Screen printing RFID antennas on PET: a roll-to-roll checklist

Rotary or flatbed screen?

Some antenna inks are made for one press type. Henkel describes LOCTITE ECI 1016 as a highly conductive, low-viscosity silver ink suitable for high-speed roll-to-roll rotary screen printing, particularly for antennas on PET, and lists a rotary mesh in its print parameters. Other conductive coatings target other processes: Henkel lists LOCTITE EDAG PD 056 for high-speed rotogravure printing, with smart labels/RFID among its applications. Flatbed roll-to-roll screen printers such as the LC-6080SYJ-C print with a flat screen and squeegee on an indexed web, so use an ink the supplier qualifies for flat screen printing and confirm viscosity and mesh with them.

Drying profile vs the oven you have

Henkel’s data sheet for ECI 1016 recommends a drying cycle of 2 minutes at 150 °C, with forced air or infrared, and notes that higher temperatures for longer exposure improve performance. It reports a sheet resistance of 0.0065 Ω/sq at 25 µm after 10 minutes at 150 °C, and a 5B cross-cut adhesion grade on untreated PET.

Compare that with the line: the LC-6080SYJ-C specification lists a dryer temperature from ambient to 120 °C over an approximately 60 m drying path. An ink that needs 150 °C would not reach its recommended profile in that dryer, so either choose an ink qualified at a lower temperature or specify a different drying configuration. Dwell time is drying length divided by average web speed; work it out for your target output.

Measure the conductor, not the look

• Measure sheet resistance (four-point probe) and trace resistance at the start, middle and end of the roll and across the web width.
• Record dry film thickness; sheet resistance is quoted at a stated thickness.
• Check adhesion on the actual PET after drying, and again after any lamination.
• Keep the ink lot, screen, squeegee and oven settings with every sample.

Registration for bonding

Antenna geometry and the pads where the chip or strap is bonded set the registration budget, especially when the antenna has a printed bridge over an insulating layer. CCD mark alignment on the LC-6080SYJ-C is specified with a repeat-registration range of ±0.03 mm; prove the result on your film, because film stretch and shrinkage in the dryer also move the print.

What to send for a trial

• Antenna drawing with critical dimensions and bonding pad positions
• PET grade, thickness and roll width
• Silver ink and its data sheet; any insulating or bridge layers
• Target resistance and output per shift

For multilayer printed circuits, also read printed silver, carbon and dielectric stacks.

Related LICHAO equipment

• LC-6080SYJ-C roll-to-roll CCD screen printing machine
• LC-FZSYJFG-6060 four-column CCD roll-to-roll screen printer