Electrorheological-Fluid-Assisted Ultrasonic Machining: Fundamentals, Mechanisms, and Applications in Micromachining

Ultrasonic machining is an effective non-conventional machining method for processing hard and brittle materials. In this process, an abrasive slurry is introduced into the machining gap to enhance material removal efficiency. The slurry is typically prepared by dispersing abrasive particles in a carrier liquid at a prescribed concentration. During machining, the ultrasonic vibration of the tool induces the movement of the abrasive particles within the tool–workpiece gap. However, the particles may be displaced away from the active machining zone, resulting in a reduction in the local abrasive-particle concentration and, consequently, a decrease in machining efficiency. To mitigate this limitation, particularly in micro-ultrasonic machining, electrophoretic assistance has been employed to control the movement of the abrasive particles. Under an applied electric field, the abrasive particles migrate in a controlled direction and become concentrated near the tool tip. This localized increase in abrasive-particle concentration can improve material removal efficiency, enhance the machined surface quality, and reduce edge chipping.