4.5 Supplier Corrective Action (SCAR/8D) + Effectiveness Check

A Supplier Corrective Action Request (SCAR) is not a "complaint form" or an invitation to apologize. It is a formal, legal demand for a systemic engineering change. If you merely ask a supplier to "fix the part," they will rework the inventory and ship you the same defect next month. The goal of a SCAR is to force a mutation in the supplier's process so that the defect becomes physically impossible to produce.

SCAR Triggers (When to Pull the Alarm)

Do not dilute the power of a SCAR by issuing one for every minor scratch. Use them when the process capability has collapsed.

The Escalation Logic:

• Level 1: Critical (Stop Ship)
  • Trigger: Safety hazard, Regulatory violation (RoHS/REACH), or any defect causing a "Line Down" event > 4 hours.
  • Response: 24-hour Containment (D3) is mandatory.
• Level 2: Major (Systemic)
  • Trigger: Repeat defect (same MPN, same mode within 90 days) or Defect Rate > 1%.
  • Response: Full 8D Report required.
• Level 3: Minor (Trend)
  • Trigger: Documentation errors or negative trend in Supplier Scorecard.
  • Response: Informal Corrective Action Plan (CAP) accepted.

The 8D Methodology (Mandatory Architecture)

We reject "email explanations." Suppliers must submit their response using the standard Eight Disciplines (8D) structure.

• D3: Interim Containment (The Tourniquet)
  • Requirement: Isolate the victim. The supplier must define exactly how they screened suspect stock (e.g., "100% visual check under 4x magnification") and how they marked the clean boxes (e.g., "Green Dot on label").
  • Deadline: 24 Hours.
• D4: Root Cause Analysis (The Pathology)
  • Rule: "Operator Error" is NOT a Root Cause. If an operator failed, the process failed to prevent the error.
  • Tools: Must show evidence of 5 Whys or Fishbone (Ishikawa) analysis.
  • Bad D4: "Worker didn't follow SOP."
  • Good D4: "Fixture allowed part to be loaded backwards because there was no keying pin."
• D5/D6: Permanent Corrective Action (The Fix)
  • Goal: Hardware change, not software/wetware change.
  • Hierarchy of Intervention:
    1. Poka-Yoke (Mistake Proofing): Physical modification (Strongest).
    2. Process Change: Automated inspection/sensors.
    3. Training: Informational update (Weakest - Reject if this is the only action).
• D7: Prevention (System Update)
  • Requirement: The fix must propagate to the documentation. Update the PFMEA (to lower Occurrence/Detection scores) and the Control Plan.

Effectiveness Verification (VoE)

A SCAR is never closed on a promise; it is closed on evidence.

The "3-Shipment" Rule:

• IF PCA is implemented -> THEN SCAR enters "Monitoring" state.
• Action: The next 3 consecutive shipments must be defect-free.
  • Pro-Tip: Tag these shipments in the ERP system as "Probationary." IQC must perform 100% inspection on the specific characteristic that failed.

Re-Open Logic:

• IF the defect recurs within 6 months -> THEN The SCAR was ineffective.
• Action: Re-open as Level 1 Escalation. The supplier's Quality Director must present the new plan to our Senior Management.

Final Checklist