In modern high-performance machinery, parts which are highly finished and dimensionally accurate play a vital role. Surface finish enhances characteristics like wear, corrosion, pitting, and oxidation resistance of the surfaces. A novel magnetorheological polishing process using permanent magnets is developed to finish the internal cylindrical and bottom surfaces of the blind hole cylindrical workpiece. The process is capable of finishing the internal cylindrical and flat bottom surfaces of tubular and nontubular-shaped blind hole workpiece. Finishing of blind hole surfaces finds extensive application in dies and automotive components such as automobile actuators, cylinder body, valve seats, etc. In this study, two different tools for finishing the internal and flat bottom surfaces of blind hole cylindrical workpiece have been developed. The causal factor for material removal in the form of microchips is abrasive wear. The present study focuses on the calculation of forces acting on abrasive particles and mathematical modeling and simulation of the surface roughness. The performance of both newly developed tools for finishing the cylindrical blind hole mild steel workpiece is evaluated. After 275 finishing cycles, the Ra values improved by 55.2% in the internal cylindrical ferromagnetic workpiece and by 53.33% after 75,000 cycles on the flat surface of ferromagnetic blind hole workpiece. The theoretical and experimental values of the surface roughness are found to be consistent. The experimental surface roughness values of blind hole internal cylindrical surfaces are within 6.26% of the theoretical values, whereas in finishing the blind hole bottom surface it is found within 7.9% of the theoretical values.

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.

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