9.4 Internal MRB & Quarantine Discipline

The Material Review Board (MRB) process is not a "repair shop" or a storage room for mistakes; it is a crime scene investigation. Every item in the MRB cage represents a failure of the process controls upstream. As a Quality Director, your mandate is simple: Segregation must be absolute. If a non-conforming part can be physically mistaken for a good part and re-introduced to the line, your Quality System has already failed. MRB is the "Air Gap" between a production anomaly and a customer escape.

Physical Segregation (The Red Cage)

Quarantine is not a status in the ERP system; it is a physical reality. Electronic blocking is insufficient because operators do not read SAP screens when grabbing a reel from a cart.

The "Red Cage" Standard:

• Physical Barrier: The Quarantine area must be a locked cage or a distinct room with controlled access.
• Visual Logic: All MRB material must be tagged with a RED "Non-Conforming" label immediately upon detection.
• Inventory Gap:
  • IF material is physically in the cage:
  • THEN it must be electronically transferred to the "MRB" or "Blocked" storage location in ERP.
  • Risk: If the physical and digital states drift, Planning will schedule production against bad inventory, causing line-down events.

The MRB Hierarchy (Disposition Logic)

The MRB is a decision-making body, not a committee for debate. The Quality Manager holds the casting vote. Use the following logic to disposition material efficiently:

• Disposition: Return to Vendor (RTV)
  • Trigger: Supplier defect confirmed.
  • Action: Issue SCAR + Debit Memo. Move to Shipping Dock within 48 hours.
• Disposition: Scrap
  • Trigger: Product cannot be recovered economically or safely.
  • Action: Mutilate before disposal. Do not just throw PCBs in a dumpster; they will be harvested for components on the gray market.
• Disposition: Rework
  • Trigger: Recoverable process defect (e.g., missing screw, cold solder).
  • Requirement: A documented Rework Instruction (WI) must be approved by Engineering before touching the unit. "Fix it" is not an instruction.
• Disposition: Use As Is (UAI)
  • Trigger: Cosmetic defect or minor deviation that affects form but not fit/function.
  • Requirement: Mandatory Engineering Deviation signed by the Design Authority. Quality cannot approve UAI alone.

MRB Aging & Velocity

The most common failure mode of an MRB system is the "Graveyard Effect"—parts enter and never leave. This hides WIP costs and obscures yield data.

The 30-Day Hard Stop:

• IF a discrepancy remains open > 30 days:
  • THEN it defaults to SCRAP.
  • Logic: If Engineering or the Supplier hasn't cared enough to resolve it in a month, the material is effectively dead. Stop paying to store it.
• Metric: Measure "Average Days in MRB." Target < 7 Days.

Scrap Security (Grey Market Protection)

High-value silicon and sub-assemblies are targets for theft. Scrapped material must be treated as "Hazardous Waste" in terms of chain of custody.

• Protocol: High-value scrap (CPU, Memory, Completed PCBAs) must be witnessed destroyed.
• Certificate of Destruction (CoD): Required for all proprietary or branded material.

Final Checklist

Control Element	Requirement	Critical Rule
Access Control	Physical Lock	Quality Personnel Only (Key/Badge access)
Identification	Tagging	Red Tag attached immediately upon failure
UAI Decision	Deviation	Engineering Signature Required (No verbal approvals)
Aging Limit	Velocity	> 30 Days = Automatic Scrap
Rework	Documentation	Approved WI Required before work begins
Disposal	Security	Mutilate/Crush to prevent resale