Manufacturers of complex systems need to mark every part with an ID number, but etched or printed bar codes may not work because they are often covered by paint or special finishes. To address that problem, researchers at NASA's Marshall Space Flight Center have developed a magnetic-dot-based system with high-magnetic-coercivity ink, in which the dots are "written" in a matrix pattern. This writing can use a stencil or apply the ink in laser-engraved, etched, or machined recesses. A handheld reader senses the matrix pattern, similar to how a bar-code scanner works, and converts the pattern to a standard code-output pattern. The reader can sense the magnetic pattern through as much as 15 mils of paint—typically, five or six layers.
The system also has potential in nonaerospace applications, such as automotive production, in which manufacturers paint parts during production or parts become covered with grime and crud in the field, and security, in which vendors can deliberately cover and thus shield the code's existence from prying eyes.
NASA:
www.nasa.gov
