Offshore manufacturing has a dark side when it comes to injection-molded parts. Unreliable molders can make illicit materials substitutions in order to save a few bucks or to work around supply problems. And the really unscrupulous molders can engage in outright counterfeiting. RTP Company (www.rtpcompany.com) has started to combat both problems by embedding a "secret code" into some of its plastics.
Working with technology from MicroTrace LLC (www.microtaggant.com), RTP can now add traceable "microtags" particles to any of its thermoplastic compounds. Each of these particles contains microscopic layers of color whose sequence corresponds to a unique numeric code. "A specific sequence is produced for each customer or application," explains RTP Color Manager Stu Swain, adding that MicroTrace registers the codes in a database and uses each one only once. MicroTrace claims it can derive more than 37 million unique codes from its technology.
Particle size for the microtags varies between 20 and 600 microns, depending on the application, base material, and the need to be visible to the naked eye. In most plastic applications, the particles range from 75 to 150 microns and are easily spotted under ultraviolet light with a 100X magnifying glass, Swain says.
MicroTrace makes particles from what Swain calls an "inert thermoset plastic," and a few of them go a long way. The amount of microtag particles in a finished part would vary with wall thickness, size, and color of the base resin. But as a rule of thumb, RTP recommends about 1,000 microtags per part. A gram of the microtagging material, meanwhile, contains about 500,000 particles. This super-low letdown ratio bodes well for both the cost and performance of microtagging. "You use so little of the material that it doesn't add much cost," Swain says. In a few cost-sensitive applications, he has seen customers get by with fewer than 1,000 particles per part. "They just have to spend more time looking for the particles later, " he says.
As for mechanical performance, Swain reports that microtagging technology hasn't triggered any noticible loss of mechanical or physical properties. "It certainly has less of an influence than adding conventional color to the resin," he says.
RTP has applied microtagging to a wide variety of thermoplastics, including those its engineers considered to be acid tests for durability. "It survives in the worst kind of molding conditions," Swain says. For example, the company has successfully added microtags to black PEEK, which molds at 700F. "You can still make-out the microtags in the finished part," he says.
Though first developed for the explosives industry and used in security products for nearly 20 years, microtagged thermoplastics have recently found applications in counterfeit-plagued markets such as sporting goods, entertainment, and electronics. Not surprisingly, RTP's customers haven't been willing to disclose their use of microtags. But the technology's most popular use so far, at least among RTP customers, has been keeping tabs on distant molders who might be tempted to cheat. Other customers have looked at the technology as a way to clamp down on counterfeiting done by their own molders using their own molds. "It's good for those cases where 100,000 parts go out the front door and 200,000 go out the back," says Swain.