USC Team Builds Metal Chain Thin as 5 Hairs

A team of engineers at USC’s Information Sciences Institute has built what may be the world’s narrowest metal chain--as slim as about five human hairs. But the most remarkable thing about the chain is not its size, but the process used to build it.

Microelectrical mechanical devices, or MEMS, like the tiny chain are usually produced in so-called clean rooms. But the USC team has devised a less expensive way to make tiny devices.

The engineers built the chain by stacking ultra-thin layers of solid metal only a few thousandths of a millimeter thick--a technique inspired by an industrial process called rapid prototyping.

“You can make more complex designs by stacking layers than you can by machining or casting,” said Adam Cohen, a project leader at ISI in Marina del Rey.

Cohen and his colleagues also believe their electrochemical fabrication process--Efab for short--will allow for the production of cheaper devices, ranging from bar code scanners to coronary stents that keep arteries open.

“This is not like an assembly line, which manufactures products one at a time from individual parts,” Cohen said. “With Efab, tens or even hundreds of thousands of finished products can be made at the same time using a single process.”