APC Project (EHF)

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An Innovative and Promising Approach in Metal Forming Processes

The use of high strength steels and lower density materials (aluminum, magnesium) in automotive body and chassis structures is an excellent way to reduce vehicle weight. However, higher strength and/or lower density materials are inevitably accompanied by a decrease in formability: this leads to increased manufacturing complexity (cost) and a decrease in product design flexibility.

One of the most promising forming processes is electrohydraulic forming (EHF), which consists of discharging a high voltage current between two electrodes submerged in a fluid, and using the pressure wave in the fluid to form a sheet metal blank against a die at very high strain rates. Ford Research & Advanced Engineering has been developing the technology for EHF for a number of years and obtained several patents to protect the tool design. However, at the present time there is limited understanding as to why the formability of common automotive sheet materials increases so dramatically during this process.

Amino North America Corporation – a Tier 1 supplier to Ford is also the world-leader in sheet hydroforming of lightweight panels. Some preliminary collaboration between Ford and Amino has brought to light the possibility of combining both EHF and Amino’s state-of-the-art hydromechanical drawing technology into a hybrid forming process. Therefore, Ford and Amino have invited several organizations to collaborate in order to

(a) develop a better understanding of the mechanics and materials science of EHF,
(b) to develop numerical models to accurately simulate the EHF process,
(c) to conduct a series of laboratory- and industrial-scale prototype trials to determine the most effective process parameters for this hybrid process and
(d) to determine part and tool design guidelines that will fully take advantage of the increase in formability that this hybrid process offers.

Ultimately, this three-year project aims at advancing EHF science and technology so that it can be used for medium- to large-scale production of automotive parts in Canada.