Gestamp successfully brings to market a weight-optimized B-pillar stamped from tailored blank using PAM-STAMP
We achieved very good results thanks to the accuracy of the simulation using ESI PAM-STAMP. We were able to use the springback prediction tool to evaluate the die compensation, despite the complexity of such a case with three different thicknesses and two weld lines.Eduardo Sulato and Fábio LichtenthälerEngenharia da Matriceria / Gestamp Automoción S.L.
Gestamp Automoción was entrusted with the design of a stamped automotive B-pillar defined with three different thicknesses. This was bound to bring a huge complexity to the stamping tool design in order to take into account the formability of each region of the tailored blank as well as the two weld lines.
Among the toolmakers consulted for this challenge in Brazil, Gestamp Paraná was nominated to develop this complex stamping process in Brazil, in spite of the additional difficulty linked to the three different thicknesses.
Transitions between different thicknesses must be seamless to reach required surface quality
Indeed, to add to the challenging geometry of the part itself, the complexity of the weld lines movement during forming needed to be considered as well. When the tool closes, the weld lines move constantly, and the tool geometry had to be adapted accordingly.
Due to the complexity of the simulation to be performed in ESI PAM-STAMP involving multiple thicknesses and weld lines Gestamp called upon ESI’s Brazilian support team to assist them in this task and to ensure that they would reach the best result in the shortest time.
Given the quality of the collaboration with the local ESI technical support team in Brazil, Gestamp extended the cooperation to include also springback calculation and die compensation using the explicit solver in ESI PAM-STAMP. To ensure good die compensation, Gestamp engineers made sure the strain distribution in the part was as smooth as possible. This was particularly difficult in a part with 3 different thicknesses.
Plastic strain analysis
Equivalent stress analysis – the influence of thickness is noticeable
Once the appropriate parameters were set, the springback was calculated with the tailored blank properties. The resulting tolerances were far from the required 0.7 mm.
The team then used ESI PAM-STAMP to compensate the tools and only a small region was still out of tolerance, located beyond the trim line. This was acceptable as it would be cut off the final part. The majority of the part was well inside the required tolerance.
After reaching such satisfactory results with the simulation, Gestamp successfully industrialized this particularly challenging B-pillar on the Brazilian market. Results achieved were of exceptional value as proven by the high precision observed in the actual formed part.
Springback before tool compensation
Springback after tool compensation
Gestamp Automoción is an international group dedicated to the design, development and manufacturing of metal components and structural systems for the automotive industry. Today, “Gestamp Automoción” is present in 22 countries and has 95 production centers (49 Plants in West Europe, 15 Plants in East Europe, 8 Plants in North America, 14 Plants in Asia, units in Brasil and in Argentina) and 13 R&D Centers, and over 25.000 people. The turnover in 2010 was 3,040 million Euros. Over the last decade, the company have experienced strong growth, thanks to the quality of their employees, who are dedicated to innovation.
For more information visit Gestamp