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New Mexico State professor studies way to improve advanced manufacturing process

A New Mexico State University professor is using computer simulation to improve the efficiency of an advanced manufacturing process.



Yuwen Zhang, an assistant professor of mechanical engineering at New Mexico State University, has earned a Young Investigator Award from the U. S. Office of Naval Research for his research on computer simulation of an advanced manufacturing process. (NMSU photo by Darren Phillips)

hang, an assistant professor of mechanical engineering, has earned a $300,000 Young Investigator Award from the U.S. Office of Naval Research for his research in fundamental models of selective laser sintering of metal powders, an advanced manufacturing process.


Selective laser sintering is an emerging manufacturing technology in which three dimensional machine parts can be built from computer aided design (CAD) data, using polycarbonate, nylon or metal powders that are placed in molds and formed in layers using moving laser beams, Zhang said.

In traditional manufacturing, a part is first cast, then has excess metal ground or filed away. The process requires time and precision machining. Selective laser sintering has the potential to be much faster, and could allow rapid prototyping of parts in the design phase, Zhang said.

But the process is in the early stages of development and still has some problems, he added.

"At this time there are some SLS machines available in the market. However, they are mainly for polycarbonate powders. With metal powders, it is difficult to obtain parts from the loose powder that are non-porous throughout their structure, because the sintering mechanism for metal is different from that of polycarbonate powders," he said.

Heat transfer is an important issue in the process. If heat is not distributed properly through the metal powders held in the machine, the sintering can occur in some unwanted areas, or "voids" -- porous areas -- can exist in the part's structure, Zhang explained.

Currently trial and error is the only way to find the proper parameters for making parts using a particular material. Zhang's research aims at using computer models to simulate the process beforehand.

"What I'm trying to do is predict temperature distribution in the powder bed of a sintering machine, so that we only sinter the part needed and keep the rest of the metal loose powder," he explained.

The Young Investigator Awards are made each year to support basic research by faculty at U.S. universities whose work shows exceptional promise. The researchers are selected on the basis of professional achievement, research proposals and support from their universities. Zhang is one of 26 researchers nationwide, and the only researcher in New Mexico, who received the award this year.

The award carries with it a $300,000, three-year grant.

"I'm happy to have received the award. With its support, I will be able to employ two graduate students and, perhaps, some undergraduate students to help me," Zhang said.

Zhang received his Ph.D. degree in mechanical engineering from the University of Connecticut in 1998. He was a senior engineer with Thermoflow Inc. in Sudbury, Mass., before joining New Mexico State in 2001.

Photo is available at http://ucommphoto.nmsu.edu/newsphoto/zhang_yuwen.jpg.
CUTLINE: Yuwen Zhang, an assistant professor of mechanical engineering at New Mexico State University, has earned a Young Investigator Award from the U. S. Office of Naval Research for his research on computer simulation of an advanced manufacturing process. (NMSU photo by Darren Phillips)

Jack King
March 25, 2002