Hydroformed Structural Elements: An Economic Evaluation of the Technology

Hyrdroformed tubes have seen use in the aerospace industry for many years and are seeing increased use in the automotive body-in-white (BIW). The automotive industry has chosen to use hydroformings for a number of reasons including reduced part weight, piece count reduction, and the flexibility to form complex shapes of varying wall thickness. With all of these potential advantages, still one more provides the greatest incentive to switch from a stamped assembly to a hydroformed tube: the ability to reduce cost. It is generally accepted that hydroformings can indeed be cost effective to produce, yet the question remains: when should a stamped assembly be replaced by a hydroformed component?

This paper will attempt to answer the question above by laying out several case studies and comparing their direct manufacturing costs. By using a spreadsheet based costing methodology known as Technical Cost Modeling, it is possible to identify the parameters that drive direct manufacturing costs and discover how two processes compete as these parameters vary.