ASU Research E-Magazine: Freeform Fabs

Ampere Tseng is helping to develop a new production idea that would make Henry Ford proud. Work at his Freeform Fabrication Laboratory is not meant to replace the assembly line. But it is leading the way toward a process that allows for the quick production of parts or other products out of various materials.

Tseng is an engineering professor and co-director of ASU’s Manufacturing Institute. The process being developed in his lab uses no molds or tools. Items “print out” based on computer specifications.

With current technology, designers use a computer to create virtual models of engine blocks or other objects. The computerized model is then used as a pattern to manufacture a steel die. The die serves as a mold that is used to form the engine block. The die must be cast before the engine block is ready for use.

A company might spend more than $100,000 just to make the die. Such high initial investments are not cost effective when the end products are parts that might be worth only a few hundred dollars each.

Tseng’s vision allows designers to skip the expensive die fabrication stage. A designer would create the engine block using a machine similar to an inkjet printer.

An inkjet printer sprays out hundreds of tiny droplets of ink to make characters and words on a piece of paper. Tseng’s process would deposit tiny droplets of molten metal layer by layer to form the engine block.

The process already is being used with some success, but only for creating models with polymers and plastics, not for making useable metal parts. Current freeform fabrication machines use small strands of plastic. The strands are squeezed out and laid side by side to create a prototype. Typically, the result is not usable, except as a model.

Tseng and his colleagues are pioneering the use of aluminum heated to 1,000 degrees Celsius. The molten aluminum is then sprayed out into the proper form. If the process can be made to work with other metals or stronger materials, end products might be usable immediately.

“The process eliminates the tooling stage. When used to produce complicated products, it also eliminates the assembly process. You can produce very complicated parts directly,” Tseng says.

Tseng and other ASU engineers are working with industry to develop improved manufacturing processes. Their labs serve a dual purpose.

“We try to develop processes that have direct applications for industry,” he says. “We also try to demonstrate to students what the next generation of manufacturing processes might look like. We train our students to fit both today’s and tomorrow’s industry.”

Tseng says that practical applications for the free form process are endless. Because any design can be created in a computer, the specifications can be sent from any location to Tseng’s machine to produce a specific part. Students could design a product at one location, then send the specifications through the Internet and have it produced on the other side of town, or even in a different country.

A company with need for only a few parts could use the process to call up specifications and make those parts within a few hours. No storage space would be needed for dozens or hundreds of parts.

Visualize the need for spare parts on a future space station. A few machines could manufacture parts as needed. The need for expensive space shuttle delivery would be eliminated, which might take weeks or months.

“If you need mass production, this process cannot compete in the near future,” Tseng says. “But, it is good for small quantity applications.”—Gary Campbell