What belongs in a PCB assembly cost breakdown?
A useful quotation identifies what is being delivered, which assumptions affect price and which charges repeat. Fabrication, purchased components, assembly labor and product testing are different work packages. A consigned quote may exclude components; a turnkey quote may include them. Neither is cheaper merely because its displayed assembly price is lower.
| Cost category | Ask the supplier to state | Question before comparing |
|---|---|---|
| PCB fabrication | Construction, material, finish, panel format and board quantity | Are both quotes for the same bare-board specification? |
| Purchased components | Exact MPNs, source restrictions, approved alternates and quote validity | Are minimum buys, freight and unused parts included or separate? |
| Setup and tooling | Stencil, program preparation, fixtures and engineering scope | What may be reused, and what triggers another charge? |
| Assembly | Sides, package mix, SMT/THT route and batch quantity | Does the price cover all fitted positions and agreed operations? |
| Programming and testing | Firmware, procedure, fixture, coverage and records | Is the same acceptance plan priced in both quotes? |
| Packaging and logistics | Labels, protective packaging, destination and delivery terms | Which shipping, import or other charges remain outside the quote? |
| Unused inventory | Minimum-buy excess, attrition allowance, ownership and reuse | Who pays for stock that may not be used in the next revision? |
Why low-volume assembly cost is not only a unit price
For a small batch, setup and tooling are spread over fewer boards. Buying a larger quantity can reduce the quoted unit price while increasing the cash committed to components and boards. If the design changes or demand does not arrive, the additional stock can become an exposure rather than a saving.
Ask for separate quotations for the quantities you can genuinely use. Treat a forecast as planning information, not a purchase commitment. Distinguish the first order from a repeat order using unchanged, reusable tooling. A supplier should explain reuse conditions instead of promising that every future setup charge disappears.
| Decision | Possible benefit to compare | Exposure to keep visible |
|---|---|---|
| Combine demand into a larger batch | Fewer changeovers and different purchasing brackets | Cash, storage and obsolescence if demand or revision changes |
| Retain tools or unused parts | Potential reuse in a compatible repeat build | Ownership, condition, retention period and change compatibility |
| Use customer-supplied parts | Buyer controls an existing material source | Kit shortages, handling, counting and attrition responsibility |
| Add a fixture | A more repeatable agreed test procedure | Development, validation, maintenance and quantity justification |
Use a same-scope quotation comparison worksheet
Start with one released revision and list the inclusions, exclusions and unresolved assumptions. Compare order totals on the same currency, quantity and delivery basis. Do not compare a parts-excluded quote with a complete build, or a quote without functional testing with one that includes a validated test procedure.
- State the product and file revision, fit/DNP population and sourcing model.
- List setup and tooling separately from per-batch fabrication, parts and assembly.
- Match programming, inspection, test and record requirements.
- Record material-validity limits, minimum buys and excess ownership.
- Name delivery terms, destination, payment assumptions and excluded charges.
- Ask which costs or lead times change when quantity or revision changes.
Download the blank quotation-comparison worksheet (.txt). It contains no example prices, customer data or assumed production result.
From price comparison to an order decision
- 01
Freeze scope
Name one revision, quantity, sourcing model and acceptance plan.
- 02
Separate charges
Record recurring costs, one-time charges and exclusions.
- 03
Resolve differences
Ask suppliers to explain missing operations and material assumptions.
- 04
Approve the order
Accept the agreed scope, stock exposure and release conditions.
Use the PCBA quotation file checklist to reduce data ambiguity. For recurring orders, the high-mix guide covers configuration and retained-stock controls; it is a separate decision from the cost comparison here.
Questions about prototype setup and turnkey quotations
Why can prototype PCB assembly setup cost be significant?
Program preparation, stencil or fixture work and engineering review can be needed even for a small batch. Ask which charges are one-time, revision-dependent or repeated at each changeover. The actual amount requires a project quotation.
Does a lower unit price always mean a lower small-batch cost?
No. Compare the complete order total, one-time charges, minimum-buy stock, testing and exclusions on the same basis. A larger order can have a lower quoted unit price but commit more cash to material you may not use.
How should I compare turnkey PCB assembly quotations?
Use the same released PCB and BOM revision, quantity, approved sourcing rules, inspection and test scope, delivery basis and unused-stock instructions. Ask for differences to be stated before choosing on price.
Request a comparable small-batch quotation
Describe your batch size, expected reorder pattern, sourcing model and the cost items you need separated. Share a non-confidential brief first; this worksheet is not an instant quotation.
Review my quotation scope