Investigation of a Surfactant-Enhanced Magnetorheological Fluid Damper for Enhanced Cutting Performance in Hard Boring Process

In machining, the boring process suffers from an increase in tool vibrations, surface roughness and cutting force due to the high slenderness ratio of the boring tool holder. A magnetorheological (MR) fluid damper was used in the boring process to enhance cutting performance during machining. However, the performance of the magnetorheological fluid damper is affected by the sedimentation of iron particles in magnetorheological fluid. In this study a magnetorheological (MR) fluid damper enhanced with oleic acid as a surfactant was used for enhancing cutting performance and reduce the sedimentation of iron particles in the boring process. The study also investigates the influence of oil grade, iron particle size, and surfactant concentration, using oleic acid, on the rheological and damping performance of the MR fluid. The presence of oleic acid as a surfactant in magnetorheological fluid significantly improved stability by reducing particle agglomeration and sedimentation, which ensured consistent rheological behaviour under magnetic field. The experimental results showed that the reduced tool vibration, improved surface finish and a decrease in cutting force was achieved when 7.5 wt% oleic acid with 5W-30 oil grade and 60 μm iron particles were used in the magnetorheological fluid damper. The study confirmed that the oleic acid effectively stabilized the magnetorheological fluid by minimizing particle sedimentation and ensuring consistent yield stress behaviour under cyclic magnetic activation.