6.10 Line Returns, Scrap & Nonconforming Material Flow

The "Reverse Flow" (Production → Warehouse) is where inventory accuracy usually dies. Operators under pressure tend to dump unused parts, empty reels, and scrap into a pile and sort it out "later." "Later" never comes. The result is "Mystery Inventory"—parts that physically exist but are chemically expired, electrically damaged, or digitally invisible.

You must enforce a strict "No ID, No Entry" policy. The warehouse is not a trash can; it is a bank vault. Only verified assets are allowed back in.

The Triage Gate: Good vs. Bad vs. Suspect

Do not mix these streams. Each requires a different physical path and system transaction.

Return to Stock (Good Material)

• Criteria:
  • Part is undamaged and clean.
  • Traceability is intact: The Manufacturer Label is present.
  • MSD Status: Part has been re-sealed with desiccant/HIC (if required).
  • Leader Length: There is enough leader tape (e.g., > 200mm) to allow re-loading on a feeder.
• Action: Count → Re-label (if open) → Transact "WIP-to-Stock" → Put away.

Scrap (Confirmed Bad/Excess)

• Criteria: Damaged leads, short tape strips (too short for feeder), floor sweepings, or setup waste.
• Action:
  • Do not return to the warehouse shelf.
  • Record the loss in the MES/ERP against the specific Work Order (Yield Loss).
  • Physically destroy/discard into the Scrap Bin immediately.

Nonconforming / Suspect (MRB)

• Criteria: "It didn't work on the board," "Feeder jammed," or "Looks oxidized."
• Action:
  • Isolate in a RED bin or bag.
  • Move to Quarantine (See Section 6.3).
  • Do not Scrap yet. Engineering must investigate to see if the whole reel is bad (Supplier Quality issue).

The "Minimum Usable" Rule

Stop storing trash. It costs money to count, store, and insure material that you can never actually use.

• SMT Reels:
  • If remaining quantity < 50 pieces (or feeder minimum) → Then Scrap. Do not put a 2-inch strip of tape back on the shelf.
• Tubes/Trays:
  • If a tube is bent or a tray is cracked → Then Transfer parts to a good carrier or Scrap. A damaged carrier will jam the pick-and-place machine next time.

Labeling & Identification Discipline

A return without a label is immediate scrap.

• The "Orphan" Strip:
  • Scenario: Operator cuts a reel to fit a custom feeder and returns the tail end without a label.
  • Outcome: Scrap. You cannot guess the Lot Code.
• Repackaging:
  • If the original bag is torn → Then Repackage in a new ESD bag.
  • Mandatory Label: Must show MPN, Qty, Date Code, and Lot ID. Writing "100 pcs" with a sharpie on the bag is not compliant.

System Hygiene & Reconciliation

The physical return must match the digital credit.

• The "WIP Flush":
  • At the end of a build, the WIP location for that line must be Zero.
  • Formula: Issued Qty - Goods Produced (consumed) - Scrap Reported - Returns to Stock = Variance.
  • If Variance ≠ 0 → Then Inventory is missing. Investigate immediately. Do not close the WO until resolved.

Final Checklist