The primary motivation that drives the popularity of tube hydroforming, particularly in the automotive structural industry is the anticipation and expectation of significant savings compared to established methods, like stamping and welding. These potential savings can be divided into 6 main categories. They are capital (facilities and equipment), tooling and part costs, as well as, weight reduction, assembly simplification and performance improvement. Careful and knowledgeable consideration of these factors with the goal of achieving the best balance should lead to choosing the most advantageous manufacturing option. Overemphasis on one factor may lead to disappointing results in some of the others.
This paper concentrates on the 1st 3 categories examining the impact of design decisions on overall cost. Due to the ‘newness’ of hydroforming, the possibility that design decisions made with partial knowledge may build in extra cost is higher. The latter 3 receive less attention, limited to how they relate to the cost categories.
Each of the 3 cost aspects will be broken down to show how cost is incurred and give more insight into minimizing it. The tradeoff between functional features and cost will also be examined to rationalize when increasing the latter is justified by improvement of the former. This paper should help demystify a relatively new technology and facilitate understanding the most economical way to make parts for a particular function.
The most knowledgeable initial decisions are essential because once a manufacturing path is chosen, changing direction is more difficult with each passing step.