Custom electronics and PCB assembly: MOQ, tooling, lead time and landed cost
Confidence 4/5 Established practice
Electronics splits into two problems that get confused with each other: making the bare board, and assembling the components onto it. A PCB fab is a commodity service with essentially no minimum, while assembly depends on component availability — and component availability, not assembly labour, is what actually determines whether an electronics project ships on time.
Quick answers
| Minimum order quantity | Bare PCBs: from 5 pieces. PCB assembly: from 1–10 boards for prototypes, with a practical floor around 50–100 for a cost-effective run because of stencil, programming and component reeling. |
| Lead time | Bare PCB: 5–10 days. Assembly: 7–20 days on top. Long-lead components can add 8–20 weeks and are the dominant risk in this category. |
| Tooling | PCB fabrication has no tool. Assembly needs a stencil (USD 50–200) and programming and test fixtures (USD 100–1,000) which are one-off per design. |
| Unit cost | Bare 2-layer prototype boards: a few dollars each in small quantity. Assembled boards are dominated by component cost, and quoting without a firm BOM and a component availability check is guesswork. |
| HS classification | Bare printed circuit boards fall under 8534.00. Assembled boards generally follow the function of the finished device rather than a single "PCB" heading, which is a common and costly classification mistake. |
| Certification | FCC and CE are market-access requirements for most electronic devices and involve EMC testing, not just a certificate from the factory. RoHS and REACH apply to materials. For anything with a radio, intentional-radiator approval is a separate and longer process. |
| Duty | US Section 301 tariffs have applied to many Chinese electronics categories at rates that have changed repeatedly, so this is the category where a remembered duty rate is least trustworthy. |
Common mistakes
- Quoting from a BOM without checking component availability and lifecycle status.
- Assuming the factory will handle FCC or CE. It usually will not; that is a separate test house process.
- Designing in a single-source or end-of-life component.
- Skipping functional testing definition, then receiving boards nobody has verified.
- Treating the bare board and the assembly as one quote from one supplier when they are usually two.
Detailed answers
Sources
- PCB fabrication and assembly service terms — Published fab-house and assembly service guidance
- Printed circuit boards under HS 8534 — World Customs Organization HS nomenclature
- Section 301 tariff actions on Chinese goods — US Trade Representative
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