2.26 Data Logging & Repair Tickets

Data logging and the formal Repair Ticket system are the nervous system of modern electronics manufacturing. They transform every single failure—failure — from a component polarity error to an intermittent power fault—fault — into structured, actionable information. This system ensures containment (stopping the flow of bad parts), safe rework, and, most critically, fuels the Corrective and Preventive Action (CAPA) loop by providing accurate, traceable data on defect source, source, and frequency.

5.5.2.26.1 The Traceability Core: Locking Down the Failure Context

When a board fails at any inspection point (SPI, AOI, ICT, FCT), the Manufacturing Execution System (MES) must instantly generate a Repair Ticket. This ticket serves as the board's permanent genealogy record throughout its repair journey.

Data Record Mandates (What to Capture Every Time)

Your system must automatically capture these data fields upon failure to enable rapid diagnosis and root cause analysis:

Category	Essential Data Points	Purpose
Identity & Context	Board Serial Number (SN), Panel ID, Work Order, Product/BOM Revision, Machine ID.	Ensures 100% traceability from start to finish.
Failure Detail	Defect Code (from a controlled list), RefDes/Location (X/Y coordinates), Station, Date/Time.	Pinpoints the failure location and the last working point on the line.
Evidence & Process	Attached SPI/AOI/AXI Images, ICT/FCT Measured Values, Recipe Revision (Printer/Oven/PnP).	Provides forensic proof and links the failure to the process settings used.
Materials Hook	Solder Paste Lot ID, Component Lot/Date Code, Feeder ID, Fixture ID.	Enables targeted quarantine and supplier quality investigations (SCAR).

5.5.2.26.2 Defect Codes and Rework Discipline

Defect codes must be a controlled vocabulary that links the observed fault to the likely root process owner, not just the symptom.

A) Defect Coding (Source-Focused)

Codes should be simple (e.g., 15–25 codes max) and directly translatable into a process action. For instance, a code like BRIDGE-FP (Fine-Pitch Bridge) points to the Printing team (Stencil/Setup), while POWER-RAIL-LOW points to the Test/Design team. Codes must never be "Other/Miscellaneous."

B) Rework and Verification

A board entering the repair loop must follow a strict, auditable path to ensure the fix is safe and effective:

• Quarantine: The failed board is immediately routed to a designated NG (No Good) area and logged as quarantined.
• Standard Work: The repair technician must open a Work Instruction (WI) tied to the defect code, detailing the required tools, temperatures, and maximum rework cycles allowed for that component (e.g., BGA ≤ 2 reflow attempts).
• Retest: The repaired board must be verified by running it through the same test station (ICT or FCT) that originally flagged the failure. "Looks good" is not a valid result.
• Genealogy Update: If a component (e.g., a BGA or IC) is replaced, the ticket must be updated with the new part's lot/date code to maintain complete product genealogy.

5.5.2.26.3 MRB and the CAPA Loop

The true value of the logging system is realized when repeat failures are escalated for permanent correction via the Material Review Board (MRB) and CAPA.

A) MRB and Disposition

The MRB (Quality, Engineering, Materials) reviews non-conforming material to assign a final disposition based on risk, cost, and safety:

• Rework: (Standard fix applied and verified).
• Scrap: (Unrepairable; the CoPQ hit is recorded).
• Use-as-is: (Risk is documented and waived; customer approval often required).
• RTV (Return to Vendor): (Component/material issue; triggers a SCAR—Supplier Corrective Action Request).

B) CAPA and Effectiveness

A sustained or critical failure must trigger a CAPA (often structured as an 8D report). The ticket data provides the evidence for containment and root cause.

• Trigger: CAPA is initiated when the defect rate exceeds a predetermined threshold (e.g., >0.5% recurrence over 3 lots) or involves a high-risk failure mode (e.g., BGA-HIP).
• Root Cause: Use tools like 5-Why Analysis or Fishbone Diagrams to trace the fault from the test station back to the process (e.g., FCT power failure – ICT miss – SPI volume low – Clogged stencil aperture).
• Effectiveness Check: The CAPA closure cannot rely on simple sign-off. The system must define a metric (e.g., "Reduce BRIDGE-FP to ≤ 0.1% for the next 4 production lots") and verify that the metric is sustained over time.

Final Checklist: Repair and CAPA Discipline

Stage / Action	Mandate / Verification Point	Key Performance Indicator (KPI)
Logging	Every board failure auto-generates a ticket with SN, Defect Code, and Process Evidence (e.g., AOI image).	Aging Tickets (must be closed within 24/48 hours).
Rework	Rework technicians must follow Standard Work Instructions (WIs) and log all parts and heat cycles.	MTTR (Mean Time To Repair) by defect code; Repeat-Fail Rate (same SN, same fault).
Verification	Repaired boards must pass the failing test step again (no bypasses).	100% Retest completion rate logged in the MES.
MRB	Final disposition (Scrap/Rework/Use-as-is) is decided by the MRB based on risk and CoPQ.	Disposition Mix (Scrap rate trend); CoPQ (Cost of Poor Quality) total.
CAPA Loop	Recurring/critical failures must open a CAPA with a measurable Effectiveness Metric.	Top-10 Pareto defect frequency; CAPA Closure Rate (with verified effectiveness).