AIAG CQI-11 Resistance Welding Audit: Automotive Supplier Guide

A resistance spot weld takes roughly 200 milliseconds. A CQI-11 audit failure can halt shipments for weeks. Most Tier 1 and Tier 2 automotive welding suppliers understand the physics of RSW — they understand far less about the audit mechanics that determine whether their process is classified as Acceptable or Unacceptable. This guide unpacks the CQI-11 framework, maps the Critical elements where most failures occur, and provides a pre-audit checklist quality engineers can act on immediately.

What Is AIAG CQI-11?

The Automotive Industry Action Group (AIAG) publishes the Resistance Welding System Assessment as CQI-11, part of its portfolio of special process standards. The series also includes CQI-15 for arc welding processes, CQI-12 for coating, CQI-17 for soldering, and CQI-23 for molding. Together these define how OEMs evaluate supplier manufacturing systems — not just product conformance.

CQI-11 applies to three resistance welding process families:

• Resistance spot welding (RSW) — dominant in body-in-white panel joining, door assemblies, and seat structures
• Projection welding — used for fastener attachment, bracket stacking, and nut/stud joining
• Seam welding — found in fuel tank fabrication, airbag housing, and seat belt anchor assemblies

If a component ships to an automotive OEM or Tier 1 and any of these processes are used, CQI-11 compliance is almost certainly contractual. Ford, GM, Stellantis, and most Asian OEM North American plants reference CQI-11 in their supplier quality manuals.

CQI-11 vs CQI-15: Scope and Overlap

Suppliers frequently confuse which standard applies. The decision point is the heat source:

A plant welding door hinges with RSW and seat frame rails with GMAW will be audited against both. The scoring framework is identical — a 1–4 scale, Critical element veto, customer-specific minimum overall score — so the audit preparation logic carries over. The technical content, however, does not: electrode tip dressing has no analogue in arc welding, and arc energy monitoring has no direct parallel in RSW.

The CQI-11 Scoring Framework

Each audit element receives one of four ratings:

Critical elements carry an automatic veto: a single score of 1 on any Critical item fails the entire assessment regardless of the total score. AIAG does not publish a public list of Critical elements — they are identified within the assessment form itself and vary by revision. As a rule, process parameter monitoring, calibration currency, and documented corrective action closures are always Critical.

The target overall score is customer-specific. Most OEM supplier quality manuals require ≥3.0 with no Critical element below 3. Ford Q1, GM BIQS, and Stellantis SCORE programs each add program-specific thresholds.

The Six Control Areas Auditors Examine

1. Welding Parameters and SPC

Auditors begin here. They compare the current machine settings — welding current (kA), weld time (cycles), electrode force (kN), and hold time — against the approved control plan and PPAP submission. Any deviation that was not processed through an approved change management procedure is an automatic finding.

Beyond parameter documentation, CQI-11 requires statistical monitoring of key parameters. SPC charts (X̄–R or individuals) for welding current and electrode force must be current, with control limits derived from process capability data — not engineering estimates. Gaps in SPC data entry, control limits set wider than the PPAP-approved tolerance, or charts with no evidence of review are high-probability Critical findings.

Calibration of the current monitoring and force measurement systems must be traceable to NIST or a national metrology institute equivalent, with calibration due dates visible at point of use.

2. Electrode Management

Resistance spot welding electrode tips degrade through thermal cycling and mechanical wear. Cap dressing (tip dressing) restores contact geometry and maintains weld consistency. CQI-11 auditors verify:

• Electrode dressing frequency defined and documented in the control plan
• Actual dressing intervals recorded per weld gun, per shift
• Electrode cap replacement criteria specified (number of dresses, contact diameter threshold)
• Cap replacement records retained and traceable to weld gun serial number

A common gap: electrode dressing is performed but not logged individually per gun. With 40–60 guns in a typical body shop, this produces an untraceable evidence gap that auditors flag immediately.

3. Weld Nugget Verification

The destructive verification section of CQI-11 is where the welding engineering team feels most confident — and where record-keeping gaps still cause failures. Auditors check:

• Peel test / chisel test frequency matches the approved control plan (e.g., first-off and every N joints, or every X minutes of production)
• Peel test results recorded with date, time, operator, equipment, and disposition
• Minimum nugget diameter criteria specified per weld class, traceable to the relevant drawing or standard (AWS C1.1 or ISO 14373)
• Cross-section metallographic samples for new programs or post-change qualification on file

4. Equipment Calibration

All measurement devices used to verify weld quality — force gauges, current monitors, weld timers, ultrasonic spot weld testers — must be on active calibration schedules. Auditors look for:

• Calibration labels physically present on equipment, or digital records accessible at the machine
• No expired calibration — a single expired gauge used in production is a Critical finding
• Calibration performed by accredited lab or traceable in-house system
• Gauge R&R studies on file for attribute gauges (plug gauges, go/no-go fixtures)

5. WPS and Procedure Documentation

Every production welding operation requires a current Welding Procedure Specification (WPS) based on a qualified Procedure Qualification Record (PQR). For resistance welding, qualification per AWS C1.1 (Recommended Practices for Resistance Welding) or ISO 14373 (Resistance Welding — Procedure for Spot Welding of Uncoated and Coated Low Carbon Steel) provides the technical basis.

Auditors verify that:

• WPS is posted or digitally accessible at each weld station
• WPS revision level matches the current PPAP-approved specification
• PQR is traceable to the WPS and retained in the quality record system
• Weld maps identify each weld joint by number, class, and acceptance criterion

6. Personnel Qualification and Training

Weld operators and setup personnel must have documented qualification for each process and equipment type they operate. Training records must include initial qualification date, refresher intervals, and any customer-specific certification requirements. Auditors check that records are current — not just that they exist.

For automated resistance welding systems, technician qualification for robot programming, PLC parameter management, and error-proofing system verification is also within scope.

Pre-Audit Checklist — Evidence Matrix

Digital Evidence Collection for CQI-11

Paper-based evidence management fails CQI-11 audits at scale. With 40+ weld guns, multiple shifts, and hundreds of peel tests per week, manual log aggregation produces exactly the traceability gaps auditors find most often.

Digital welding quality systems address this directly. Inline monitoring of weld current, force, and time — captured per weld, per gun, per part number — provides the SPC data CQI-11 requires as a byproduct of production, not as a parallel documentation burden. Electrode dressing events triggered by the process controller and logged automatically eliminate the per-gun record gap. Peel test results entered at the station with barcode scan traceability produce an audit-ready record without manual transcription.

Linking this process data to ISO 3834 traceability records and the overall quality management system completes the evidence chain auditors expect to see in a Superior-rated operation.

For suppliers managing both RSW and arc welding — the most common automotive scenario — a single monitoring platform covering both process families reduces the documentation overhead for simultaneous CQI-11 and CQI-15 assessments.

From Needs Improvement to Acceptable: The Corrective Action Path

A CQI-11 score of 2 on a non-Critical element triggers a formal corrective action plan with a customer-agreed closure date. The corrective action must address root cause — not just the evidence gap. Rewriting a calibration label on an expired gauge does not close a calibration finding; demonstrating a calibration schedule that prevents recurrence does.

The fastest path from Needs Improvement to Acceptable is evidence-first: show the auditor the corrected record, the updated procedure, and the monitoring mechanism that prevents recurrence, in that order. Auditors close findings on evidence, not intent.