Rubber-Assisted Vaporizing Foil Actuator Forming of SS304 Bipolar Plates: Processes and Effects

Augmenting the channel depths of bipolar plates (BPPs) to improve their efficiency has been a key challenge associated with BPP forming processes. High-rate plastic forming is advantageous because it improves the forming limits of the metals and addresses the issue of BPPs tendency to experience fillet fracture.

A rubber-assisted vaporizing foil actuator forming (R-VFAF) process for BPPs is proposed in this paper. In this process, polyurethane rubber pads are used to improve the pressure distribution on the workpiece, and SS304 plates with channel depths of 0.6 mm were prepared with no obvious spring-back phenomena. A three-dimensional finite element simulation model was also established, and it was used to analyze the effects of the rubber pad on the velocity field. The results indicate that the R-VFAF process can be divided into four stages: upper round corner deformation, free bulging, contact bulging, and rubber rebounding. During the R-VFAF processes for SS304 polar plate, many fine strip-like deformation twin structures appeared inside the deformed grains, some of which stretched throughout entire grains. The use of a moderate amount of discharge energy along with a significant impact velocity is suitable for channel deformation. Also, thick rubber pads (>20 mm) are useful for producing desirable velocity distributions and uniform channel depths; however, they require large amounts of forming energy. A rubber pad with a low hardness value is a better choice for the R-VFAF process because it is useful for improving the impact energy utilization.