Evaluation and optimization of effective parameters in electrohydraulic forming process

Abstract

Electrohydraulic forming (EHF) method is used extensively in industrial applications for its high capacity in improving the formability of various sheet metals. EHF is a high-velocity sheet metal forming process in which two electrodes are positioned in a water-filled chamber and a high-voltage discharge between the electrodes generates a high pressure to form the sheet metal. The EHF method contains innate complexity and depends on different parameters. Then, it is essential to investigate the process thoroughly and present the experiment procedure in such a way that an optimum condition can be met. In the present study, the effective parameters of the EHF (with and without using bridge wire) on free forming of circular Brass 260 sheets are analyzed by employing the design of experiment technique. Numerous experimental tests are performed, and the process parameters are optimized implementing response surface methodology and Minitab software. The most affective parameters were determined by analysis of variance method. Based on the results for EHF without using wire, it can be stated that maximum dome height is obtained when discharge energy is maximum and other two factors (stand-off distance and electrode diameter) are minimum. There also exists an optimum amount of electrode gap determined according to the process conditions. In case of EHF using wire, it was found that the aluminum wire was more efficient than copper and tungsten. Also, there are optimum values for the length and diameter of bridge wire that depended on the experimental conditions.