RFID in Manufacturing

RFID in Manufacturing: WIP Tracking, Tool Crib, and Quality Control

Manufacturing floors generate enormous volumes of in-process inventory — sub-assemblies, raw materials, fixtures, and finished goods — all moving between workstations continuously. RFID transforms that invisible flow into real-time visibility, eliminating paper travelers, reducing mis-builds, and enabling granular quality traceability.

Work-in-Process (WIP) Tracking

Work-in-process tracking is the highest-ROI RFID application in most factories. A passive UHF tag is attached to each pallet, tote, or sub-assembly at the start of the production order. Fixed readers at each workstation gate record arrivals and departures automatically.

Typical WIP gate setup:

Key metrics enabled by WIP RFID: - Actual cycle time per workstation vs. standard - WIP queues by location in real time - First-pass yield correlated to specific reader/operator/shift - Traveler audit trail for ISO 9001 non-conformance reports

Tool Crib and Tooling Management

Cutting tools, fixtures, calibrated gauges, and jigs represent significant capital. Uncontrolled tool removal, loss, and expired calibration are common pain points. RFID enables automated check-out/check-in without manual scanning.

Recommended tag types for tooling:

Use the Tag Selector to filter tags by metal-surface suitability and coolant resistance ratings.

A kiosk-style RFID cabinet reader can track tool removal and return without operator action. The reader records the TID of every tool in the cabinet every few seconds and alerts maintenance when a tool is out beyond its allowed duration or its calibration due date has passed.

Quality Control and Traceability

Each tag's EPC links the physical item to its production record in the MES or ERP. Inspection results, machine parameters, and material lot numbers are written to that record at each step.

Traceability chain for a critical component:

1. Raw material lot tagged on receipt; lot number written to EPC.
2. Sub-assembly tagged at first operation; parent lot EPC stored in user memory or backend database.
3. Reader at in-process inspection gate triggers automatic pull of inspection checklist for the operator.
4. Final assembly gate verifies all required operations completed before allowing part to proceed.
5. Finished goods tagged and commissioned before shipment; EPC encoded per EPC Gen 2 TDS.

For automotive and aerospace suppliers, this audit trail satisfies IATF 16949 and AS9100 traceability requirements.

Integration with MES and ERP

RFID middleware — or an edge processing layer — sits between readers and the plant floor MES. Its responsibilities include:

• Deduplicating repeated reads of the same tag at the same gate
• Correlating EPC to production order in MES
• Writing events to EPCIS if supply-chain visibility is required
• Generating alerts for exceptions (wrong part, wrong sequence, unexpected location)

For large facilities, deploy LLRP-compliant readers so the middleware can manage all readers through a single protocol regardless of vendor.

Deployment Checklist

• [ ] Conduct a site survey to identify metal interference and RF dead zones
• [ ] Select on-metal tags for all metal surfaces; test read range before bulk ordering
• [ ] Place reader antennas at decision points, not just convenient locations
• [ ] Integrate with MES via RFID middleware — do not bypass to direct-to-ERP
• [ ] Encode EPCs using a serialisation scheme consistent with EPC TDS
• [ ] Train maintenance staff on tag failure modes (coolant ingress, mechanical damage)
• [ ] Define decommissioning procedure for retired fixtures

ROI and Business Case

Manufacturing RFID deployments typically deliver payback in 12–24 months. The main value drivers are:

Use the ROI Calculator with your current WIP levels, labour rates, and quality escape costs to build a site-specific business case.

See also: Warehouse RFID Deployment, RFID ERP Integration, RFID on Metal Surfaces.