Using Lot Numbers as Serials: What It Means for RMAs in Cetec ERP
In regulated manufacturing environments, traceability isn’t optional: it’s a compliance requirement. But what happens when your traceability strategy collides with system logic?
Some manufacturers use lot numbers in place of serial numbers for items that don’t have truly unique serial IDs. While lot tracking makes sense from a process and documentation perspective, it can lead to challenges when multiple items share the same lot number. That’s especially true when that lot number gets entered into the serial number field.
Let’s break down the issue, and how to handle it in Cetec ERP.
The Scenario:
- You lot-track most of your products rather than assigning unique serial numbers.
- When a return (RMA) is processed, you track the item using its lot number entered into the serial number field.
- When pulling items for shipment, you encounter errors because Cetec sees duplicate “serial” numbers and won’t allow the same value to be picked twice.
You can check out Cetec ERP’s RMA Documentation here.
Why This Happens:
Cetec ERP enforces unique serial numbers for traceability. When the system sees the same value twice in the serial field - even if that value is really a lot code - it treats it as a conflict.
This creates a problem when two different physical items share the same lot number and that lot number is reused as their serial number.
The Solution:
If you’re running into errors pulling reworked or returned items due to serial number duplication, try this recommended order of operations in your RMA process to maintain traceability without causing conflicts:
- Start with the Source Invoice.
Go to the original invoice tied to the return.
Use the Create RMA link to ensure correct linkage between the return and the original shipment.
Learn how to generate RMAs & Rework Orders from an Invoice.
-
Create the RMA and Internal PO.
On the RMA object, generate the internal PO to receive the product back into inventory.
At this point, you can input the desired lot code. -
Create a Rework Order from the RMA.
This order will be recursive, meaning the received item itself will be picked to the rework order.
This keeps traceability intact throughout the process. -
Receive the Item Against the Internal PO.
Assign the correct lot number during this step.
This entry point ensures that the lot is properly tracked and associated with incoming inspections, receipts, and documentation. -
Pick the Reworked Item to the Rework Order.
The system pulls the correct traceability data (lot, serial, receipt, etc.) into the rework process.
This ensures compliance and simplifies audit trails. -
Complete and Ship the Reworked Product.
Once work is logged and parts are picked, ship the item and invoice as usual.
This workflow avoids the need to duplicate or workaround serial number conflicts while preserving the lot tracking you rely on.
Can You Use the Same Lot Number for Multiple Items in Cetec?
Yes - but not in the serial number field if those items are meant to be picked or processed simultaneously. Serial numbers must be unique within Cetec ERP for system consistency.
Recommendation:
- Use a consistent distinction between lot number and serial number fields.
- If needed, append an incremental suffix (e.g., LOT123-01, LOT123-02) when using lot codes in the serial number field to maintain uniqueness.
When lot numbers are treated as serial numbers, the system will enforce uniqueness—creating unintended conflicts if that logic isn’t accounted for. By using the RMA workflow in Cetec ERP and preserving unique serial entries, you can keep traceability intact and maintain process flow from returns to rework to reshipment.