The present study investigates the manufacturing process of metallic bipolar plates made of SS316L with a thickness of 0.1 mm using rubber pad forming process. Two deformation types, convex or concave patterns, were used for producing channels in bipolar plates. The effect of concave and convex patterns on forming forces and slots filling will be created in this present study and then suitable condition for both patterns of deformation are achieved. For carrying out the experimental examination, two dies, convex and concave pattern within equal dimensions were designed and manufactured. In order to correct comparison of two die patterns, a rubber pad with hardness of Shore A 85 and thickness of 25 millimeters was used for forming of plates. A hydraulic press with capacity of 200 tons was used to make force on die. The concluded results signify that in an equal magnitude of force, die with convex pattern shows more depth of filling than concave die. By increasing magnitude forming force up to maximum limit, depth of filling in concave die will be constant and more increasing in magnitude of force will cause to destroy the rubber.