Quick answer
Compare turnkey and consigned PCB assembly on cost, lead time, component risk and sourcing responsibility, with a practical decision checklist.
The Three Sourcing Models
Most articles present this as a binary choice. In practice there are three, and the third is the one experienced buyers use most often.
For a project-specific sourcing decision, compare component sourcing with turnkey PCBA before requesting a quote.
- 01Full turnkey
You send Gerber files, BOM and Pick & Place. The manufacturer sources every component, fabricates the board, assembles, tests and ships. One purchase order, one point of accountability.
- 02Consigned
You buy all components and ship them to the manufacturer, who assembles only. You keep full control of sourcing — and full responsibility for what arrives.
- 03Partial turnkey
You supply the parts where you have an advantage — long-lead ICs already on order, allocated parts, or something with a contract price — and the manufacturer sources the rest.
It lets you keep control where control actually matters — usually a handful of expensive or allocated parts — while handing off the hundred passive components that are not worth your procurement time.
Comparison Across What Actually Matters
| Full Turnkey | Consigned | Partial Turnkey | |
|---|---|---|---|
| You provide | Gerber, BOM, Pick & Place | Files + all components | Files + selected components |
| Sourcing effort | None | Entirely yours | Split |
| Unit cost | Slightly higher (sourcing margin) | Lower if your pricing is good | In between |
| Lead time | Includes sourcing time | Fast once parts arrive | Gated by your parts |
| Shortage risk | Alternate sourcing and approval terms are agreed in advance | Yours | Shared |
| Counterfeit risk | Subject to the agreed sourcing and verification process | Yours to verify | Split |
| Attrition (spare parts) | Handled by manufacturer | You must ship extra | For your parts |
| Who is accountable for a bad joint on a bad part | Manufacturer | Disputed — needs agreement upfront | Depends on part origin |
| Best when | You want working boards delivered | You hold stock or have contract pricing | A few parts are critical or allocated |
The Attrition Trap in Consigned Assembly
This is the single most common way a consigned order stalls, and it is rarely explained clearly before it happens.
Automated placement consumes more components than your BOM quantity. Parts are lost in feeder setup, at reel splices, in first-article checks, and to the occasional misplacement. If you ship exactly the BOM quantity, the line will run short — and the whole job stops until you can air-freight more of a part that may now be out of stock.
Plan spare quantities with the assembler after reviewing feeder setup, package mix, expected attrition and the cost of a line stoppage. Small passives and expensive ICs may need different overage rules.
- Ship components in original manufacturer packaging where possible — reels and trays feed automatically, loose parts may need hand placement.
- Include a packing list that matches your BOM line for line, using the same reference designators.
- Confirm moisture-sensitive devices (MSD) are correctly bagged with desiccant — improperly stored parts can delaminate during reflow.
- Factor in shipping time and customs clearance — this is often the hidden lead-time cost of consigned.
Who Carries the Risk — The Question to Settle First
Cost differences between the models are usually modest. Risk ownership is where the real money is, and it only becomes visible when something goes wrong.
- A part is obsolete or unavailable mid-run. Under turnkey, the sourcing plan defines how an alternate is proposed and approved. Under consigned, production waits for you.
- A component turns out to be counterfeit or out of spec. Turnkey sourcing follows the agreed source, verification and traceability requirements. With consigned parts from an open-market source, verification responsibility sits with you.
- Yield loss traced to a marginal component. Under turnkey this is clearly the manufacturer's to resolve. Under consigned it needs to be agreed in advance, or it becomes a dispute.
- The BOM has an error. Turnkey providers usually catch this during BOM review before purchasing; under consigned the wrong parts may already be bought and shipped.
Whichever model you pick, agree upfront on who pays when a consigned part is faulty, and what happens if quantities run short. A short email on this is worth more than a long contract on everything else.
Lead Time: Turnkey Is Not Automatically Slower
The usual claim is that consigned is faster because sourcing is already done. That is true only if your parts are genuinely in hand.
| Service type | Standard | Expedited |
|---|---|---|
| Prototype assembly | After file/BOM review | Expedited, if confirmed |
| Small batch / low volume | After file/BOM review | Expedited, if confirmed |
| Mass production | After production planning | Subject to BOM availability |
Under consigned, the clock starts when your parts physically arrive — so international shipping and customs are part of your lead time even though they are invisible on the quote. Under turnkey, sourcing runs in parallel with board fabrication, which often closes most of the gap.
How to Choose: A Short Checklist
Work down this list. The first clear answer usually decides it.
- 1Do you already hold the inventory? If yes, consigned or partial makes sense — you have already paid.
- 2Do you have contract pricing materially better than a manufacturer can get? If yes, consign those specific parts.
- 3Is any part allocated, long-lead, or on order under your account? Consign that part; let the manufacturer source the rest — this is partial turnkey.
- 4Do you have a procurement function with time to manage a BOM? If not, turnkey removes work you are not staffed for.
- 5Is this your first production run with a new manufacturer? Turnkey concentrates accountability in one place, which is worth a lot when you are still building trust.
- 6Is the schedule tight and the BOM long? Turnkey lets sourcing run in parallel with fabrication instead of in series.
For most first-time and small-to-mid volume buyers, full turnkey is the lower-total-cost choice once you count your own procurement hours and the cost of a stalled line. Move to partial turnkey when you have specific parts worth controlling.
FAQ
Questions engineers ask before release
Is consigned PCB assembly always cheaper?+
Not once you count everything. The unit price is usually lower because there is no sourcing margin, but you absorb procurement labour, shipping, customs, attrition stock, and the cost of any delay caused by a missing part. Consigned is genuinely cheaper when you already hold inventory or have contract pricing a manufacturer cannot match.
What is partial turnkey assembly?+
You supply some components — typically long-lead, allocated, or contract-priced parts — and the manufacturer sources the remainder. It is common for buyers who want control over a few critical parts without managing an entire BOM.
How many spare components should I ship for consigned assembly?+
Plan on roughly 3–5% extra for small passives such as 0402, 0201 and 01005, plus a few spare units of expensive ICs. Automated placement consumes parts in feeder setup, reel splices and first-article checks, and running short mid-job stops the line.
Who is responsible if a consigned component is faulty?+
Normally the customer, since the manufacturer did not select or verify the part. This is exactly why it should be agreed in writing before the order — including what happens to yield loss caused by a marginal consigned component.
Can I switch from consigned to turnkey later?+
Yes, and many customers do once volumes grow and managing the BOM stops being worth the time. The transition is straightforward provided your BOM is clean and specifies manufacturer part numbers rather than generic descriptions.
Do I still get component traceability with turnkey?+
Yes. Components are sourced through certified distributors, pass incoming inspection (IQC), and MES traceability records run from component level through to panel level, so any board can be traced back to its material lot.
Reference points
Sources and verification starting points
External standards and industry references help frame the decision. Confirm current supplier evidence and project-specific requirements before release.