Behind every RFID label that gets applied to a pallet, a garment, or a pharmaceutical carton is a production process that combines precision printing, electronic encoding, and quality verification at speeds that can exceed thousands of tags per hour. Understanding how that process works matters whether you are specifying a label production line, evaluating a supplier’s capabilities, or trying to diagnose why a proportion of your tags are arriving unreadable.

From Inlay to Finished Label

The starting point is the inlay: the raw RFID component consisting of a chip bonded to an antenna on a substrate. Inlays are manufactured by chip and inlay producers — companies like Impinj, NXP, Alien Technology, and EM Microelectronic on the chip side, and a wider range of inlay converters who take bare chips and assemble them onto antenna substrates at scale.

The inlay arrives at a label converter on a reel, typically supplied as a wet inlay (without adhesive) or dry inlay (with adhesive already applied). The converter’s job is to turn that reel of inlays into finished labels ready for application. That process involves laminating the inlay between a face material — paper or synthetic — and a liner with an adhesive layer, then printing whatever graphics, barcodes, or text the customer requires on the face, and encoding the chip with the correct EPC or other data.

How Encoding Works

Encoding is the process of writing data to the tag’s EPC memory bank (and potentially other banks) during the production run. It happens using a read/write antenna integrated into the converting or printing line, positioned precisely over the tag as it passes through. The encoder communicates with the chip using the standard EPC Gen2 air interface protocol, writes the specified EPC, verifies the write by reading back and comparing, and marks any tags that fail verification.

The EPC written to each tag must be unique if the deployment requires item-level serialisation. In practice this means the encoding system maintains a sequential or randomised counter, formats each value into the correct EPC encoding scheme (SGTIN-96, GIAI, or a custom format), and writes a different value to each successive tag. Keeping track of which EPC was written to which physical label, and tying that back to a commissioning database, is part of the data management challenge in high-volume production.

Write speed is a constraint. UHF chips can typically be written and verified in a few milliseconds, but the line speed of the converting equipment must be matched to the encoding station’s throughput. Running the line too fast relative to the encoder’s cycle time results in missed writes and failed tags. Most production lines include a speed governor that balances throughput against encoding reliability.

Print and Apply Systems

Not all RFID labels are pre-printed. In distribution centres, manufacturing facilities, and retail back-of-house operations, print-and-apply systems produce RFID labels on demand and apply them to products or packaging in the same automated step. These systems combine a thermal transfer or direct thermal printer with an integrated UHF encoder and a mechanical applicator that places the label in the correct position on the passing item.

Zebra, SATO, Honeywell, and Printronix are among the main suppliers of RFID-capable industrial printers. The printer firmware handles encoding as part of the print job: the label template specifies what data goes in the EPC field, and the printer writes it during the print cycle before the label is dispensed. Labels that fail the internal verification check are voided — printed with a void pattern or wound past the applicator — and a replacement is produced automatically.

Print-and-apply systems are common in warehouse environments where labels need to include variable data such as order numbers, batch codes, or destination addresses alongside the RFID capability. The flexibility to print on demand rather than using pre-printed label stock is operationally valuable, at the cost of higher per-label unit cost and the overhead of managing printer hardware and consumables on the production floor.

Quality and Void Management

No production run of RFID labels achieves 100 percent yield. Chip attachment failures, antenna defects, encoding errors, and verification failures all contribute to a void rate that varies by inlay type, production speed, and equipment quality. Industry benchmarks for good-quality UHF inlay production typically target void rates below one percent, and the best production lines achieve significantly lower than that, but any specification or purchasing decision should account for the fact that some percentage of a reel will be unusable.

Void management matters because dead tags in a reel create gaps in the label sequence. If a commissioning system expects consecutive EPCs and a void tag creates a gap, the downstream database needs to handle that gracefully. Most production systems handle this by skipping the void position and continuing with the next sequential EPC, logging the skipped value for reconciliation.

For high-security or regulated applications, every tag’s EPC and TID should be logged at the point of production, creating a complete manifest of what was produced. This manifest becomes the reference for commissioning: when a tag is read in the field, its EPC can be cross-referenced against the production manifest to confirm it is a genuine tag from an authorised production run rather than a copy.

Serialisation at Scale

The operational challenge of encoding tens of millions of tags per year with unique EPCs is primarily a data management problem rather than a hardware problem. The encoding hardware can handle the throughput. What requires careful design is the system that generates EPC values, distributes them to production lines across potentially multiple facilities or contract manufacturers, ensures no duplicates are ever produced, and reconciles the produced quantities against the commissioned database.

GS1 provides a framework for EPC namespace management that addresses this at the enterprise level, allocating company prefixes and defining the encoding schemes that partition the EPC number space. Organisations running high-volume RFID programmes typically integrate their EPC generation with their ERP or supply chain management system, so that tag production is triggered by and linked to specific product orders rather than running independently of business processes.

Getting the printing and encoding infrastructure right is unglamorous work compared to the visible technology on the reader and software side, but it is where data quality either gets established or gets undermined. A tag that leaves the production line with the wrong EPC, an unverified write, or a marginal chip that will fail in the field is a problem that no amount of reader infrastructure or middleware sophistication can fix downstream.

This article first appeared on RFID News (rfidnews.co.uk), the independent news site for RFID and NFC. Republication and AI use are welcome with RFID News credited as the source and a link to the original.