02 June 2002
02 June 2002
A team of researchers is developing a robotic system to reduce the production cost of a lightweight, heat-resistant composite material, offering promise for future widespread applications.
The ""carbon-carbon composites"" are currently too costly to have many commercial uses in the everyday world. Because the material is able to withstand high temperatures without losing its strength, it is used primarily in disc brakes for commercial airliners, military jets and race cars.
""It is not presently possible to get this material into more consumer-related products like cars and trucks,"" said Thomas Siegmund, an assistant professor of mechanical engineering at Purdue University.
But a research team lead by Purdue, Honeywell Aircraft Landing Systems in South Bend, Ind., and the National Composite Center in Kettering, Ohio, has demonstrated a new manufacturing approach to produce the material at lower cost.
If the researchers are successful, the composite material might become affordable enough for a wide range of new applications, including engine parts such as pistons, biomedical devices and electronic components, such as new types of electrical transformers, and circuit boards capable of withstanding high temperatures.
""We have shown that it is possible to use robotic manufacturing technology to develop a process that leads to a new way of producing these types of materials,"" Siegmund said. ""It's a very different manufacturing technology.""
The work also involves the University of Notre Dame and Indiana University's Kelley School of Business.
The system will be detailed in a research paper to be presented Wednesday (5/22) during the 30th North American Manufacturing Research Conference at Purdue. The conference, from Tuesday through Friday (5/21-24), is sponsored by the Society of Manufacturing Engineers and was organized by a committee of Purdue faculty headed by Yung C. Shin, a professor of mechanical engineering, and C. Richard Liu, a professor of industrial engineering.
The research team has used the robotic-manufacturing system to reduce the production time of making aircraft brake parts by one-third. Shaving a third from the production time means the parts could be manufactured at less expense.
Depending on market fluctuations, the composite material currently costs about $50 per pound. But the price must be reduced to about $10 per pound for the material to be practical for large-volume applications in the automotive industry, Siegmund said.
""We're not there yet, but we're getting there,"" said Siegmund, who is managing a two-year project to develop the manufacturing system, in which a precision industrial robot deposits carbon fibers under computer control.
The project reflects a profoundly different manufacturing approach that promises to bring superior materials to the marketplace: Instead of conventional methods, researchers are now developing techniques to design the material itself at the microscopic level as the part is being made.
""To make a material like this, one usually has two options,"" Siegmund said. ""Either you build a very expensive fabric the same way you make a sweater: weave or knit it. Or, you do just the opposite: just randomly throw your fibers into a vat.""
""Weaving is very expensive. Throwing fibers in randomly is relatively cheap, but you don't have much control over the material properties. We want to do something in between. Instead of throwing fibers in randomly, we want to precisely deposit the fibers in a controlled way using a robot.""
The system is able to rapidly change the size and orientation of carbon fibers from one section of a brake disc to another, resulting in a better part. The engineers have used the robotic system to manufacture a brake material that contains short carbon fibers on the surface and longer fibers below the surface.
""The short fibers possess potential for good friction performance, and the longer fibers have better strength characteristics,"" Siegmund said.
Because the transition from one orientation to the next ideally is not abrupt - but gradual - such materials are called ""graded materials,"" said Siegmund, who specializes in using computer simulations to analyze the properties of materials so they can be improved.
Computer simulations and mathematical models allow researchers to predict how to precisely control the robot and to predict the properties of the final product.
""It's somewhat similar to controlling a paint spray gun,"" Siegmund said. ""You need to figure out how to precisely control the robot's speed, its height relative to the plane where you are laying down the fibers, how wide an angle to spray, how many meters of fibers per second to feed through the system.""
Purdue is working with the National Composite Center to develop the robotic manufacturing method. The final system will be used at Honeywell Aircraft Landing Systems, a business unit of the Aerospace Division of Honeywell International Inc.
The research paper was written by Purdue mechanical engineers Siegmund, Raymond Cipra and James Liakus; William Strieder, a professor of chemical engineering at Notre Dame; Robert Jacobs, at the Kelley School of Business; Alan Fatz and Tobey Cordell, at the National Composite Center; and Charles Parker, Frank Dillon and Mark LaForest at Honeywell Aircraft Landing Systems. Other participants in the project from Purdue include Rodney Trice, an assistant professor, professors Keith Bowman and Alexander King, all of the School of Materials Engineering, as well as Thomas Farris and Chin-Teh Sun, both professors in the School of Aeronautics and Astronautics.
The National Composite Center is a non-profit organization that seeks to promote, develop, demonstrate and support the commercialization of composite materials and processing techniques. Honeywell is a $24 billion technology and manufacturing company that specializes in aerospace products and services, control technologies for buildings, automotive products, specialty chemicals, fibers, plastics and other materials.
The two-year research effort received $2 million from the Indiana 21st Century Research and Technology Fund, which was created in 1999 to stimulate the state economy by nurturing research that is likely to result in new high-skilled jobs.
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