Study On Equipment And Basic Process Of Micro-USM

Hard-brittle materials such as silicon, glass and ceramics are being extensively used in micro-mechanics because of their excellent physical, chemical and mechanical properties. At present the common high-precision methods of micro-fabrication include LIGA, electrical discharge machining(EDM), electrochemical machining(ECM), laser machining, ultrasonic machining(USM) and so on. It is necessary to study micro-USM technology because of it s advantages in machining hard and brittle materials over other methods.To machine micro features in hard and brittle materials, a micro ultrasonic machining (USM) is developed equipped with a wire electrical discharge grinding (WEDG) unit employed to prepare micro tools. The corresponding NC machining system used both in micro ultrasonic machining (USM) and electric discharge machining (EDM) is developed.The circular holes and square holes have been drilled in silicon for proving the system capability of equipment. A simple method is proposed for the amplitude measurement of ultrasonic vibration. The influence of some important machining parameters such as abrasive particle size, rotating speed and static force on the machining performance such as material removal rate, wear ratio are qualitatively studied through a series of experiments.Using the micro-tool fabricated by reverse copying method, micro hole array and cross shaped hole have been generated by micro-USM, and the difference of material removal rates (MRR) between micro hole array and single hole machining is experimentally analyzed.3D micro cavities have also been fabricated by applying Uniform Wear Method integrated with CAD/CAM software.In micro ultrasonic drilling, the gap of hole is unstable with different length of tool, and the radial vibration of micro-tool is considered as the dominate factor in this paper. The vibration model is established. To proving the theoretical model, the finite element analysis method is used to compare with experiment, and the theoretical results are basically in agreement with experimental results.