A multipass incremental sheet forming strategy of a car taillight bracket

Incremental sheet forming (ISF) satisfies the increasing demand for the production of small batch products or customized parts. Up to now, however, there are little studies or applications on the ISF process of geometrically complex products as a result of the long processing time and the difficulty in generating an appropriate tool path. In this study, an attempt was made to process a car taillight bracket which had several intricate geometrical characteristics, especially the nearly straight-wall region and the groove region. It was firstly verified that cracks and wrinkles are prone to be brought about in the two crucial regions of the target product if a traditional multipass forming was employed. Thus, a multipass strategy, based on a detailed area division which considered the processing depth, was approached. And this strategy required only one transitional model so as to shorten the manufacturing cycle. In this way, associated with each region was a corresponding tool path which can be easily modified. Based on the proposed multipass design, the taillight bracket was successfully processed without evident forming defects. And the thickness thinning rate approximately met the conventional requirement of less than 25 %. Then, as the transitional model plays an important role in the forming performance of the final product, the design of the addendum surface of the aforementioned two critical areas was discussed. It was verified that a regular transitional surface which is geometrically nearer to the final shape is able to obtain a satisfying forming quality.