Click here to see our line card
Direct Parts Marking and Durable Tags
Bar code applications in chemical facilities often require a more durable substrate than paper or synthetic labels. Steve Skelton is president of Data ID Systems (Los Gatos, California), a company specializing in custom automated data capture system design. A significant portion of our efforts focuses on unique marking problems, he said. A new type of marking technology called zero contrast can often provide a solution. The scanning device works in three dimensions, where a sensor reads differences in height. The bar codes are embossed or punched out as grooves on a card substrate or created by cutting or milling slots on an object. Either concave or convex symbols can be read, at 5 mil, 10 mil, and 14 mil. The durability of zero-contrast codes offers tremendous advantages for harsh environments.
Mr. Skelton explained that the big advantage to this technology is that the bar code becomes as durable as the object itself. Three-dimensional bar codes can withstand spray paints and are chemical resistant. This same technology can be used on metal, rubber, Teflon, ceramics, or other durable tag materials to identify items that can't be direct-marked.
We've put this technology in a wafer manufacturing company, he said, where extreme cleanliness is the issue. Labels would emit particles of contamination. Direct marking by milling was the only solution. We reprogrammed the milling machine during final finishing so that marking cost only pennies more per item. If the customer is already doing any mechanical marking on the project, the cost of zero-contrast marking becomes negligible.
For information on this and other products, call 800-632-8243.
Bar Code Labeling and Marking In Hazardous Environments
Certainly chemical plants and distribution centers present bar code labeling challenges. Jud Minor spent 24 years in the chemical industry, and he's currently vice president of development for DATA2, a St Peters, Missouri, firm specializing in high-performance bar codes for harsh environments. The three critical elements in harsh-environment labeling, Mr. Miner said, are adhesive, media, and the top surface of the label. Selecting the proper adhesive to be used on surfaces that include metal, painted metal, molded plastic, and wool subjected to at lease five year of exposure is critical. These environments typically will be anywhere from -40degrees F up to 120 degrees F - all the way from International Falls (Minnesota) to Brownsville, Texas.
The proper face stock is equally important, he continued. Media have to withstand the same variations in temperature, as well as ultraviolet (UV) radiation and weather conditions - ranging from snow to rain to high humidity - that might include chemical contaminants. And finally, the copy also has to withstand UV, weathering, and a fair degree of abrasion resulting from typical abuse expected in a chemical processing environment, such as drums colliding with one another. Extreme environments may require an overlaminate because of painting used in industrial maintenance. On a Union Carbide project we were involved in, the answer to their problem was a 2-mil layer of Teflon laminate, so that paint used in maintenance operations could be removed by placing a piece of masking tape over the label and stripping it off.
As to printing technologies, Mr. Miner had this to say: If I were in a chemical plant, I'd want none other than industrial grade thermal transfer printers. Printers are exposed to abrasion, rough handling, particulate matter, and some volatiles. Thermal transfer printers are robust, durable, and compact, and the image - with resin or resin was film - has the ability to withstand a variety of elements.
However, in areas where flammable materials and explosion hazards are present, I'd want no printer. Preprinted labels would be a better choice. You simple don't bring printing equipment into those areas.
Mr. Miner and Thomas Kirkham (a consultant for the U.S. Department of Energy) provide seminars and consulting services on bar coding in harsh environments and hazardous materials labeling.
This article appeared on page 26 in the ID Systems June 1998 issue