BOM & production release
PCBA Engineering Change Control: ECO, Revision & Cut-In
PCBA engineering change control keeps the approved design, purchased parts, work in progress and shipped assemblies aligned. A change is not complete when the new files are emailed; it is complete when the affected builds and their disposition are identifiable.
The practical decision
Use one change record to connect the old baseline, new baseline, approval and effective build boundary. Record what happens to old stock, open orders and boards already assembled before allowing the next release.
- IdentifyOld baseline + requested change
- AssessStock + WIP + test impact
- AuthorizeApprover + effective boundary
- VerifyFirst changed build + records
The minimum useful ECO record
For a component change, compare the baseline and candidate exports with the PCB BOM revision comparison. Attach the reviewed differences to the change record, then separately approve the design consequences and production cut-in.
An engineering change request proposes a change; an approved change order authorizes defined actions. Terminology varies between organizations. The important point is that a proposal cannot be mistaken for a released manufacturing instruction.
| Field | What to capture | Why it matters |
|---|---|---|
| Change identity | Unique change ID, reason and requester | Prevents informal changes becoming the only record |
| Baselines | Old/new PCB, BOM, drawing, firmware and test revisions | A change may affect more than one file |
| Affected population | Open orders, stocked parts, WIP and shipped lots | Defines containment and disposition |
| Validation | Required electrical, mechanical, assembly or software checks | Approval is supported by relevant evidence |
| Authorization | Decision, approver, date and conditions | Makes responsibility and scope explicit |
| Cut-in | First applicable order, lot or serial number | Distinguishes old and new configuration |
| Closure | Implemented records, verification and exceptions | Confirms the factory and documents agree |
For a component substitution, attach the alternative-parts approval record to the change package.
Example: connector change during a partial build
Illustrative scenario: 40 boards are assembled and the next 60 are still unbuilt when a connector is changed. First establish whether the old connector remains acceptable for the 40 units. Decide whether the new connector needs a drawing, footprint, height, harness or test update. Release the new BOM only after the technical decision. Label and document the two configurations, or authorize a controlled rework that brings them to one configuration.
Decide the fate of each affected population
鈥淯se the new version from now on鈥� is too ambiguous when different departments have different queues. Agree a build boundary that purchasing, production and shipping can all identify. Do not reuse an old board identifier if the change makes it misleading for service or traceability.
| Population | Decision options to document | Closure evidence |
|---|---|---|
| Parts on purchase order | Keep, cancel, substitute with approval or redirect | Revised order and supplier acknowledgement |
| Unused stock | Use within a limit, reclassify, return or dispose | Quantity and disposition record |
| Work in progress | Continue old revision, stop or rework | Traveler/release revision and affected lot |
| Completed assemblies | Accept as old build, rework or segregate | Final configuration and test evidence |
| Shipped product | Assess field impact through the customer process | Authorized communication and corrective action where needed |
Verify the first build after the change
Review the first applicable build against the released document set, then confirm purchasing, placement data, programming and test instructions all use the new baseline. Record required retesting after rework. Close the change only after the cut-in quantity and remaining old inventory are reconciled. Retain the old revision as history, while removing it from active production instructions.
Connect the effective build boundary to the lot and serial traceability records.
Working document
Prepare your handoff checklist
Open the editable text worksheet, save a copy and record the requirement, owner and evidence for each item. Keep unanswered points visible when requesting review.
- Change ID, reason and owner
- Old and new document manifest
- Affected orders, stock, WIP and shipped lots
- Technical impact and validation evidence
- Approval and conditional requirements
- Effective order/lot/serial boundary
- Stock and WIP disposition
- First changed build verification
- Closure owner and archived history
The Contact page is a separate enquiry step. Attach your completed worksheet and relevant files there using its available submission options; this page does not automatically transfer your answers.
Questions before you release the files
Does every file edit require a new production revision?
Use the agreed document-control policy. Any edit that changes the instructions used to build, inspect, program or accept the product needs a controlled decision and clear applicability.
Can the supplier implement an improvement without asking?
Define permitted process adjustments and approval-required changes in the agreement. Changes to customer-controlled design, materials or acceptance must follow the authorized process.
How does a component PCN relate to an ECO?
The component manufacturer鈥檚 notice is evidence to evaluate. The product owner decides whether it affects the assembly, what validation is needed and whether a controlled product change is required.
Continue with the next engineering task
Technical references
Example of original component-manufacturer change information; customer approval of a board-level change remains separate.