Analysis of surface finishing mechanism in a newly developed rotational magnetorheological honing process for its productivity improvement

In modern industries, nano-finishing of a part with high precision and dimensional accuracy is a crucial requirement. The finished surface of an industrial component improves the features such as appearance, resistance to abrasion which guards against wear, corrosion and chemical damages of the surfaces. A permanent magnet based rotational magnetorheological honing (R-MRH) process is developed for improving the productivity of internal surface finishing of the ferromagnetic cylindrical workpieces. In this process, the motion of the cylindrical workpiece is also simultaneously performed in opposite direction of the rotational motion of the magnetorheological honing tool unlike to the existing conventional as well as the magnetorheological honing processes. Finishing the internal surface of the cylindrical workpieces through R-MRH process leads to more saving in power consumption, improvement in productivity and increase in its functional applicability as compared to the existing magnetorheological honing technique. The normal magnetic force acting on the abrasive particle through the magnetic carbonyl iron particles is responsible for the indentation of abrasive onto the finishing surface. As the indented abrasive particle performs relative motion against the finishing surface of the workpiece, the ploughed materials get removed in the form of microchips due to the shear force acting on it. In the present work, workpiece rotation in the opposite direction of the MRH tool rotation results in increased relative speed and number of interacting abrasive particles with the fresh edge. The increased relative speed of the indented active abrasive particles causes a higher rate of wear of ploughed material. This results in a higher production rate and finishing capability. For the developed R-MRH process, a model of surface roughness has been proposed. The developed model has been experimentally validated with the different sets of finishing cycles. The scanning electron microscopy is performed to have a better understanding of finished surface patterns. The theoretically calculated surface roughness and experimentally obtained surface roughness is compared and both the values are found with the agreement within the error of 3.33-5.92%. The present developed R-MRH process is found to be suitable for nano-finishing of the internal surface of cylindrical components in reduced finishing time.