Current challenges in designing suitable inline quality control for formed metallic bipolar plates

The main objective of the KontiBIP [1] project is to develop a new production chain for the manufacturing of high precision metallic bipolar plates including new tooling and automation concepts suitable for large-scale production. Although forming bipolar half-plates from thin metal sheets (sheet thickness ≤ 0.10 mm) has the potential to increase the production capacity, the inline quality control remains a bottleneck in the production chain. Due to the complex structure of the formed bipolar plates, microcracks and necking, burr formation and layer defects can occur during production. The use of defective parts would thus be associated with high follow-up costs. For this reason, automated 100 % inline control is necessary, but it is associated with many challenges. So-called inline-capable multi-sensor inspection systems are often not available as standard solutions. In addition, the inspection concept must cover the entire surface in order to monitor multiple defect classes and inspection criteria in a contactless manner. However, the impact of the defect classes in the process are not well known and a standardized defect catalog is not available. Since the defects are usually in the micrometer range, optical systems reach their technical limits (resolution, data rate). Various approaches that take the different challenges into account will be discussed in detail. [1] The project "KontiBIP" - Hochratenfähige Herstellung metallischer Bipolarplatten mittels kontinuierlicher Fertigungs technologie" is supported by the German Federal Ministry for Digital and Transport (BMDV) on the basis of a decision by the German Bundestag.