Choose the component supply model before comparing PCB assembly quotations. If you already hold critical ICs or have purchasing agreements with approved distributors, supplying those parts may make sense. If you want the assembly supplier to coordinate procurement, request a turnkey quotation.
The decision comes down to who can secure the correct components, deliver them on time and manage the remaining inventory. Partial turnkey PCB assembly is worth comparing when only part of the BOM needs to stay under your purchasing control.
Choose the Supply Model That Fits Your BOM
| Supply Model | Who Purchases Components? | When It Fits | Main Point to Confirm |
|---|---|---|---|
| Full turnkey | The supplier purchases the BOM components within the agreed scope. | You want coordinated procurement and assembly without managing individual component deliveries. | Approved sources, alternatives, purchasing quantities and excess stock. |
| Consigned assembly | You supply the components; the manufacturer handles the agreed assembly work. | You already own suitable inventory or must use your own purchasing channels. | Material condition, packaging, quantities and delivery to the assembly site. |
| Partial turnkey | You supply selected BOM lines; the supplier purchases the rest. | You hold critical or allocated parts but want the supplier to source standard components. | A clear purchasing owner for every BOM line. |
Confirm bare PCB supply separately. Consigning components does not necessarily mean supplying the bare boards, and an assembly-only quotation should not be compared directly with one that includes PCB fabrication.
When Turnkey PCB Assembly Makes Sense
Turnkey PCB assembly reduces the purchasing and delivery tasks your team must coordinate. It is useful when you do not already hold components and want one supplier to align material availability with PCB fabrication and assembly.
Before authorizing purchases, confirm unavailable parts, approved alternatives and any minimum purchasing quantities. A turnkey arrangement does not give the supplier permission to change manufacturer part numbers without the agreed approval.
Ask whether the quoted component cost covers only the build quantity or also includes full reels, minimum-order quantities and setup allowance. Identify who owns any paid-for surplus.
When Consigned or Partial Turnkey Assembly Is Better
Consigned PCB assembly can suit projects with existing inventory, customer-controlled devices or established distributor agreements. However, the parts must arrive in packaging and condition that the assembly supplier can use.
Confirm reel, cut-tape, tray or tube acceptance before shipping. Keep manufacturer labels and relevant handling information with the materials. Loose or unidentified parts can create additional checks and preparation work.
For example, if you already hold the required MCU and a custom connector, mark those two BOM lines as customer-supplied and request supplier sourcing for the remaining components. This lets you retain control over specific parts without taking on the entire purchasing workload.
Compare Total Cost, Not Just the Assembly Charge
A consigned quotation may look lower because component purchasing is outside its scope. Compare both options using the same board quantity, assembly requirements and testing coverage.
- Component purchasing: include the parts you buy yourself, minimum quantities and unused inventory.
- Material delivery: include freight, applicable import charges and any separate shipments.
- Preparation: ask about incoming checks, counting, repackaging or other agreed handling charges.
- Production: compare the same PCB, stencil, assembly, programming and testing scope.
Use the same basis when reviewing PCB assembly quotation costs. Existing inventory may reduce new spending, but it still has a value and needs to be tracked.
Agree on Shortages, Losses and Unused Parts
For customer-supplied materials, agree the required delivery quantity before dispatch. Do not assume the exact placement quantity is sufficient, or apply one blanket spare percentage to every component. Packaging, setup requirements and component value affect the allowance.
Put these points in writing:
- Receipt confirmation: how quantities, labels and visible packaging condition will be checked and discrepancies reported.
- Shortage handling: who supplies replacements and how missing parts affect the production schedule.
- Loss or damage: the agreed allowance, reporting process and responsibility for losses beyond it.
- Remaining stock: whether unused components will be returned or held for a later order, with quantities and ownership recorded.
Request a schedule based on material readiness, approved files and test preparation. A delivery date for customer-supplied parts is not the same as confirmation that the complete kit is ready for assembly.
Mark the Supply Split Before Requesting a Quote
Add a “Supply By” column to the BOM and mark each line as customer-supplied or supplier-purchased. For customer-supplied parts, include the available quantity, packaging and expected arrival date. Keep approved alternatives in a separate column.
Order & Project Support: When requesting PCB assembly services from Benchuang, send the marked BOM with your PCB files, assembly drawings, quantities and testing requirements. Identify any parts you already own so the sourcing scope can be reviewed without duplicate purchasing.
