Rotary forming is a promising technique for high-volume, low-cost production of fuel cell components such as bipolar plates, but it needs to be better characterized for this application. In this paper, die design parameters in rotary forming of ultra-thin stainless steel 316 L sheets 100 μm thick are evaluated to explore how channels perpendicular and parallel to the rolling direction are affected by critical forming process parameters, namely depth of deformation, die corner radius, and friction coefficient. Channels are formed experimentally, and the results are used to verify the 2D and 3D simulations. The process is analysed in terms of die movement path and forming. Stress, strain, formed shape, and thickness are compared for the two main forming directions. Results showed that channels formed parallel to the rolling direction experience more plastic deformation and conform better to the prescribed geometry in terms of channel and flatness angles.