Experimental study of micro ultrasonic vibration machining

Ultrasonic machining (USM) removes very small amount of material and does not cause damage to the workpiece. USM has been downscaled to generate micro-scale features on nonconductive brittle and hard materials such as ceramics, silicon, and quartz glass. However, specific process mechanism related to material removal and tool wear is not well understood in micro ultrasonic machining (micro USM). This paper reports an experimental study of micro USM by drilling holes on silicon wafer. Ultrasonic vibration amplitude, abrasive particle size, and tool-workpiece static pressure are identified as main input parameters and drilling speed and tool wear ratio as output parameters. Relationships between the process inputs and outputs have been established based on the experimental data. It was found that abrasive particle size significantly determines the drilling speed and tool wear ratio. The complex interactions among three input parameters are also discussed. The reasons that tool rotation significantly improves the machining soeed are also briefly analyzed.