A New Approach for Applying a Non-conductive Mandrel in Electroforming of Complex Bellows-Shape

In this research, innovatively a flexible non-conductive polymer mandrel by applying graphite was used instead of conventional metal mandrels. To achieve a uniform shell thickness, a helical anode instead of usual flat anode and pulse reverse current instead of constant current were utilized. In this research, the effects of parameters such as current, pulse-forward time, pulse-reverse time on copper bellows-shape parts using pulse-reverse current in order to obtain proper thickness uniformity and hardness was investigated. To optimize the electroforming parameters, Response Surface Method (RSM) was applied. The optimum pulse-reverse and pulse-forward time for the set of parameters used in the experiments was determined to be I = 2A, T-F = 8 ms and T-R = 3.5 ms. Consequently, results showed that the type of current had a dominant effect on the uniformity of the copper bellows-shape parts on the non-conductive mandrel and the pules-reverse time played a significant role in obtaining efficient mechanical properties.