Investigation of Turn Number of the Coil on Tube Forming Performance in Electromagnetic Pulse Forming

Abstract

Electromagnetic pulse forming (EMPF) is an environmentally friendly and high-speed forming method without pollution generating. As the key component for energy conversion, the coil has a significant influence on the forming performance. Consequently, this paper aims to study the effect of the turn number of the coil on the performance of the tube forming through the theoretical analysis model and experiments. Based on the connection among the electrical parameters of the coil, the current parameters of the discharge pulse, and electromagnetic force, a theoretical model is built to analyze the qualitative connection between the number of turns of the coil and the amount of forming. Then, the EMPF experiments with the same discharge energy of 3.4kJ are carried out to verify the established model through the established EMPF equipment. The experimental results are consistent with the theoretical analysis. The results show that the peak value of the current amplitude and rise time of the pulse decrease respectively with the increase of the number of turns of the coil because the increments of the number of turns lead to the rising coil inductance. But the forming amount of the tube increases first and then decreases. So there is an optimal value of the turn number for the coil to generate the maximum Lorentz force to deform the workpiece. Therefore, it is worthwhile to choose the proper number of coil turn to improve the effect of EMPF.