AIAG CQI-15 Welding System Assessment — Complete Guide for Tier 1 Suppliers

Automotive customers expect welding suppliers to pass CQI-15 assessments with minimal preparation time and zero Critical findings. Most suppliers that fail do so not because their welding quality is poor, but because the documentation and monitoring evidence required by the standard is incomplete, inconsistent, or trapped in paper records that cannot be retrieved during a live audit. This guide covers the full CQI-15 framework — what it measures, how OEM customers apply it, and where digital process monitoring turns audit preparation from a fire drill into a controlled routine.

What Is AIAG CQI-15?

The Automotive Industry Action Group (AIAG) publishes the Welding System Assessment as part of its special process assessment series, alongside CQI-11 (plating), CQI-12 (coating), CQI-17 (soldering), and CQI-23 (molding). CQI-15 was first released in 2011 and is periodically revised to reflect advances in joining technology and evolving OEM quality expectations.

The standard evaluates the welding system — not an individual weld or a single production run — across five categories: Management Responsibility, Process Control, Monitoring and Measurement, Corrective Action, and Continual Improvement. Each category contains elements, some of which are designated Critical, meaning a score of Unacceptable on any Critical element fails the entire assessment regardless of performance in other areas.

The Five Assessment Categories

Category 1 — Management Responsibility

This category verifies that welding quality is owned at the management level, not treated as a purely technical function. Auditors look for:

• A documented welding quality policy referenced in the overall quality management system
• Designated welding coordination personnel with roles aligned to EN ISO 14731 (Welding Coordination — Tasks and Responsibilities)
• Management review records that include welding-specific KPIs: scrap rate, rework hours, non-conformance closure rate

Many suppliers underperform in Category 1 because welding responsibility is distributed across process engineers, quality managers, and production supervisors without a single accountable owner. CQI-15 expects a named Welding Responsible Person (WRP) with documented authority.

Category 2 — Process Control

Category 2 is where most Critical elements live. It covers:

• Welding Procedure Specifications (WPS): Must be documented, approved, and accessible at the point of use. Qualified per ISO 15614-1 or customer-approved equivalent. Digital WPS management eliminates the version-control problem that causes frequent findings.
• Welder and operator qualification: Current qualification records for every operator performing regulated welds. Expiry dates must be tracked proactively, not discovered during the audit.
• Equipment calibration and maintenance: Calibration currency for power sources, wire feeders, torches, and fixtures. Maintenance logs demonstrating scheduled preventive maintenance.
• Process parameter limits: Documented acceptable ranges for voltage, current, travel speed, wire feed rate, shielding gas flow, and preheat/interpass temperature per ISO 13916. Parameter limits must be enforced at the machine, not just recorded on paper.

Category 3 — Monitoring and Measurement

This is the category most directly impacted by the shift to inline digital monitoring. Requirements include:

• Per-weld process data: Evidence that key parameters were within spec for every production weld, not just sample welds. Manual logging fails this at scale — a 500-joint body panel welded over an 8-hour shift generates more log entries than any operator can accurately maintain.
• Calibrated measurement equipment: Gauges, thermometers, flowmeters, and sensors used for process monitoring must have current calibration records traceable to national standards.
• Traceability to production records: The ability to link a specific weld anomaly back to the operator, machine, shift, and parameter set in force at the time of welding. This is the foundation of effective root cause analysis under 8D.

Inline thermal monitoring systems address Category 3 by generating continuous, per-weld records of heat input, temperature gradients, and solidification signatures — automatically timestamped and linked to part IDs. See our inline weld monitoring overview for how this integrates with existing MES infrastructure.

Category 4 — Corrective Action

Category 4 assesses whether the supplier’s corrective action system is functional, not just documented. Auditors verify:

• Open corrective actions from previous CQI-15 assessments have been closed with verified effectiveness
• 8D or equivalent methodology is applied to welding non-conformances, with root cause drill-down to process parameter level
• Customer notifications were issued within required timeframes for any suspect product shipped

The most frequent gap here is containment verification: the supplier documents that defective parts were reworked but cannot demonstrate that the process condition that caused the defect was actually corrected at the machine.

Category 5 — Continual Improvement

The final category looks for evidence of proactive quality improvement rather than reactive firefighting. Acceptable evidence includes:

• Trend analysis on welding defect rates with documented improvement targets
• Capability studies (Cpk/Ppk) on Critical-to-Quality welding parameters
• Participation in AIAG or OEM welding forums, updated training records, adoption of revised standards

OEM-Specific Overlays

All major North American and European OEMs use CQI-15 as a baseline but layer additional requirements on top:

Suppliers serving multiple OEMs should map their quality system once to CQI-15 categories and then document customer-specific evidence in a gap matrix to avoid duplicating preparation effort.

How Digital Monitoring Closes the Evidence Gap

The shift from paper-based to digital process monitoring directly resolves the most common CQI-15 failure modes:

1. Automated parameter logging eliminates the manual recording gap in Category 3. Every weld generates a timestamped record without operator intervention.
2. Alarm management with closed-loop response demonstrates Category 2 compliance at the machine level — out-of-spec parameters are flagged in real time, not discovered at end-of-shift inspection.
3. Searchable weld history enables the traceability evidence required in Category 4 corrective actions. An auditor asking “show me the process data for this rejected assembly” receives a filtered report in seconds rather than a paper search through shift logs.
4. Statistical process control dashboards provide the Cpk/Ppk evidence expected in Category 5 without additional data collection effort.

For a detailed audit-item-level checklist mapping CQI-15 elements to specific evidence requirements, see our CQI-15 audit checklist guide.

Preparation Roadmap: 90 Days to Audit-Ready

The 90-day timeline is conservative — suppliers with ISO 3834 or EN 15085 certification in place will find many Category 1 and 2 requirements already documented. The critical gap is almost always Category 3 monitoring evidence, particularly the per-weld parameter records.

Key Takeaways

• CQI-15 is a five-category system audit, not a weld inspection protocol — evidence of how the system works matters more than individual weld appearance.
• Critical elements in Category 2 and 3 are automatic failure triggers; prioritise these in any gap assessment.
• Digital inline monitoring solves the per-weld parameter evidence requirement that manual logging cannot reliably satisfy at production volumes.
• ISO 3834 and CQI-15 are complementary: build the QMS to ISO 3834, demonstrate it audit-ready via CQI-15.