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Applications are growing for embedding RFID tags and other radio-frequency devices in plastic parts via insert injection molding. A presentation on “Challenges in Overmolding RFID Tags and Antennas” was one highlight of the recent Molding 2014 Conference in Newport Beach, Calif. It was presented by Lynn Momrow-Zielinski, co-owner with Joanne Moon of Extreme Molding LLC in Watervliet, N.Y. (See last July’s issue for a profile of their firm.)
Momrow-Zielinski is enthusiastic about this fast-evolving market, which accounted for 25% of her firm’s leads in the past year. She cited potential in GPS tracking devices for children and Alzheimer’s patients, personal fitness monitoring and feedback systems, tracking of medical supplies and wastes, safety sensors, credit-card-free payment systems, and wearable LEDs.
Key challenges in such applications, she said, were the temperature and pressure limitations of electronics and sensors, achieving suitable adhesion between the electronics and overmolding materials, and assembly challenges for high-volume production. Typically, these jobs involve overmolded subassemblies with multiple molded components of various materials, small sizes and complex geometries, and expensive, fragile electronics.
Momrow-Zielinski noted that the electronic components can cost up to $5 apiece, so low molding scrap rates (below 1%) are critical. She said that liquid silicone rubber (LSR, a specialty of her firm) is good for RFID tags because of the low molding pressures. However, the elevated cure temperatures of LSR are less compatible with embedded antennas.
TPUs and TPEs work better for those components, she said. (Momrow-Zielinski praised the assistance her firm has received from one TPE supplier, GLS Thermoplastic Elastomers, McHenry, Ill., part of PolyOne Corp.)
She said there are only a few molders active in this business today. For one job, the FiLIP wearable phone and smart locator for kids, several other molders refused the project before Extreme Molding took it on. For those who might want to get in on this action, she advises, “Be prepared for an R&D effort. It won’t go right the first time.”
Incidentally, the Molding 2015 Conference is slated for next June in Rosemont, Ill. That will be the first Molding Conference presented by Gardner Business Media (Cincinnati-based parent of Plastics Technology magazine) since acquiring the conference from its founder, Amos Golovoy, who will continue to organize it for the next three years.
For a small custom injection molder competing in today’s global market, Lynn Momrow-Zielinski has tw...