The Study On Parameter Optimization And Model Of Electric Discharge Machining (EDM) Micro-And-Small Holes

Micro electrical discharge machining (Micro EDM) has received much attention in the field of academic research and industrial application, which is attributed to its performances of high precision. However, efficiency and stability of Micro EDM has still been the choke point to apply in the industrial field. Electrical discharge machining micro-and-small holes is an important application domain of micro EDM. The optimization control of performances and process of micro-and-small holes has become the key techniques in micro EDM, where performance parameter optimization and technology model are urgently to be developed.In this paper, with the study of experiments, the effect factors on stability and efficiency and precision of EDM micro-and-small holes are investigated and analyzed. Then, performance parameter optimization and technology model are proposed. Firstly, the experiment with orthogonal array is designed, with choosing open-circuit voltage, peak current, pulse on time, pulse off time, servo voltage and electrode up-and-down time as the input parameters, and choosing machining rate, electrode consumption and holes clearance as the output parameters. In order to reduce the wave property of performance parameters, with the signal-to-noise ratio method in parameter settings, the experimental results of orthogonal array are analyzed, and the effect of the parameters on each performance objective are gained, which is prepared for the multiple objectives. Thereafter, though combining the effects results with the grey relation analysis, the optimizations with multiple performance objectives are transformed into the single objective optimization of grey relational grade, and the optimization combination with multiple performances is gained. The experimental results show that the proposed method based on signal-to-noise ratio and grey relation analysis is an effective method, which can raise the efficiency, precision and stability of micro EDM, simultaneously.Though choosing the experimental results as the learning sample, the performance predictive model of EDM micro-and-small holes is proposed, with the BP algorithm of artificial neural network. With choosing the performance parameters as the inputs, and choosing machining rate, electrode consumption and holes clearance as the output parameters, the proposed model is simulated. The comparative results show that the predicitive model based on BP algorithm coincides well with optimization combination with multiple performance objectives. Moreover, the proposed predictive model can predict well theexperimental observations of EMD micro-and-small holes, which provides the important theory bases for optimization control of machining process of EDM micro-and-small holes.