Experimental analysis of magnetorheological finishing of blind hole surfaces using permanent magnet designed tools

• Published in: Journal of the Brazilian Society of Mechanical Sciences and Engineering Vol. 42; no. 3
• Main Authors: Sirwal, Sohaib Ahmad, Singh, Anant Kumar, Paswan, Sunil Kumar
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2020; Springer Nature B.V
• Subjects: Abrasive finishing; Abrasives; Die steels; Dies; Engineering; Experimentation; Ferromagnetic materials; Finishing; Injection molding; Magnetorheological fluids; Mechanical Engineering; Permanent magnets; Permanent molds; Process parameters; Rapid prototyping; Reciprocation; Response surface methodology; Surface finish; Surface finishing; Surface roughness; Technical Paper; Tool steels; Workpieces; Blind hole; Nano-finishing; Magnetorheological (MR) fluids; Permanent magnets; Cylindrical; Magnetic field; P20 tool steel
• ISSN: 1678-5878; 1806-3691
• DOI: 10.1007/s40430-020-2225-6

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.