Process Optimization of Ultrasonic Vibration-Assisted Electrical Discharge Machining for Brass Nozzles Based on Orthogonal Experiments and IPSO-BP Model

Abstract

Ultrasonic vibration assisted electrical discharge machining (EDM) is a novel precision machining method capable of further enhancing the efficiency and quality of EDM. Brass is frequently utilized as the material for precision agricultural spray nozzles due to its corrosion resistance and superior wear resistance compared to plastics. To obtain the optimal process parameters for ultrasonic vibration assisted EDM of brass, an orthogonal experiment scheme with five factors and four levels was designed. The material removal rate (MRR) and electrode wear rate (EWR) were selected as the primary evaluation indicators, while machining voltage, spindle speed, ultrasonic power, pulse frequency, and feed rate served as the main process parameters. Simultaneously, an improve particle swarm optimization (IPSO)-BP neural network model is train based on the results of the orthogonal experiments. By combining the aforementioned methods, the optimal process parameters for MRR were determined as follows: machining voltage of 95V, spindle speed of 2000 r/min, ultrasonic power of 45%, pulse frequency of 25 kHz, and electrode feed rate of 0.20 mm/s. The optimal process parameters for EWR were identified as: machining voltage of 65V, spindle speed of 3000 r/min, ultrasonic power of 75%, pulse frequency of 30 kHz, and feed rate of 0.16 mm/s. In the verification of above two sets of optimal parameters, the IPSO-BP model achieved R² accuracies of 87% and 94%, respectively. The overall prediction performance of the model is satisfactory, indicating that the model is capable of assisting and guiding the formulation of process plans for the subsequent ultrasonic vibration assisted EDM of brass nozzles.