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In the current scenario, the advanced industries are using highly sophisticated types of machinery. These types of machinery use numerous cylindrical components made with superior materials and technology. For obtaining the nano-level finished interior cylindrical surface with high accuracy and high production rate, a newly developed rotational magnetorheological honing (R-MRH) process is employed on the cylindrical objects. This process is applicable in internal nano-finishing of cylindrical molds, hydraulic and pneumatic valves, aerodynamic bearings, gears, cylindrical barrel, and cylinders used in medical devices, etc. In the present work, the cylindrical workpiece is also made rotational in the reverse direction of the MRH-tool rotation unlike the existing MRH process. The rotating motion of the workpiece cylinder caused an increment in relative motion of the active abrasive particles against the interior surface of the workpiece cylinder. The effect of the rotational speed of the workpiece cylinder along with movements of the MRH-tool on change in surface roughness is investigated theoretically and experimentally in this work. Theoretically, it is found that the simultaneous motions of tool and cylindrical workpiece in the opposite direction to each other increase the finishing rate. To validate the theoretically increased finishing rate due to the rotating cylindrical workpiece, and to examine the effect of the rotational motion of the cylindrical workpiece on finishing performance, the experiments are conducted with the R-MRH process. The reduction in surface roughness is found as 71.71% in 60 min with the existing MRH process for the stationary cylindrical workpiece, whereas it is reduced to 83.83% in only 40 min with the R-MRH process for the rotational cylindrical workpiece. The significant change in surface roughness value with reduced finishing time validates the improved efficacy of present R-MRH process for its more utility in industries.

Permanent mould dies are used for various plastic injection moulding products. Most of the mould cavity is blind and henceforth difficult to finish. In this study, a novel magnetorheological fluid-based finishing process using permanent magnet tools has been developed for nano-finishing of cylindrical blind hole surfaces. Tools to finish the internal and flat-bottomed surfaces of the cylindrical blind hole are developed. The finishing performance of both tools is evaluated for finishing ferromagnetic material used in dies. The material of the die is P20 tool steel having 41 HRC hardness. Response surface methodology using a central composite design technique has been utilized for the plan of experiments and analysis of significant process parameters on the percentage change in surface roughness using newly developed tools. During finishing the internal cylindrical blind hole surface, the process parameters like rotational speed, reciprocation speed and abrasive mesh size are found to be significant. However, during flat-bottomed surface finishing of cylindrical blind hole workpiece, rotational speed, abrasive mesh size and abrasives volume percentage are found to process significant parameters. Experimentation at optimized parameters results in the final surface finish of 83 nm on internal cylindrical surface and 93 nm on the flat-bottomed surface of cylindrical blind hole workpiece.

The particles used in magnetorheological polishing (MRP) fluid are the key components of the magnetorheological (MR) finishing processes. The rotational magnetorheological honing (R-MRH) process is recently developed as a highly productive MR finishing process which is used for finishing the internal surface of the industrial cylindric components. The involvement of micron-sized abrasive particles of MRP fluid in the finishing operation results in the invisible observation of the finishing mechanism which enables the urge of analyzing the motion of the particles during the present R-MRH process. Therefore, the effect of motions of the MRP-fluid’s particles is analyzed for nano-finishing performance on the inside surface of the cylindric workpieces. The motions performed by active abrasive particles on the inside surface of the rotating hollow cylindric workpiece cause a higher finishing rate. The effects of particle motions on the reduction in surface roughness and improvement in surface morphology confirm the usefulness of the R-MRH process. The surface finish with the effect of the particles' motions of the MRP-fluid in the R-MRH process on the stationary workpiece’s inner surface is achieved upto 100 nm from 420 nm of the initial ground surface in 60 min of finishing. Whereas, the same aforementioned surface of the rotating workpiece is finished upto 50 nm from the same initial ground surface in only 40 min of finishing with the effect of the particles' motions of the MRP-fluid. The improvement in the surface finish is also noticed through the scanning electron micrographs in this work. The significant change in surface finish obtained in experimentations confirms the integrity of the analytical study conducted for understanding the effects of motions of particles while finishing with the R-MRH process.