Trace one suspect lot through split, merge and rework

Trace one suspect lot through split, merge and rework

Product traceability preserves identity through changes in material and work. A useful trace links inputs to outputs in both directions and follows splits, merges, rework and shipments. Start a drill with a clearly scoped suspect input or output, then collect the linked records and reconcile quantities and locations. A balanced total is necessary but not sufficient: records may still name the wrong destination or omit a rework link. Record gaps and improve the capture process before an actual containment event. The method supports locating affected product; it is distinct from metrological traceability, which concerns the reference chain and uncertainty of a measurement result.

Follow the method

1. Input lot: 400
2. Split: 250 + 150
3. Processing + rework
4. Shipped 300 / WIP 80 / scrap 20
5. Learn from trace gaps

Reconcile the material and prove where it went

Fictional case: input lot L70 contains 400 units and splits into path A250 and path B150. The retained core totals are 300 shipped,80 in work and 20 scrapped. Trace coordinator Luis must identify where suspect material went. A balanced total is available, but one shipment record lacks its destination identity.

Follow the method

1. Path A
2. Path B
3. Overall
4. Rework/merge

Four hundred accounted for is only the first check

Trace a suspect lot through both quantity and identity links, including split paths, destinations, WIP and scrap.

Fictional case: input lot L70 contains 400 units and splits into path A250 and path B150. The retained core totals are 300 shipped,80 in work and 20 scrapped. Trace coordinator Luis must identify where suspect material went. A balanced total is available, but one shipment record lacks its destination identity.

Role: Trace coordinator with warehouse, production and quality owners

Normal condition

Every transformation or movement preserves source/output identity, quantities, status and destination. Rework links do not create or erase material.

The gap

The team declares the trace complete because 300+80+20=400, even though the recipient of part of the shipped population is unresolved.

• Quantity balance is necessary but not sufficient for trace completeness.
• The example is a drill; actual containment or notification follows applicable authority.

1. Define the suspect identity and direction

   Luis identifies L70 and the reason for the trace, then follows both upstream and downstream links relevant to the scope. He records the starting evidence and any uncertainty.

   Why: A trace needs a precise starting identity. Searching only a convenient downstream batch can miss other descendants of the same input.

   Evidence: The drill scope names L70 and both split paths.

2. Follow each split independently

   He reconciles A as 200+40+10=250 and B as 100+40+10=150. He retains the path identities rather than merely summing the plant-wide totals.

   Why: Separate reconciliation exposes a missing or duplicated path that a coincidentally balanced total could hide.

   Evidence: Both paths have linked output/status records.

3. Locate shipments and current stock

   For the 300 shipped units, Luis verifies shipment IDs, destinations and quantities. He locates the 80 WIP units and verifies the 20 scrap records and actual disposition evidence.

   Why: A quantity without a destination cannot support a complete exposure response. WIP and scrap labels need real identity/status evidence.

   Evidence: Every known quantity has a location or retained destination record, except the declared gap.

4. Include rework and merges

   He checks whether either path entered rework or merged with other lots. Rework is a status/process link, not extra production to add to the total.

   Why: A material path can be correct arithmetically yet broken genealogically. Merges can extend the set of affected outputs beyond a simple two-branch drawing.

   Evidence: The trace record contains explicit rework/merge checks rather than an assumption of none.

5. Resolve gaps before declaring completion

   Luis reports the missing destination as unresolved, assigns the warehouse owner and preserves the balanced quantity evidence. Quality determines any required response using the actual scope.

   Why: A truthful partial trace is more useful than a false complete label. Closure requires identity, destination and disposition evidence as well as arithmetic.

   Evidence: The drill record states what is known, what remains uncertain and who resolves it.

A rework batch contains material from two lots

Path B material was merged with a second input lot during rework.

Trace the merged output identity and quantities for both inputs, and determine affected downstream scope through the authorized quality process.

A merge creates a relationship to retain, not permission to assign all output to one convenient original lot.

The record links both parent lots to the reworked output and its destinations.

Run a practice session

Materials

• Lot/path cards
• Movement ledger
• Blank trace-gap record

1. Define the starting scope · 5 minutes

   Which descendants must be followed?

2. Reconcile both paths · 8 minutes

   Can the total balance while one path is wrong?

3. Resolve L91 · 10 minutes

   What does the rework note actually prove?

4. Debrief closure · 5 minutes

   Which destination evidence remains necessary?

Debrief

• Ask learners to identify mutually exclusive current statuses.
• Keep notification decisions with the authorized quality owner.

Draw the lot links, then attach each quantity to a verified status and destination.

Transfer into the work

Owner: Traceability owner with warehouse and quality

Record: Genealogy, movement, status and drill-gap records

Review: At defined trace drills and after relevant process/record changes

Evidence: Complete identities, quantities and destinations across split/merge/rework

Repair record capture and verify a new trace opportunity when a drill exposes missing links.