By 1996, Marshall Space Flight Center researchers felt that many aspects of compressed symbology were ready for introduction into the commercial sector, even though the marking techniques developed to that point had not proven suitable for highly stressed NASA parts or could not provide the resolution needed for small parts. In August 1997, Marshall Technology Transfer formed an alliance with CiMatrix and its parent company, Robotic Vision Systems, Inc., (RVSI) to develop commercial applications for NASA's marking processes for the Data Matrix™, which is the CiMatrix patented version of the matrix symbol. The alliance also enabled development of new marking methods that would satisfy NASA's requirements on stress-critical hardware.
The applications for the Data Matrix™ seem unlimited. Readable symbols have been applied on more than 80 different materials, including metals, plastics, glass, paper, fabric, ceramics, and others. Application processes have been tailored to materials, and some materials can be marked by use of multiple techniques.
Matrix symbols can be applied to aluminum by dot-peening, electrochemical etching, laser marking, or laser bonding; or by ink-jet, silk-screen, stencil, or film deposition. The symbols can be embroidered on cloth or stenciled onto rubber. There is a technique for marking almost any substance or item. Regardless of the technique used, the mark is permanent, is smaller than a bar code, and can be easily read by use of a CCD video camera.
Before compressed symbology was available, manufacturers of computer chips had no way of marking their products, and counterfeit chips flooded the market. The same is true of other small electronic parts. Automobile manufacturers can use compressed symbology to track each piece of an automobile, thereby narrowing the scope of, and simplifying, the recall process. The symbols have already begun appearing on items used every day. Because of their versatility, data-matrix symbols are being used to mark a wide variety of products, including such household items as jars of mustard, deodorant sticks, vitamin jars, and packages of photographic film. Data Matrix™ has now become the symbol of choice for direct marking of parts in the automotive, electronics, and aircraft industries.
But it does not stop there because NASA has part-identification needs that go beyond visible marks. Identification marks might be covered by paint, cork, foam, or a number of other coatings designed to protect parts. Six techniques for reading identification symbols under coatings, through containers, and within an assembly are in the patent process. NASA has engaged partners to develop portable devices to implement these techniques.
Compressed symbology will have untold implications for industry as well as for NASA. New marking techniques within the ambit of compressed symbology, possibly ready this year, should open the door to marking stress-critical hardware.
The 15-year effort to develop these identification technologies has resulted in a NASA preferred standard and handbook. NASA Technical Standard 6002, "Applying Data Matrix Identification Symbols to Aerospace Parts" and NASA Technical Handbook, "Application of Data Matrix Identification Symbols to Aerospace Parts using Direct Part Marking Methods/Technologies" can be found at website http://standards.nasa.gov.
This work was performed by Fred Schramm of Marshall Space Flight Center; Donald L. Roxby of the CiMatrix Symbology Research Center (formerly of Rockwell); Willis L. Pavolini, Terry L. Higdon, and James D. Teed of Rockwell/Boeing; and Ward F. Davis and Robert Sant'anselmo of Veritec.
Refer to MFS-28960/61/28776/867/ 974/959/31015 volume and number of this NASA Tech Briefs issue; and the page number.