The major question right now centers on where the technology is heading. If RFID can be achieved through the printing process, its costs of a finished transponder will come down dramatically, thus opening up more opportunities for RFID to be used. Another major question centers around whose technology will ultimately be used for RFID.
That is where XINK Laboratories Ltd. comes in. XINK, an Ottawa, Ontario-based specialist in conductive inks, has been doing some of the most creative research and commercialization, and has seen some of its products come to fruition during an exhibition on RFID antenna printing during Mark Andy’s RFID Focus seminar that showed its capabilities.
“We ran on a Mark Andy 2200 flexo press on 55 lb. semi-gloss stock, laying down a four-color process on top, printed a conductive ink Texas Instruments antenna on the backside, and then attached a strap to it with the Tamarack P500 machine creating the world’s first working printed RFID transponder fully assembled on a flexo press with an immediate read range of more than 14 feet,” said James Neilson, XINK’s product manager. “We can get that initial read range to increase out to 18 to 22 feet after 24 hours of drying. The process was developed in the lab and we've refined it to work on industrial sized presses. I think we surprised everyone, including other ink companies, in that our inks are cured ambiently, and we are getting calls every day.”
In addition, Creo, a division of Kodak, and XINK Laboratories presented a new class of secure flexographic RFID antenna printing inks at the PISEC 6th World Product & Image Security Convention held in Vienna, Austria.
Mr. Neilson said that XINK’s background in conductive inks for pharmaceutical smart packaging has been integral in its RFID research.
“We came out of the Information Mediary Corporation (IMC) Med-ic ECM project. We were founded to work with pharmaceutical packaging companies because people did not take their medications properly,” Mr. Neilson said. “By working with International Paper’s Shorewood Packaging, we created a conductive ink sensor grid that could detect when a patient pushes a tablet out of a blister pack of medications, and record the time that dose was taken at by attaching the sensor grid to a flexible printed circuit board embedded inside the pharmaceutical package.”
Screen ink has been thought of as a likely way to utilize conductive inks, but XINK found that flexo would be better.
“We could lay down conductive ink by screen, but that is too slow and screen inks are solvent-based,” Mr. Neilson said. “We decided to focus on flexo because of speed and a design limitation based on pharmaceutical bleached board substrates. We essentially had to lay down a grid of ‘paper wire,’ but couldn’t use heat to activate it due to the adhesive glue used in pharmaceutical packaging board. Over time, we perfected a way to make these conductive traces and when we improved the conductivity, we found we could make a highly effective UHF antenna.”
Cost is going to be a major driver for implementation of RFID on the unit level, and flexo could be the difference.
“To be really effective, you have to lower the cost of the entire RFID tag to less than a nickel,” Mr. Neilson said. “A chip should eventually get down to a penny or two, but copper antennas are acid etched, which is a slow, expensive process. We saw an opportunity to offer printed antennas in one pass using silver flexo ink and get a read range of 85 percent to 100 percent that of copper. We could print a thin film, two to four microns, a fraction of ink laid down by the screen printing process. It would be ambient cured at high speeds on flexo presses and can run at more than 250 feet per minute, and we’re not far away from 350 feet per minute.”
Mr. Neilson said XINK can customize its inks, and there are clearly markets developing already.
“We can tune our inks for specific applications and substrates, as we have our own press in-house,” he said. “We know firms who want to be able to be printing UHF RFID labels in less than six months, and we can work quickly to fine tune them on their presses.”