Turnkey vs Consignment PCB Assembly: Which Model Fits Your Project

Turnkey moves procurement, incoming inspection, moisture-sensitive handling, and shortage management onto the assembler. You review a costed BOM, approve alternates, and receive finished boards. Consignment keeps procurement with you: your purchasing team buys parts, ships kits, and owns every shortage, wrong reel, and date-code problem that arrives at the line. Partial turnkey splits the BOM—typically you consign the critical or long-lead parts you control, and the assembler sources passives and commodity parts.

The hidden variable is engineering time. A 150-line BOM means 150 sourcing decisions, availability checks, and package verifications. Under consignment that work lands on your team, and kitting errors (a mislabeled reel, a 90%-depleted feeder reel counted as full) become your production delays. Under turnkey the assembler absorbs it—priced into the quote, but executed by people who do it daily.

Consignment looks cheaper on paper because the assembly quote contains no component markup. The comparison is honest only if you count your own overhead: purchasing hours, incoming inspection, storage, kitting labor, freight for the kit, and the cost of line stoppage when one reel is short. For teams without an established purchasing operation, these costs routinely exceed a turnkey markup.

Turnkey pricing includes component cost plus handling margin, but assemblers buy through established distributor relationships and, for common passives, at volume prices an individual project cannot reach. Where turnkey genuinely costs more is on parts you can buy better than the assembler—custom modules, parts under an existing corporate pricing agreement, or allocation parts where you hold inventory. That is exactly the case partial turnkey exists for.

Turnkey lead time starts when the costed BOM is approved and runs procurement and fabrication in parallel—the assembler orders parts while boards are in fab. Consignment lead time starts when the complete, verified kit arrives at the assembler; any missing line restarts the clock. In stable supply conditions the difference is modest. During shortages, it widens: an assembler managing dozens of BOMs sees allocation problems early and proposes alternates as a routine service, while a consignment customer discovers the same problem at kit-check.

One caution on turnkey during allocation markets: approve alternates quickly. A turnkey program where every substitution waits a week for customer approval loses the model’s speed advantage. Agree on an alternate-approval process—pre-approved substitution rules for passives, engineering sign-off only for actives—before the first build.

Under turnkey, one party owns the entire chain of custody: authorized-channel sourcing, date codes, MSL handling, and storage. If a board fails from a counterfeit or mishandled component, accountability is unambiguous. Under consignment, a solder-joint failure is the assembler’s problem but a component failure is yours—and distinguishing the two after the fact consumes engineering time on both sides.

Regulated products complicate this in both directions. If your quality system requires purchasing through your own approved vendor list (AVL), consignment or partial turnkey may be mandatory for controlled line items. Conversely, if you lack the infrastructure for MSL baking logs and lot traceability, a turnkey assembler with documented processes strengthens your audit position rather than weakening it.

Choose turnkey when your team is small, the BOM is mostly catalog parts, and speed matters more than squeezing component margin—typical for prototypes, NPI builds, and small-batch production. Choose consignment when you have real purchasing infrastructure, pricing agreements the assembler cannot match, or AVL obligations that force it. Choose partial turnkey when a handful of lines are special (custom, allocated, or contractually sourced) and everything else is commodity—consign the few, turnkey the rest.

Whichever model you choose, put it in the RFQ explicitly, line item by line item for partial turnkey. At MOZPCB, turnkey requests get a costed BOM with flagged risks and proposed alternates before production release, and consigned kits get checked against the BOM at intake—both exist to surface the shortage before it stops the line, not after.