Experimental study of electrophoretically assisted micro-ultrasonic machining

In micro-ultrasonic machining (MUSM), a major part of the material is removed by the impact of abrasive particles. In the early stage of machining, abrasive particles are distributed uniformly in the machining area. However, as the process goes on, abrasive particles will be driven out of the machining area owing to the ultrasonic vibration of the micro-tool or work-piece and the rotation of the micro-tool in the fluid. As a result, the machining precision and machining efficiency will be reduced. In this paper, we propose a new method called electrophoretically assisted micro-ultrasonic machining (EPAMUSM) in which an electric field is used to prevent the abrasive particles from being driven out of the machining area. Experiments on EPAMUSM are conducted using a self-developed micro-USM system with micro-tool vibration, in which the control system of the micro-USM machine tool controls the machining force in a constant range. First, experiments comparing micro-ultrasonic machining with and without electrophoretic assistance are conducted. It is found that, with the appropriate processing parameters, EPAMUSM can improve machining accuracy and machining efficiency. Then, experiments with an orthogonal design are performed to reveal the main effects of the process parameters (abrasive particle size, spindle speed, DC voltage, force, ultrasonic power, mass fraction, and feed rate) on the material removal rate, and the optimal processing parameters are derived from the results.