QR codes for warehousing and logistics

Imagers are not phone cameras

A dedicated 2D imager has controlled illumination, a fixed focal range and a decoder tuned for damaged codes. It reads codes a phone cannot. If all your scanning is by hardware you control, you can print smaller than the consumer rules suggest — but test with the actual device.

If a courier or a customer might scan with a phone, use the phone rules.

Encode an id, not a URL

WH-4471-A beats https://warehouse.example.com/locations/aisle-4/bay-471/level-a. Shorter payload, lower version, bigger modules, better read rate on a scuffed label — and it works offline, which matters in a metal building.

Restricting the id to digits and uppercase puts the encoder into alphanumeric mode at 5.5 bits per character instead of 8, shrinking the code further for free.

Label specification

• Thermal transfer, not direct thermal, for anything living longer than a week. Direct thermal fades from heat and abrasion.
• Resin ribbon on polyester for freezer, chemical or outdoor use.
• Use the printer's native QR command (^BQ in ZPL) so modules land on exact dot boundaries.
• At 203 dpi, modules must be at least 0.5 mm. See labels.

Placement

Flat surfaces only, never across a box edge or seam, 10 mm clear of the label edge, and never under packing tape — a wrinkle in tape destroys local contrast.

Bulk generation

Generating thousands of location or asset codes is a bulk job. Decode-verify every one before printing a run — a systematic encoding error discovered after 5,000 labels is an expensive afternoon.