Experimental and theoretical analyses of material removal in poppet valve magnetorheological finishing

Poppet valves used in internal combustion engines have a high risk of failure due to significant temperature and pressure. These poppet valves need surface finishing at the nano-scale level to prolong their life during their working use. In the present research, the chosen poppet valve has narrow ridge profiles, which is difficult to nano-finish by conventional processes due to certain limitations. The magnetorheological fluid-based finishing method can be effectively used for this kind of complicated narrow profile. For the magnetorheological fluid-based finishing processing of the poppet valve, a novel magnet fixture and setup is used. For checking the efficiency of this setup, surface characterization and surface roughness for polished and unpolished surfaces are outlined using a field-emission scanning electron microscope, microscope and optical profilometer. The final surface roughness of S_a = 23.1 nm at poppet profiles were obtained. All manufacturing defects like burrs, dents, scratches and pits are almost removed. The study of finishing forces in the magnetorheological fluid-based finishing method is also carried out using magnetostatic fluid–solid interaction, experimental and theoretical analysis. This force analysis supports the development of the material dislodgement model to anticipate material removal rate while finishing. The gap (error = 12.87%) between the experimental and theoretical material removal rate is marginal. It has high accuracy and reliability for specific applications.