4.5 Supplier corrective action and effectiveness check
A Supplier Corrective Action Request (SCAR) is not merely an administrative complaint form; it is a formal demand for a systemic engineering change. If a supplier is simply instructed to “fix the bad parts,” they are perfectly positioned to rework the current inventory and potentially ship the exact same defect next month. The fundamental goal of a SCAR is to forcefully drive a permanent improvement in the supplier’s overall process so that the specific defect becomes impossible to reproduce.
SCAR triggers (when to pull the alarm)
Section titled “SCAR triggers (when to pull the alarm)”Care must be taken not to dilute the impact of a SCAR by issuing one for every minor, one-off discrepancy. They should be reserved for situations where process capability has measurably degraded or systemic risks are exposed.
The Escalation Logic:
- Level 1: Critical (Stop Ship)
- Trigger: Safety hazards, Regulatory violations (e.g. RoHS/REACH compliance failures), or any severe defect resulting in a “Line Down” event lasting > 4 hours.
- Response: A 24-hour Containment (D3) plan from the supplier is mandatory.
- Level 2: Major (Systemic)
- Trigger: A repeat defect (the identical MPN and failure mode occurring within a 90-day window) or an incoming Defect Rate exceeding 1%.
- Response: A comprehensive 8D Report is required to find the true root cause.
- Level 3: Minor (Trend)
- Trigger: Persistent documentation errors (like missing CoCs) or a slow, negative trend in the Supplier Scorecard metrics.
- Response: A standard, simpler Corrective Action Plan (CAP) format is usually acceptable here.
The 8D methodology (mandatory architecture)
Section titled “The 8D methodology (mandatory architecture)”Formal, recurring issues require a formal, structured architecture to solve them. Brief “email explanations” for critical failures are not accepted. Suppliers should be required to structure their response using the standard Eight Disciplines (8D) methodology.
- D3: Interim Containment (The Tourniquet)
- Requirement: The problem must be isolated immediately. The supplier must explicitly define how they screened their suspect stock (e.g. “100% visual inspection under 4x magnification”) and how they identified the verified clean boxes being shipped (e.g. “A Green Dot was placed on the shipping label”).
- Deadline: Usually expected within 24 Hours.
- D4: Root Cause Analysis (The Pathology)
- Core Principle: “Operator Error” is almost never a valid Root Cause. If an operator made a mistake, the process failed to prevent or detect that mistake.
- Tools: Suppliers should provide documented evidence of a 5 Whys or Fishbone (Ishikawa) analysis.
- Poor D4: “The worker didn’t follow the SOP.”
- Good D4: “The assembly fixture allowed the part to be loaded backwards because it lacked a mechanical keying pin.”
- D5/D6: Permanent Corrective Action (The Fix)
- Goal: A systemic or hardware change is expected, not just behavioral retraining.
- Hierarchy of Intervention: 1. Poka-Yoke (Mistake Proofing): Physical modification to the tooling (Strongest). 2. Process Change: Implementation of Automated Optical Inspection (AOI) or sensors (Strong). 3. Training: An informational update via a team meeting (Weakest - The SCAR must be rejected if this is the entirety of the proposed action plan).
- D7: Prevention (System Update)
- Requirement: The corrective action must propagate down to the core line documentation. Updates to the supplier’s PFMEA (to demonstrably lower the Occurrence or Detection risk scores) and the corresponding updates to the Control Plan are expected.
Effectiveness verification (VoE)
Section titled “Effectiveness verification (VoE)”A SCAR is never closed based simply on a promise; it is closed exclusively on physical evidence.
The “3-Shipment” Rule:
- Guideline: Once a Permanent Corrective Action (PCA) is allegedly implemented, the SCAR enters a “Monitoring” state.
- Action: The subsequent 3 consecutive shipments from the supplier must show zero defects for the specific characteristic that triggered the SCAR.
Re-Open Logic:
- Guideline: If the exact same defect recurs within 6 months, the previous SCAR was inherently ineffective and the root cause was missed.
- Action: The issue must be re-opened immediately as a Level 1 Escalation. In this scenario, it is often appropriate to require the supplier’s Quality Director to formally present their revised remediation plan directly to Management.
Recap: Supplier Corrective Action and Effectiveness Check
Section titled “Recap: Supplier Corrective Action and Effectiveness Check”| Parameter | Requirement | Value / Condition | Action / Verification |
|---|---|---|---|
| SCAR Trigger (Level) | Critical (Stop Ship) | Safety/Regulatory violation or Line Down >4 hours | Issue SCAR; Mandatory 24-hour D3 containment plan |
| Major (Systemic) | Repeat defect (same MPN/failure within 90d) or Incoming Defect Rate >1% | Issue SCAR; Mandatory complete 8D report | |
| Minor (Trend) | Persistent documentation errors or negative scorecard trend | Issue standard Corrective Action Plan (CAP) | |
| 8D Response (D3-D7) | D3: Interim Containment | Isolate suspect stock; define screening method & marking | Submit plan within 24 hours (Critical) |
| D4: Root Cause Analysis | Reject “operator error”; use 5 Whys/Fishbone with evidence | Document systemic cause in process/equipment | |
| D5/D6: Permanent Corrective Action | Hierarchy: 1. Poka-Yoke, 2. Process Change, 3. Training (not sole action) | Implement systemic/hardware change; reject training-only plans | |
| D7: Prevention | Update PFMEA (lower risk scores) and Control Plan | Submit revised documentation as evidence | |
| Closure & Verification | Effectiveness Check | 3 consecutive defect-free shipments post-PCA | Perform 100% IQC inspection on probationary shipments |
| Re-Open Criterion | Same defect recurs within 6 months | Re-open as Level 1; require Quality Director presentation |