Study On Control Method And Parameter Optimization In Micro And Small Hole EDM

With the developing of modern precise and micro manufacture, super refined and high precise micro EDM is widely used in micro manufacturing, which is attributed to its particular technology advantage of non-contact and micro 3D machining. As an important application domain of micro EDM, micro and small hole EDM is the representative of the research and development level of EDM. In the micro and small hole EDM with complex influence fators and strong randomicity, mature and credible machining system, accurate discharge states detection technology, right machining control method and technical parameter optimization are the key technologies of obtaining perfect and stable discharge states and implementing micro and small hole EDM with high efficiency, stability and precision. Therefore, the study in the technical difficulties above has significant academic meaning and application value.According to the characteristic and requirement of micro and small hole EDM, a micro and small hole EDM system with the rotation-libration machining organ and function consummate NC system is developed, which exhibits high precision and fast dynamic response speed. According to the complex discharge states in micro and small hole EDM, a successive mapping detection technology of micro EDM discharge states is provided. Using the discharge states as the inputs, a micro and small hole EDM control system is designed, and a micro and small hole EDM control method based on fuzzy logic algorithm is proposed. According to the optimization of machining time, electrode wear and hole clearance, the effects of the parameters on each single performance objective are gained by orthogonal experiment analysis based on the detection and control method above, and each single objective was optimized as well. Thereafter, importing grey relational theory, the the optimizations of multiple performance objectives are transformed into the single objective maximum of grey relational grade, and the optimization combination of multiple objectives is gained.The machining control method experiment based on the micro and small hole EDM system developed in this papershows that, with comparing the detection echnology and control method proposed in this paper to the traditional control method, machining efficiency is greatly improved. Moreover, the higher the depth-to-diameter ratio of the micro hole is, the more obviously the machining efficiency is improved. So the successive mapping detection technology of micro EDM discharge states and the micro and small hole EDM control method based on fuzzy logic algorithm are very suitable for the application in micro and small hole EDM domain. The experimental result of parameter optimizations of multiple objectives indicates that the grey relational grade method based on orthogonal experiment can optimize machining time, electrode wear and hole clearance simultaneously, and raises the efficiency, precision and stability of micro and small hole EDM.