Closer to Useful RFID

By Phil Burgert

Established factory-data-tracking technologies won’t lose their roles in manufacturing, but declining costs, faster read rates, better chip capacities and higher data-handling capacities are increasing the role of radio frequency identification (RFID).

“Bar codes are not going away, at least not in the near future,” says Helge Hornis, manager of intelligent systems for Pepperl+Fuchs. “Long term, there are some things we are working on, but that is way too early to talk about.”

Currently bar codes and RFID are seen as complementary technologies but Hornis says work is being done that might further reduce the cost of RFID tags. “Where the industrially hardened tag once cost $50, good quality tags now cost $5,” he says.

Hornis says research projects now underway are aimed at cutting costs of RFID tags or similar devices to 2¢. “It is not going to happen today because today the biggest part of the cost is the housing,” he says. “It’s not even what is in [the box] anymore.”

Bar code-based systems, notes Hornis, are inherently less rugged than RFID. “With an optical system you have a glass lens,” he says. “You could have moving parts and rotating mirrors.”

Sal Scafidi, strategic business manager for RFID at Omron Electronics, says one of the most important recent developments in RFID in manufacturing is increasing read rates and response times. “One of the last things you want to do is embrace technology that could slow down the performance of the machine,” says Scafidi. “It’s important that you select a reader that can handle the speed. You select a reader that is not dependent on the communication scheme with a PC, for example.”

Tom Kahn, Omron’s product marketing manager for automatic identification products and vision systems, notes the difference between a license-plate approach to RFID—with the tag serving as a pointer to externally resident data—or having all information resident on the tag involves questions of data security, network viability and uptime.

Kahn says the license-plate allows for traceability, pedigree or a warranty support, and he offers an example of tracking incoming material. “The incoming receiver would tie in the source of a material, the particular properties and the physical dimensions,” he says. “The license plate travels with the material and allows the system to configure or accommodate for the width, height, length and thickness automatically by interrogating the higher-level system.”

When there are warranty issues after production, a field technician can go back and determine the source for the raw material and assess what contributed to any possible problem, says Kahn.

Mark Sippel, product marketing manager for RFID at Balluff, says with manufacturing assembly and palletized systems his customers’ biggest current demand involves RFID range and flexibility. The fact that metal attenuates signal strength is the biggest hindrance to that demand. “They want more flexibility by getting greater range,” says Sippel. “To the naive user, this sounds easy but that’s one of the biggest RFID challenges.”

Sippel says Balluff and most of its competitors have been working on systems for the past two years that can provide ranges as far out as about 150 mm with tags mounted on metal. “As little as four years ago, you were lucky if you could get out past 30 mm,” he says. “In most cases you probably were limited to 20 mm or less.”

Part of the range extension is credited to more standardized RFID frequencies of 125 kHz and 13.56 MHz on the industrial side. That has helped, says Sippel, but he notes that especially in the 13.56 MHz range, some systems are even more susceptible to metal interference.

Mark DiSera, product marketing manager with Turck, says that two areas providing greater flexibility to machine builders are more innovative designs for transceivers and smaller package sizes for tags that allow direct metal mounting.

“Specifically, some manufacturers have started using standard proximity switch housings as transceiver housings,” says DiSera. He notes that machine builders have used proximity switches for many years, and until recently RFID transceivers have in some cases been too large or in a form that was not practical for many machine applications.

DiSera says that proximity switch-style housings have simplified RFID installations for machine builders, since these builders already are familiar with this type of packaging.