grinding

Abstract

Experimental studies of the magnetic fluid grinding process have previously established that it is an abrasive grinding process. Sliding between the material being ground (for example, a ceramic ball being finished) and the grinding surface occurs because of viscous drag forces and torques acting on the ground material as it is driven through a magnetic liquid. Mechanical models of the process have qualitatively predicted trends in grinding rates resulting from changes in operating conditions, but have not been quantitatively accurate. This paper establishes that the reason is inaccurate modelling, in the previous work, of the fluid drag forces and torques. Improved modelling now gives accurate prediction of the motions in a grinding cell. Interactions between balls travelling in a train and gyroscopic effects are also reported on; they are of secondary importance in influencing slip magnitude at the grinding surface but do provide mechanisms for randomizing ball motions.