Document everything first
Before you tell the current manufacturer you are leaving, document what they have. They may become less helpful once they know the contract is ending.
What to document:
- Latest BOM with all MPNs and approved alternates
- Latest gerbers, ODB++, IPC-2581
- Assembly drawing, mechanical drawing, packaging spec
- Test plan, FCT vector list, test fixture CAD if you own it
- Firmware binary, source repo access, signing key list
- PKI structure for secure provisioning
- Per-unit traceability data export
- Component lot data for last 6 months
- Yield and defect data for last 6 months
If any of this lives only with the manufacturer, get a copy now.
Test fixtures
Test fixtures are the hardest item to transfer. Custom bed-of-nails or edge-connector fixtures are often built by the manufacturer's test engineering team and may not transfer easily.
Options:
- You own the fixtures: ask for them back as part of the transfer
- Manufacturer owns the fixtures: replicate them at the new manufacturer (4 to 8 weeks NRE typically)
- Modular fixtures: easier to replicate
Plan for fixture replication time in the transfer schedule.
Signing keys
Firmware signing keys, secure boot keys, and PKI root keys must transfer through controlled escrow, not by email.
A workable pattern:
- Keys held by buyer in HSM
- Production line accesses signing through API
- Transfer means changing API access, not transferring keys themselves
If keys live on the current manufacturer's line and not in your HSM, that is a sign that the security architecture needs work before the transfer.
Per-unit traceability data
Export the per-unit traceability database before transfer. This is your record of what shipped, with what firmware, against which signing keys. You may need it years later for security update notifications or warranty claims.
Pilot at the new manufacturer
Do a pilot batch at the new manufacturer before cutting over production. The pilot validates:
- DFM gaps between the two lines (component placement tolerances differ between machines)
- Test fixture replication accuracy
- Provisioning workflow fidelity
- Component sourcing alignment
Pilot batch typically 100 to 500 units. Compare to golden samples from the current manufacturer.
Cutover plan
Common patterns:
- Cold cutover: stop primary, start secondary on next batch (riskiest)
- Phased cutover: split allocation 70/30 or 50/50 for a few batches, shift to 100 percent over time (lower risk)
- Parallel run: both lines build for one batch, compare results (highest cost, lowest risk)
For high-stakes products, phased cutover is the default.
Notification timing
Notify the current manufacturer once you have your documents and a pilot timeline. Earlier notification gives them more time to be unhelpful.
What good transfer looks like
- Documentation complete before notifying current manufacturer
- Test fixtures replicated at new manufacturer before pilot
- Pilot batch run and compared to golden samples
- Phased cutover, not cold
- Per-unit traceability data exported and archived
- Signing keys never traveled by email