Investigation of Optimized Parameters for Magnetorheological Finishing the Internal Surface of the Cast-Iron Cylindrical Molds

The cylindrical mold is an essential part used in industries for the manufacturing of various cylindrical products such as beverages canes, domestics appliances, glass beakers, and polyvinyl chloride pipes. These products require features in its surfaces such as defect-free surfaces with high-quality, stable dimensions, the high extent of cylindricity, and functional transparency in glass material products. To acquire such features in the cylindrical products, the rotary magnetorheological honing (R-MRH) process is developed. In this work, the response surface methodology technique is employed for optimizing the process parameters for internal surface finishing of the cast-iron (CI) cylindrical workpieces. With the optimized process parameters, the experiments are performed to find out the effectiveness of the present finishing process for CI cylindrical molds. On the final MR-finished surface after 40 min of finishing, the roughness parameters (Ra, Rz, and Rq) get reduced to 0.05 µm, 0.4 µm, and 0.07 µm from the respective initial values of 0.420 µm, 2.4 µm, and 0.52 µm. The waviness parameters (Wa, Wz, and Wq) achieved on the final finished surface are 0.04 µm, 0.20 µm, and 0.06 µm from the initial values of 0.17 µm, 0.90 µm, and 0.22 µm, respectively. Also, the circularity (C) on the MR-finished cylindrical surface is improved to 0.0437 from the initial circularity value of 0.1207. The significant changes in Ra, Wa, and C values as well as visuals of scanning electron microscopy images reveal a better sense of functionality improvement of the cast-iron cylindrical molds.