While the basic principles of hydroforming have been around for more than 30 years, application of the pressurized, water-filled, tube-in-a-die technique has found highly receptive markets only during the past few years. These new markets largely consist of producing various parts for cars and trucks.

Judging from the 2nd International Hydroforming Congress, sponsored by Schafer Hydroforming, (North American headquarters, Columbus, OH, German headquarters, Pluederhausen, near Stuttgart, a Schuler company), the topic of hydroforming automotive components will be getting even hotter in the next few years.

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One project that gave hydroforming a boost was the International Steel Consortium that produced the ultra-light steel auto body (ULSAB) body-in-white, a prototype of which was on display at the conference. Shown here is a sheet hydroformed prototype body panel.

So great is the interest in hydroforming that Schuler's president, Herbert Plocher, used the Congress as a forum to announce that his company is planning a technical center that will advise companies interested in investigating the technique. The scope of the facility is still in the planning stages. However, Plocher reported it probably will be located somewhere in the Detroit, MI, area, and will offer feasibility studies, design work and prototype production. (It could be open and operating as early as Spring of 1999, sources told MetalForming magazine.)

Automakers have been interested in reducing car weight for decades and hydroforming can mean upwards of 100 lbs. or more taken off each vehicle. Additionally, the pressurized water process greatly reduces the number of parts for each vehicle. So why not 10 years ago?

Sophisticated Controls

Why all the attention now? Professor Taylon Altan, director of Ohio State's Engineering Research Center for Net Shape Manufacturing, Columbus, OH, answered this question by pointing out that, "The hydroforming process has become an engineering and production success. Weight savings always have been of keen interest to automotive manufacturers. The technology of hydroforming, however, has not been capable of meeting production requirements until recently, largely because of a need for greatly improved controls. That's why hydroforming now is so attractive as a technical and engineering alternative."

In effect, the process now has been engineered up to production standards. This became evident as speaker after speaker discussed the latest hydroforming part producing systems in operation throughout the automotive industry.

The 2nd International Hydroforming Congress was held at the Opryland Hotel complex in Nashville, TN, and was linked to the Schuler plant in Pluederhausen, Germany, by satellite for a real-time hook-up with company officials. They provided conference attendees with a guided tour of the company's latest hydroforming press technology.

One project that gave hydroforming a boost was the International Steel Consortium that produced the ultra-light steel auto body (ULSAB) body-in-white, a prototype of which was on display at the conference. Coordinated by Porsche Engineering, the ULSAB prototype contains two major hydroformed parts--a tubular hydroformed side roof rail and a sheet hydroformed roof panel.

One of several identical prototypes was on hand for attendees to examine. As project leaders noted, the ULSAB body-in-white uses no new metallurgy and would save upwards of 100 lbs. in a standard sedan-sized vehicle. Besides hydroforming, the ULSAB prototype also uses tailor-welded blanks and steel/polymer sandwich material (See MetalForming, April 1998, pgs. 36-43 for in-depth coverage of the ULSAB body-in-white prototype).

Meanwhile, the number of hydroformed parts in all kinds of cars and trucks continues to grow rapidly. The advantages of using hydroforming over stamping or tube bending just cannot be ignored, noted Martin Steinmetz, sales director, Schuler SMG Engineering GmbH & Co., KG. These include the fact that "complex shapes can be formed using internal pressure and axial pull-in. Close tolerances can be kept." He also noted that technology and controls today allow all or at least many of the attendant operations used in the production of hydroformed parts to be integrated." In other words, the process lends itself readily to automation, and that means costs go way down.

Better Beetles?

As an example of how complex part shapes can be in hydroforming, Werner Meyer, project manager, hydroforming, Volkswagen AG, Braunschweig, Germany, discussed creation of the new Beetle rear-axle support frames by hydroforming. Objectives of the program that led them to consider hydroforming, he noted, were the standard list of attractions that so many car and truck makers have used to justify the switch to the pressurized water technique: "Reduction of weight, minimized fuel consumption, optimized safety, better quality, shortened production cycles and lower costs." Many of these attractions stem from the fact that fewer hydroformed parts are needed for any given frame, and that the process is very amenable to robotic welding and other types of automation.