Parametric optimization of a newly developed magnetorheological honing process for internal finishing of EN-31 cylindrical workpieces

The magnetorheological honing process is developed to meet the industrial needs of the inner surface nano-finishing of cylindrical components with different diameters. The process utilizes the magnetorheological honing tool which constitutes four radial polarized curved permanent magnet strips. The outer surface of the MR honing tool i.e. curved permanent magnet strips has the flexibility to move radially inwards or outwards according to the requirement of the diameter of the cylindrical inner surface to be finished. In the present paper, the response surface methodology is utilized to plan and evaluate the effects of various process variables on percentage change in surface roughness (Ra) value for the finishing of EN-31 cylindrical workpieces. The EN-31 material has its extensive applications in industry for manufacturing cylindrical dies and moulds for various cylindrical plastic products. The experimental analysis concluded that the percentage change in Ra value is mostly contributed by the working gap succeeded by the MR honing tool rotational speed, the percentage concentration of SiC particles, the MR honing tool reciprocation speed and the percentage concentration of carbonyl iron particles. With the identified optimum process parameters, experimentations have been performed and least Ra value of 95 nm is obtained from the initial value of 476 nm in finishing time of 120 min. Further to observe the finishing performed by the process over the surface, the scanning electron microscopy (SEM) test is performed.