A coatings batch reaches the bottom of one pigment container before the required quantity is complete. A second container carries the same material code but a different supplier lot. Production keeps moving, yet the batch record says only “120 kg blue pigment.”
The formula quantity may be correct, but the history is incomplete. A useful split pigment lot reconciliation must show how much each lot contributed, when it entered the batch, what was returned to stock, which checks followed the change, and which finished inventory carries both lots.
Why “same pigment, two lots” still needs two records
A material code identifies the approved item. A supplier lot identifies a particular production event from that supplier. Two containers can share the item name and specification while carrying different lot numbers, receipt dates, or internal status histories.
Combining both lots on one line removes the relationship between quantity and identity. If a supplier later asks about lot B, the team may not know how much entered this batch or when the container changed.
Keep the formula line unchanged: the approved requirement is still 120 kg of the specified pigment. Under that line, create a separate actual-use record for every raw material lot.
For the broader chain around receiving, formula versions, quality, and packaging, see the ink and coatings record-flow map. It shows how ink manufacturing records connect beyond this split-lot event.
Confirm the second lot before it enters the batch
A matching item code is not, by itself, permission to add a new container. Follow approved material-status, safety, and quality procedures. Before use, confirm:
- material code and description;
- supplier lot and internal material-lot ID;
- receipt and release status;
- container identity and storage location;
- quantity available in the correct unit;
- person who verified the lot for use;
- time the verification occurred.
Workplace labels, safety data sheets, training, and hazard-communication procedures remain separate safety responsibilities. The production ledger should not replace them.
If the lot is unavailable under the business’s rules, stop the issue rather than hiding the decision inside a later note. The incoming raw-material lot guide explains pigment lot tracking and how to preserve supplier and internal identities before production starts.
Build a material balance for each lot
Use the same unit for the formula requirement, issue, return, and net addition.
For each lot:
Net quantity added = quantity issued − quantity returned − documented loss outside the batch
Suppose the formula requires 120 kg of pigment. Production uses the remainder of lot A, then opens lot B.
| Pigment lot | Issued to batch area | Returned to stock | Documented outside-batch loss | Net added |
|---|---|---|---|---|
| Lot A | 40 kg | 2 kg | 0 kg | 38 kg |
| Lot B | 85 kg | 3 kg | 0 kg | 82 kg |
| Total | 125 kg | 5 kg | 0 kg | 120 kg |
The two net additions reconcile to the approved 120 kg requirement. Inventory should decrease by 38 kg for lot A and 82 kg for lot B—not by one anonymous 120 kg issue.
If the quantities do not balance, do not force the totals to match. Look for an unrecorded return, spill, sample, transfer, tare error, unit conversion, or data-entry mistake. Record the reason and reviewer.
Keep addition timing and sequence visible
Quantity alone does not reconstruct the run. In the actual-use section of the coatings batch records, capture:
- lot ID;
- actual quantity added;
- addition start or completion time;
- operator;
- equipment or vessel when relevant;
- sequence step;
- observation or reading tied to that point;
- any hold, review, or authorized adjustment.
For example, “Lot A, 38 kg, addition complete 10:12” and “Lot B, 82 kg, addition complete 10:29” are more useful than one end-of-shift total. Give each sample its own ID and time.
Do not rewrite the approved pigment formula to make actual events look planned. The master remains the standard. The batch ledger shows what happened. If repeated evidence supports a controlled change, review it through the business’s formula-version process.
Connect both lots to quality and finished inventory
The split-lot record should continue forward. Quality results need the production batch ID and sample ID. A release, hold, rework, or rejection should point to its evidence and reviewer.
Packaging records then connect the bulk batch to finished-lot codes and quantities. If the whole batch used both pigment lots, every finished lot produced from that bulk batch inherits that relationship. If part of the bulk was held, reworked, or packaged separately, preserve those branches rather than treating all output as one undifferentiated quantity.
This is the purpose of paint batch traceability: trace either pigment lot to the affected batch and finished inventory, then trace a finished container backward to both raw material lots.
For a related example of preserving corrections without erasing batch history, use the custom-color reorder reconciliation.
Run a pre-release split-lot audit
Before the batch is released, ask one reviewer to check five controls:
- Identity: Are both supplier and internal lot IDs present?
- Balance: Do issue minus return and documented outside-batch loss equal net addition for each lot?
- Formula: Do the combined net additions reconcile to the approved requirement or an authorized deviation?
- Timeline: Can the reviewer place each lot addition, sample, and adjustment in order?
- Forward link: Can both pigment lots be traced to every resulting finished lot or held quantity?
Mark missing facts while the containers, scale tickets, operators, and samples are still available. Reconstructing them weeks later invites confident guesses.
Kerno can help connect material lots, formula versions, batch activity, costing, quality checks, and finished inventory. Whatever system the business uses, the control is the same: preserve each lot as a separate quantity-bearing relationship.
Frequently asked questions
Can two supplier lots of the same pigment share one line on the batch record?
Keep them as separate actual-use lines. The formula may have one material requirement, but each supplier or internal lot needs its own identity, quantity, and event record.
Should using a second pigment lot create a new formula version?
Not automatically. The approved formula identifies the material requirement. The batch record identifies the actual lots used. A formula revision should follow the business’s separate review and approval process.
What if issued quantity and actual added quantity do not match?
Record returns, outside-batch loss, samples, transfers, or corrections explicitly. Investigate any remaining difference rather than changing the added quantity simply to make inventory balance.
Does a split-lot record prove the two lots are interchangeable?
No. It proves which lots were used and in what quantities. Material approval, specifications, testing, safety, and suitability decisions must follow the business’s applicable procedures.
Practical takeaway
Choose one recent batch that used two lots of the same material. Reconcile issue, return, loss, and net addition by lot. Then trace both lots forward to the batch decision and finished inventory. If any step depends on memory, add the missing field before the next run.
