Modeling and simulation of material removal characteristics in magnetorheological shear thickening polishing

Magnetorheological shear thickening polishing (MRSTP) was experimentally demonstrated to achieve nano-level surface quality in previous studies. The aim of work is to further investigate numerical simulation and material removal characteristics during the MRSTP process. The apparatus of magnetic field generation was designed and developed. The model of magnetic field distribution was imported to computational fluid dynamics (CFD) module to generate desired polishing environment. Polishing stress behaviors were analyzed based on various polishing parameters through the CFD simulation results. It was found that the pressure on the workpiece surface decreased with the increase of the rotational speed of the workpiece while it increased with the increase of the flow velocity of the MRSTP media. A continuous increment in shear stress on the workpiece surface was observed with the increase of the rotation speed of the workpiece and the flow velocity of the MRSTP media. Based on the characteristics of polishing pressure, material removal rate (MRR) model of MRSTP process was established. A serial of MRSTP experiments were conducted on aluminum 6061. Surface roughness (Sa) of 79.0 nm was obtained, which was improved over 77%. The simulated model and MRR model were experimentally validated. The average error between theoretical and experimental results was 4.1%. It can provide a useful guidance for the novel MRSTP process.