Comparison of Milling and SEDM Manufacturing Processes for the Production of BPP-Forming Tools

Reducing CO₂ emissions from fossil fuels is a major challenge, and fuel cells offer an emission-free path to decarbonization. Their potential remains underused due to the high complexity of the system and manufacturing costs, particularly for the bipolar plate, which is a key component of fuel cells, due to its filigree channel structures. This paper focuses on the manufacture of BPP forming tools, which are used to create a precise flow field geometry using a stamping process. In this context a technology comparison of the manufacturing processes was made between die sinking EDM (SEDM) and milling for the production of forming tools. Using a full-format BPP analog geometry, dies and punches were manufactured using both manufacturing processes. Performance indicators such as machining time, costs, and the resulting quality of the forming tools were taken into account. Quality is assessed based on a combination of dimensional accuracy and surface quality. The results of this study provide the foundation for a technology comparison of the two manufacturing processes. Furthermore, subsequent forming tests will analyze the influences of the respective manufacturing processes on formed BPP half-plates. This paper provides guidelines on manufacturing BPP-forming tools regarding the manufacturing process and economic efficiency.