Consigned PCB assembly lets you supply components to an assembly manufacturer, which then builds your boards and performs the inspection and testing you agree in the quotation. If you supply only selected chips and ask the manufacturer to buy the remaining parts, request partial turnkey PCB assembly.
This arrangement can make sense when you already hold an MCU, memory IC or custom component. However, owning the chips does not automatically make the order cheaper or faster. The assembler still needs an acceptable, complete material kit and a clear build specification.
Before shipping parts, settle three practical questions: which BOM lines each party supplies, how many usable parts the build needs, and what event starts the quoted assembly lead time.
Consigned PCB Assembly Vs Turnkey: Which Model Fits?
The main difference concerns material sourcing. PCB fabrication, programming and testing still need an explicit scope in every model.
| Assembly Model | Who Supplies Components? | When It May Fit |
|---|---|---|
| Full turnkey | The manufacturer sources the agreed BOM | You want one supplier to coordinate material purchasing and assembly |
| Consigned assembly | You supply the agreed component kit | You already own the materials or must use a controlled purchasing channel |
| Partial turnkey | You supply selected parts; the manufacturer sources the rest | You hold critical chips but want the factory to buy standard components |
For example, an equipment manufacturer may supply its programmed processor and approved memory, while the assembler purchases resistors, capacitors and connectors. That is a mixed sourcing arrangement, not a reason to send two conflicting BOMs.
Use one controlled BOM with a supply-owner column. For the broader sourcing model, see the turnkey PCB assembly overview.
The terminology alone does not define who supplies the bare PCB. State that separately, along with any stencil, programming or final-test requirements.
Can I Supply Only The Expensive Or Hard-To-Find Chips?
Yes, where the manufacturer accepts a partial turnkey arrangement. Identify the exact parts you will supply and obtain agreement before placing either purchasing order.
This can preserve an existing allocation or use stock you already own. Nevertheless, compare the whole build: a missing low-cost connector can delay production just as effectively as a missing processor.
A proposed sourcing worksheet might look like this:
| BOM Group | Supply Owner | Information Needed Before Release |
|---|---|---|
| MCU or processor | Customer | Full ordering code, quantity, packaging and programming status |
| Memory ICs | Customer | Exact variant, quantity and lot information |
| Resistors and capacitors | Assembler | Approved values, ratings, packages and substitution rules |
| Connectors | Assembler | Exact part number or approved alternatives |
| Bare PCBs | Agreed separately | Released fabrication data and accepted panel arrangement |
Keep the full manufacturer ordering code. A base family name may omit the memory size, temperature grade or package option.
Also specify do-not-populate positions. The receiving team should not interpret a deliberate omission as a shortage or assume that an unexpected extra part belongs on the board.
Use the PCB BOM guidance to make supply ownership part of the released build data.
Is Consigned PCB Assembly Actually Cheaper?
It can be, but a lower assembly invoice does not necessarily mean a lower total project cost.
Compare both options using the same build quantity, component specifications and test scope. For customer-supplied material, include purchasing effort, inbound shipping, receiving or kitting charges, any agreed conditioning, and the cost of resolving shortages.
The following arithmetic is illustrative, not a quotation:
| Cost Item For 100 Boards | Full Turnkey | Customer-Supplied Components |
|---|---|---|
| Components for the agreed material kit | $2,000 | $1,850 |
| Assembly and agreed testing | $800 | $800 |
| Additional inbound parts shipment | Included in this example | $90 |
| Separate receiving/kitting charge | Included in this example | $80 |
| Comparison total | $2,800 | $2,820 |
In this example, a $150 component saving does not offset $170 of added shipment and handling costs. Other suppliers may bundle charges differently, and your existing inventory may change the comparison.
If you already paid for the chips, distinguish the additional cash needed now from the total material cost of the project. Treating existing stock as free can distort a comparison between repeat-order sourcing options.
Ask the supplier to identify each charge in the PCB assembly quotation, including any assumptions about material completeness.
How Many Extra Components Should I Send?
Ask for the assembler’s part-specific quantity requirements before dispatch. Do not apply one percentage to every component.
For each BOM line, calculate:
Required shipment = planned placement quantity + agreed setup/process allowance + any separately agreed reserve.
Planned placement quantity means board quantity multiplied by placements per board. If 100 boards each use two identical ICs, the build requires 200 placements before any agreed extra quantity.
Extra-part policies differ by package, value and process. For example, Screaming Circuits’ published attrition requirements distinguish component categories and allow different treatment for high-value parts. Those are that supplier’s conditions, not a universal allowance or a statement of Haode’s requirements.
What If I Have Exactly Enough MCUs?
Tell the assembler before booking production. Ask whether it can accept an exact-quantity supply and what happens if receiving rejects a part or a component needs replacement.
An agreement to accept 100 MCUs does not by itself guarantee shipment of 100 working boards. The production plan still needs a disposition for shortages, defective material and assembly failures.
Keep any extra material identifiable. An agreed setup allowance does not mean the factory will necessarily consume all of it; reconcile actual usage after the order.
Can I Send Cut Tape, Opened Reels Or Parts Directly From A Distributor?
Possibly, but obtain the receiving and packaging instructions first.
Cut tape can suit some builds, while other equipment or quantities may require additional handling or re-reeling. Ask about accepted tape lengths, carrier condition, part orientation, labels and any associated charge. Do not assume that loose parts and a labelled reel create the same assembly workload.
For opened moisture-sensitive devices, preserve the available handling records and original labels. Texas Instruments’ shelf-life guidance explains why storage conditions and moisture-sensitive packaging matter after customer delivery.
The assembler should review the device requirements and exposure history. A newly closed bag alone does not resolve an unknown history. Discuss any necessary handling through the moisture sensitivity level review before the scheduled build.
Direct distributor delivery may simplify shipping, but first confirm the receiving address, project identifier and packing-list requirements. Tell the factory what will arrive and which order it belongs to. Otherwise, an authentic, correctly packed reel can still become an unidentified delivery waiting for clarification.
When Does The Assembly Lead Time Start?
For consigned PCB assembly, ask the supplier to define the schedule trigger in writing. “Five-day assembly” could refer to a period after accepted material receipt and engineering release, rather than five days after payment or courier delivery.
Distinguish these milestones:
- Delivered: The courier has brought the shipment to the factory.
- Received and checked: The factory has reconciled identity, quantity and condition.
- Ready for production: Required materials, files and approvals are available.
- Scheduled: The factory has assigned the necessary production capacity.
For a mixed-source order, track both material streams. Your chips arriving early does not help if a factory-sourced connector remains unavailable.
Similarly, a kit can be physically complete while a firmware file, polarity clarification or test instruction still blocks release. Ask for an open-issue list with an owner and next action for each item.
If one part will arrive late, discuss a revised build plan before authorizing partial assembly. Installing it afterward may need additional handling, rework or inspection, and may not suit the package or process.
Who Checks Customer-Supplied Parts And Handles Failures?
Define receiving inspection separately from electrical testing. A count and label check does not establish every device’s electrical performance or authenticate an entire shipment.
Agree what the incoming review includes, which discrepancies trigger a hold, and who decides the next action. For example, a mismatched ordering suffix should prompt clarification before the factory loads the part.
If a completed board fails, investigate the evidence before attributing the failure to either the material or assembly. Useful evidence may include component identity, inspection results, test measurements and repair findings.
Ask the quotation to explain how the teams handle:
- A shortage or mismatch at receiving.
- A suspected defective customer-supplied component.
- An identified assembly defect.
- A failure whose cause remains unresolved.
These are coordination questions for the order. Responsibility for replacement costs and rework should follow the agreed terms and established facts, not an assumption based only on who purchased the component.
For parts the factory buys, retain clear component-sourcing requirements, including approval rules for alternatives.
Does Consigned PCB Assembly Include Programming And Testing?
Only when the quotation includes them. Supplying your own components determines the material arrangement; it does not define the finished-board acceptance criteria.
A useful scope identifies programming, inspection, powered testing, any external loads, and the required result records. Do not substitute “100% tested” for a description of those checks.
For programmed ICs, tell the assembler whether you will supply them blank or preprogrammed. If device-specific identifiers matter, explain how the process allocates and verifies them.
For PCBA functional testing, provide the intended behavior and acceptance requirements. A simple startup check and a test of every output under load represent different work, even if both use the term functional test.
If you do not yet have a test procedure, request a separate estimate for developing one. Make the required delivery condition clear before comparing prices.
What Happens To Unused Components After Production?
Agree whether the factory returns leftovers, holds them for another order or requests instructions. Confirm any storage or return-shipping charges.
Ask for a closing balance that separates:
Received quantity = fitted quantity + documented process losses + rejected quantity + returned quantity + retained balance.
Use mutually exclusive categories and investigate discrepancies. If the order remains open, identify material in work in progress separately rather than counting it twice.
For subsequent builds, retained stock still needs an available balance, identifiable lot and acceptable storage condition. Define the necessary PCBA traceability records when arranging storage.
Do not assume the remaining quantity shown after one order is automatically enough for the next. Recalculate placements and any agreed allowances against the new build quantity.
Requesting A Consigned PCB Assembly Quote
Send the manufacturer a complete build package and identify the customer-supplied BOM lines clearly. Include quantities, packaging format, expected arrival dates, bare-board supply responsibility and programming/test requirements.
You can adapt this request:
Please quote assembly for our attached design and BOM. We will supply the BOM lines marked “Customer”; please quote the remaining approved materials separately. Confirm required quantities, accepted packaging, receiving charges and the event that starts assembly lead time. Please also identify programming and test scope, shortage handling, and the return or storage arrangement for unused parts.
For a Haode PCBA enquiry, use these details to request confirmation that the proposed material split and build requirements suit the project before shipping stock.
Consigned PCB assembly works best when both teams can answer three questions without guessing: what material will arrive, when the order becomes ready to build, and what evidence makes the finished boards acceptable.
