An efficient and effective methodology and simulation tools for die design and springback compensation for HSS and UHSS (Sprincom) : final report

HSS and UHSS offer high light-weighting potential for car body structural components. The large amount of springback after forming operations is currently limiting the market penetration of such steel grades, because of the large effort to be spent for tool design and tolerance satisfaction, requiring longer try out phases and increased development costs. The current research aimed at enlarging the use of UHSS in the automotive sector by developing and making available to material suppliers and automotive designers: • Deep knowledge about springback of UHSS; • Reliable and robust methods and tools for springback prediction and springback compensation by die shape modification, taking into account the effect of the steel property variability. An innovative methodology for die compensation has been successfully developed and tested based on the representation of both the die and sheet deformations in terms of particular sets of shape functions. The deep drawing tool is iteratively modified till an optimal configuration is reached, in which the final produced piece is as close as possible to the nominal one. The algorithm has proven successful in reducing springback on all the tested components of semi-industrial and industrial interest.