Modeling and simulation of surface roughness in ultrasonic assisted magnetic abrasive finishing process

Abstract

An ultrasonic assisted magnetic abrasive finishing (UAMAF) is a hybrid finishing process. In UAMAF, ultrasonic vibrations are introduced into the finishing zone of magnetic abrasive finishing (MAF) process to finish the workpiece surface more efficiently as compared to MAF in the nanometer range. In the present work, a model of surface roughness during UAMAF process has been presented. The model assumes that the instantaneous rate of change of surface roughness is proportional to the material removal rate (MRR) and the amount of irregularities present on the surface. A model of MRR was presented, considering it to be attributed to two simultaneous and independent phenomena—a steady state material removal and a transient material removal. The MRR model has further been used to model the instantaneous surface roughness during finishing. The surface roughness model not only incorporates the effect of initial surface roughness value but also assimilates a critical surface roughness value below which no reduction in roughness is possible. The constants included in the modeling are predicted by using an inverse method. A simulation of 3-D surface roughness profile has also been presented to visualize the effect of finishing numerically. The developed model predicted the surface roughness in UAMAF as a function of supply voltage, working gap, rpm of the electromagnet, amplitude and frequency of ultrasonic vibration, hardness and initial surface roughness of the workpiece. The predicted value shows a good agreement with the experimental observation with a maximum deviation of ±7.35%. The model affirms that an exponential correlation exists between instantaneous surface roughness value and finishing time during finishing.