The strongest supply chains in the US, EU, UK and Japan are rarely single-origin. Instead of choosing between importing or manufacturing from Thailand and keeping production at home, mature buyers run both and allocate volume by rule.
Why dual sourcing wins
- Cost anchor. A qualified Thai source disciplines domestic pricing.
- Continuity. A strike, fire or tariff shock at one origin does not stop shipments.
- Speed vs cost split. Domestic covers rush and low-volume specials; Thailand covers forecastable base volume.
- Customer assurance. Enterprise and retail customers increasingly ask for a documented second source.
Allocation rules that work
| Demand type | Origin | Typical share |
|---|---|---|
| Forecastable base volume | Thailand | 60-80% |
| Rush / short-lead orders | Domestic | 10-25% |
| New SKU pilots | Domestic first, then transfer | 5-15% |
| Highly customised units | Domestic | as needed |
Write the rule into your planning system so allocation is not renegotiated every month.
Qualifying the Thai line
- Capability audit — legal registration, capacity, equipment list, certifications.
- Sample and first article — dimensional report against drawing tolerances.
- Pilot batch — 5-10% of annual volume with full inspection.
- Process sign-off — control plan, AQL sampling, packaging spec.
- Ramp — step volume up over two or three cycles.
Governance
Hold both suppliers to the same scorecard: on-time delivery, defect rate in PPM, corrective-action closure time, and cost-change transparency. Review quarterly. Keep drawings, tooling ownership and IP assignments documented on both sides — see Contracts and IP Protection for Thai Manufacturing.
Common mistakes
- Treating the second source as a paper exercise and never ordering from it.
- Splitting volume so thin that neither supplier earns priority.
- Different specifications at each origin, making parts non-interchangeable.
Related: Supply Chain Resilience for Developed Markets, Capacity Planning with Thai Factories.
Frequently Asked Questions
What volume justifies a second source in Thailand?
Once a SKU family exceeds roughly one full container per quarter, a qualified Thai second source usually pays for its qualification cost within a year.
Will splitting volume raise my unit price?
Slightly at first. The offset is pricing leverage and continuity; most buyers recover the difference within two negotiation cycles.
Who owns the tooling if I dual source?
You should. Insist on written tooling ownership and the right to transfer tools between suppliers.
How do I keep parts interchangeable?
One controlled drawing set, one revision authority, and first article inspection at each origin before production release.