Knowing About FORMING

Automotive Manufacturing & Production, Oct, 2000

Here are some ideas and tools specifically tailored for those who have an applied interest in forming things with metal.

Taylan Altan, professor and director, Engineering Research Center for Net Shape Manufacturing (ERC/NSM), The Ohio State University, says that a uniform goal of automakers is to reduce the structural weight of vehicles while retaining the size of said vehicles...while adding all sorts of additional gear, like wiring and small motors for the explosion of audio/visual/tactile devices that are now common in cars. So, he suggests, there are two ways to accomplish this slimming.

One is to use light-weight materials, such as aluminum and magnesium. Altan suggests that the utilization of these materials is at higher levels in both Europe and Asia than in the U.S. He cites not only the well-known deployment by Audi of aluminum body panels and structural components for vehicles like the recently introduced A2 (which could probably be more elementarily named the Al 2), but he points out that BMW has long used aluminum for the 500 series rear axle.

While some people might point out that this approach of materials replacement is one that causes an increase in cost as aluminum and magnesium are both more expensive than the ferrous materials that are typically used for things like body and chassis components, the second approach to weight savings that Altan lists is one that is based more on intellectual capital than investment capital: design. He suggests that what some companies are doing is to achieve "stiffness through design."

For example, he points out that if you have a flat piece of material into which you put in a regular pattern of U-shaped bumps (think, in effect, the side view of a piece of corrugated cardboard with the corrugations being part of the bottom portion of the material and gaps where the material rises), that piece is much stiffer than a flat sheet of material. So by doing comparatively simple--and sometimes quite clever--design changes to parts, which may necessitate different types of forming processes, lightening can be realized with comparatively little investment required.

An increasingly common example of achieving stiffness through design, Altan says, is the implementation of tube hydroforming. This technology facilitates a variety of advantages beyond light-weight strength. Among them, Altan notes, are the facts that there is a reduced number of parts needed for assembly (as there is the ability to create complex configurations through the hydroforming process itself such that a single piece can have the topology that would otherwise require the assembly of discrete components), and that the assembly that is needed can be simpler than the traditional approach, especially from the standpoint of tooling requirements (i.e., reduced fixturing).

Altan knows more than a little something about these issues. For one thing, ERC/NSM, which he helped establish in 1986, has organized a consortium of 31 companies that is working on developments in tube hydroforming. And in addition to that process, there are four other metalforming areas that ERC/NSM lists among its core competencies: precision forging; stamping; high performance machining and die/mold manufacturing; education and training.

It is the last-named area that Altan maintains more needs to be done in the U.S. if advances in technology development and implementation are to occur at a rate similar to that in the parts of the world where there are competitive countries (although he does admit, "When U.S. companies decide to do something, they do it," which accounts for the extensive utilization of hydroforming in a comparatively short period of time). Altan suggest that because there is not as much training and education in manufacturing-related engineering in U.S. factories compared to what is the case elsewhere (e.g., he notes that there are plenty of people with PhDs running plants in northern Europe; he points out that the majority of graduate engineering students at places like Ohio State tend to be from other countries--and that many of them return to their home countries) there is a "hidden technology cost." In other words, what we don't know about manufacturing processes can cost us money in the long run.