2.5 MES: Comprehensive Traceability and Data Management

movement of the board must be mirrored by an electronic scan and status update in the MES.

2.5.2 WhatMandatory theTraceability Data (MES Records)

The electronic record must containbe (per serial)

Log these once per unitcomprehensive and updateauto-populated onby changes.machine Keepinterfaces itwhenever boringlypossible complete.to create a complete genealogy for each Serial Number (SN).

If your system can’t attach files, fix the system—not the discipline.

2.5.3 SimpleStatus Control and Routing

A simple status model (soensures routingautomatic isand automatic)correct routing, preventing boards from bypassing critical re-inspection gates.

Routing Rule: afterAfter a status of REWORK, the routeMES must includeautomatically insert the failing test station again(e.g., (andICT, anyFCT) downstreamback affected).into Nothe hopscotch.route. The board cannot proceed until that gate is successfully passed again.

2.5.4 Rework ticket:Ticket fieldsMandates

The endrework argumentsticket serves as the primary log for all repair activity and must be auto-generated upon the first failure scan.

• SNEssential /Fields: Log the SN, Refdes, /the Side
• controlled Defect codeCode, and Action Taken (controlled list), short free-text note if edge case
• Evidence: AOI/AXI images, scope traces, reflow plot snippet
• Action: what was doneswapped, (paste/flux,what temps,flux/temps nozzle,were part PN/lot replaced)used).
• Attempt Tracking: The ticket must explicitly track the attempt count (per refdes)component or site) and the number of heat cycles (if relevant (BGA/QFN limits)rework limits apply).
• Who/whenVerification: (operator/tech/QE)The ticket must list the required
• Verificationverification step(s) required(e.g., AXI check, FCT spot check) and link the digital proof (AXI,image/log) AOI,before ICT, FCT) + result linksclosure.

Close only when verification passes and status moves to PASS via the routed gates.

2.5.5 SerialGenealogy numbersand &Component labelsReplacement

When duplicates,a nocomponent ghosts)is replaced, the unit's permanent genealogy record must be updated instantly to maintain traceability down to the part level.

• OneNew Part Scan: The new part number and lot/date code must be scanned and linked to the board's SN =in onethe physical unit. Reuse never.MES.
• ReprintRemoved Part Log: = same data, same barcode,The reprintold reasonpart's loggedlot number; oldshould labelbe destroyed.flagged as removed, providing a complete record for any future supplier quality audit or field failure investigation.
• LabelSecurity correctionsItems:: voidIf unique identifiers (firmware hash, MAC addresses, encryption keys) are altered during rework, the wrong label in MES (status = VOIDnew values), applymust corrected,be attachlogged photo.and verified by the test system.

2.5.6 Final Packaging and Audit Controls

Final documentation ensures that the product shipped is the product verified, locking down the last steps of the process.

• Board↔boxBoard-to-Box mappingMapping:: The packer must scan all board SNs intoand link them to the boxfinal SN;Box SN. The system must block packpack-out if thethis map is missing.incomplete or if any board has an open ticket.
• MarkingTraveler after reworkBackup:: ifIn youthe addevent orof alteran DPM/label,MES logoutage, use new code in the SN record (Section 4.x practices).

2.5.6 Genealogy updates (parts you swap must leave footprints)

When you replace a component:

• Scan the new part PN + lot/date into the SN’s child list.
• If you remove a part, mark the old lot as removed (so supplier returns/SCARs find it).
• For security items (keys, unique IDs), record new values and invalidate old.

This makes supplier issues traceable without digging through benches.

2.5.7 Route after rework (the “must-pass” list)

Map defect → required verifications:

MES should insert these steps automatically when the ticket closes.

2.5.8 Paper traveler backup (when MES blinks)

• Pre-pre-printed barcoded travelers withas minimala fields:temporary, SN,physical WO,backup. ProductAll Rev,data statuscollected boxes,on signaturepaper lines.
• On recovery, back-enter: (timestamps, actions, photossignatures) (takenmust duringbe outage),back-entered theninto retirethe paperMES withimmediately aupon scan.system recovery.
• No paper-only workGuardrails: beyondThe aMES shift;must ifblock outage persists, declare controlled stop or bring up a light offline trackeractions that importscreate shadow data (e.g., automatically importing images from AOI/AXI directly to MES.
  

2.5.9manual Common scenarios (do this, not that)

A) BGA rework late in test

• Do: Move SNupload to REWORK,non-audited perform controlled rework (14.3), AXI, then rerun failed FCT steps (and any power rails)systems).
• Don’t: Wave it through because “it now boots.” AXI or it didn’t happen.

B)

Final Box opened for board swap (RMA)

• Do: Break board↔box map, set box HOLD, create child traveler for the board, repair & re-test, then rebuild the map and close RMA with notes.
• Don’t: Swap and scribble—mapping must match reality.

C) Label smudge at pack

• Do: Reprint with same SN; attach photo; VOID old in system.
• Don’t: Handwrite. Ever.

D) ECO mid-lot

• Do: Traveler shows ECN ID, split WIP into pre-/post-ECN lots; recipes and AOI programs rev’d; pack labels carry as-built rev.
• Don’t: Mix silently—this makes root cause investigations miserable.
  

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2.5.10 Roles & permissions (who can touch what)Checklist

Tight permissions prevent accidental “greenwashing.”

2.5.11 Guardrails against shadow data

• Block pack-out if any of: open ticket, missing AXI/AOI link for required rework, missing firmware hash, broken board↔box map.
• Auto-import images from AOI/AXI/test into the ticket (no manual upload to chat).
• Dashboard tile: “Units in REWORK > 24 h” and “Reprints today” (count & reasons).
• Weekly audit: pick 5 PASS units → verify images, genealogy, programming match labels.
  

2.5.12 Pocket checklists

At fail (operator)

• Scan to NG-QUAR; ticket auto-created
• Defect code picked; image/plot attached
• Unit parked in quarantine rack

At rework (tech)

• Claim ticket (REWORK); log action, temps/tools
• Scan new parts (lot/date); update attempt count
• Run required verifications; attach results

At close (QE/lead)

• All required gates re-passed (MES shows green chain)
• Status → PASS; comments “why fix worked” noted
• If label reprint: old VOIDed; photo saved

At pack

• Board SNs ↔ box SN mapped; firmware ID printed if required
• Traveler signed; CoC generated (if needed)
  

Conclusion: Maintaining complete, accurate traveler records and enforcing strict status control ensures that every board carries a verifiable history. This discipline protects traceability, prevents escapes, and transforms rework from isolated fixes into auditable improvements across the production line.