A component quality concern arrives after production has started. The purchase order shows the correct part number, and the warehouse balance is accurate. The difficult question is which received lot went into which build—and where the remaining material is now.
Component lot traceability depends on keeping those relationships intact. An order can arrive in several shipments, a reel can be divided, and a work order can draw from more than one lot. The useful record connects supplier evidence to each receipt, follows material movements, and identifies the production batches that may contain it.
For OEMs and contract manufacturers, the task is to make that chain survive normal operations. A folder of supplier PDFs helps only when the team can connect the documents to the physical stock and its use.
Keep the different identifiers separate
The manufacturer part number identifies the ordered component. A manufacturer lot or trace code identifies a production population under that manufacturer's system. A date code describes another characteristic of the material and may not uniquely identify a lot. Your receiving number identifies an internal receipt; it does not replace any of those source identifiers.
Manufacturer schemes differ. In its Aerospace and Defense supplement, section 25, Texas Instruments distinguishes QML lot-date-code practices from TI-defined lot trace codes used on other product categories. For the commercial-grade plastic products described there, TI says the associated date code serves inventory-age control and does not identify an individual lot.
Do not turn one manufacturer's example into a universal decoding rule. Preserve each field as supplied, including prefixes, suffixes, and leading zeros. If a field's meaning is unclear, ask the supplier or manufacturer for an explanation and retain the reply. Do not fill an unknown lot field by copying a date code into it.
A practical inventory system should therefore hold the internal receipt ID and the manufacturer's identifiers in separate fields. It should also distinguish the supplier's shipment or container reference from a manufacturer lot code when both are available.
Agree on the evidence before the shipment
State the traceability requirements in the sourcing request and confirm what the supplier can provide. Identify the exact component, the required source documentation, whether mixed lots are acceptable, and how quantities will be identified when more than one lot is supplied.
Ask which documents come from the manufacturer and which are issued by the supplying business. A document's issuer and stated scope matter. The same TI supplement describes a certificate of conformance and additional lot documents for QML-compliant devices, while non-QML shipping documents follow TI's standard practices. That is a product-specific distinction, not a universal document package for every semiconductor order.
Review each document for the requirement it actually addresses. A supplier declaration, packing list, and inspection report may answer different questions. Keep a report's sample identity, method, results, and limitations connected to the material it covers. Do not treat a matching filename or a general company certificate as a shipment-specific link.
If the required evidence is unavailable, resolve that gap through the agreed purchasing and quality process before release. A delivery deadline should not silently change the documentation requirement.
Create the receipt record while the source identity is available
Capture the information before external packaging and delivery paperwork become separated. Record the purchase-order line, supplier shipment reference, complete manufacturer part number, received quantity, available lot and date fields, and the relevant container or reel references. Associate the supporting documents with that receipt.
Manufacturer packaging information shows why the container reference matters. For the flip-chip products covered by STMicroelectronics application note AN4196, reel and carton labels include the part number, quantity, and traceability references. Use the current labeling guidance for the actual product rather than assuming every supplier uses that format.
Where your procedure permits, retain readable images of accessible labels. Keep the original label information visible when adding an internal inventory label. Verify the association between the label, physical container, and electronic record; attaching a photograph to the wrong receipt creates a convincing but unusable trail.
If an outer carton contains several identified packages, preserve their relationships instead of recording only the carton total. Follow the applicable handling procedure when information is inside protective packaging; opening it merely to complete a record may require additional controls.
A worked example: two receipts feeding two builds
Hypothetical example: A purchase order covers 1,000 pieces of one approved component. Receipt R-01 contains 600 pieces identified as manufacturer lot A. A later receipt, R-02, contains 400 pieces identified as lot B. The team records the following issues to production:
| Receipt and source lot | Received quantity | Issued to work orders | Stock balance |
|---|---|---|---|
| R-01 / lot A | 600 | 350 to WO-01; 150 to WO-02 | 100 |
| R-02 / lot B | 400 | 200 to WO-02 | 200 |
If a concern identifies lot A, the initial search finds 100 pieces in stock and material issued to both WO-01 and WO-02. Looking up only the purchase order would miss the difference between the two lots. Looking up only the latest receipt would miss earlier material used in WO-02.
The table does not prove which individual finished units contain lot A. That conclusion needs the corresponding production records. If WO-02 records only batch-level usage, its finished batch may remain within the potential exposure until the investigation establishes a defensible narrower scope.
Reconcile issued material with actual consumption, unused returns, scrap, and work in progress. The numbers are illustrative inventory movements, not production yield or test results. Quality decides the containment and disposition using the investigation evidence.
Preserve the parent link when stock is divided or returned
Give each new internal stock container a unique identifier linked to its parent receipt or container. Record the transferred quantity and the balance left behind. Keep the original manufacturer identifiers attached to both records; a new internal ID describes the split, not a newly manufactured lot.
This connection also matters when material goes to a contract manufacturer. Retain the dispatch reference and quantity, and agree how the receiving site will identify the material in its own system. Ask for the usage and return records needed to connect its work orders back to your supplied stock.
Seiko NPC's description of its traceability system provides a manufacturer example: records linked to lot numbers include division, shipping details, and outsourced receiving and shipping information. Your internal fields need to fit your process, but movements and divisions should preserve the earlier links.
For unused material returned from production, record its identity, quantity, condition, and review status. If the source lot cannot be established, flag the uncertainty and route it for assessment. Do not merge it into known stock merely because the part number matches. Apply the same discipline to material issued for rework or service repairs.
For feeder and carrier-format requirements, use the separate cut-tape and reel packaging guide. Here, the objective is preserving identity through the movement, regardless of the accepted supply format.
Test the trail in both directions
Choose a real receipt and ask the team to find its current stock, associated documents, production issues, and affected build records. Then choose a completed build and work backward to the received component lots. Include a split container or a production return in the exercise.
Record gaps explicitly: an unreadable source label, an overwritten lot field, a missing contractor usage record, or a batch that combines material without finer mapping. Assign an owner and correct the process that created the gap. A spreadsheet can support a small operation if identifiers and updates are controlled; software alone does not establish the missing relationships.
TI's Supplier General Quality Guidelines, section 21, illustrate this distinction through requirements for its own suppliers: unique lot or batch identification, process and quantity records, and identification of suspect material. Treat those as TI-specific requirements; define your own record scope and retention period through the requirements applicable to your products and customers.
Keep sourcing evidence and inspection decisions connected but distinct. Cplus Electronics describes inspection methods on its counterfeit-prevention page; discuss the required scope and records for the particular order. When submitting a component sourcing request, include your lot-identification and documentation needs alongside quantity and delivery requirements. The aim is material whose history remains usable after receipt, division, and production.
