Radio frequency identification is creating big changes in the way companies handle product tracking, security, authentication, and more. Find out how the technology works and why screen-printing shops are in a great position to stake claims in RFID manufacturing.
By Wim Zoomer
As the demand for RFID systems increases, the need for fast, accurate, and consistent manufacturing methods also becomes more important. Whether it’s used for direct printing of the silver conductive antenna, printing the etch resist on the substrate, or printing the bridge and connection, rotary screen printing has proven to be a fast and effective technique for RFID production.
With rotary screen printing (Figure 3), a cylindrical screen transfers the desired antenna or mask image onto a moving web of material by continuously rotating the cylinder against the web at the same speed as the web is travelling. Inside the screen cylinder, a squeegee pushes ink outward and onto the substrate. Since the image is transferred without any deformation of the screen, the registration of the successive images is exceptionally accurate. Web widths on rotary screen presses used in RFID production typically range from 20-40 in. The systems also incorporate hot-air drying systems to dry the inks used in RFID manufacturing.
The cost-effective rotary-screen-printing technique is suitable for medium to large amounts of RFID antennas. Print speeds vary between 39-66 ft/min. The emulsion on a rotary screen can be strip-ped down to allow recoating and re-imaging the screen for another print job.
The productivity of rotary screen printing is high. Using a print speed of 50 ft/min on a web width of 20 in., the capacity of rotary screen printing is more than 600,000 credit-card-sized high-frequency antennas in one shift. Just printing one shift a day during one year, a shop could produce 120 million RFID antennas!
A promising technology
The use of RFID technology is expected to increase substantially between 2010 and 2015, and companies using the screen-printing process—whether it be high-speed rotary or conventional flatbed printing—are well positioned to capitalize on this growth. Thanks to screen printing’s accuracy, flexibility, and cost-effectiveness in applying conductive inks, masks, resistors, and other antenna components, the process has been instrumental in making RFID a practical reality and is certain to remain important in the future of RFID production.
Wim Zoomer is owner of Technical Language, Boxmeer, The Netherlands, a consulting and communication business focusing on screen printing and other printing processes. Zoomer has written numerous articles for screen-printing journals and is frequently called on to translate technical documents, manuals, and books between the English, French, Spanish, German, and Dutch languages. He is also the author of Printing Flat Glass. Visit his Website at www.technicallan guage.eu.
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