In a turnkey arrangement, the supplier purchases the agreed materials as part of the assembly scope. In a consigned arrangement, the customer supplies specified materials. Mixed sourcing divides that responsibility by item. The useful decision is the actual responsibility matrix, not the label alone.
Compare the ownership boundaries
| Decision | Turnkey scope | Consigned scope | Mixed scope |
|---|---|---|---|
| Purchasing | Supplier buys the agreed items | Customer provides the agreed items | Owner assigned to each item or group |
| Material readiness | Procurement status must be visible | Received kits must match the build | Both readiness paths must align |
| Shortages | Escalation and alternatives need approval rules | Customer replenishment or other action must be agreed | Define the decision owner for each shortage |
| Unused stock | Ownership and commitments require agreement | Return, storage and reconciliation require agreement | Maintain separate ownership records |
When turnkey simplifies the coordination
Turnkey can place several purchasing tasks inside one quoted scope, but it does not eliminate engineering responsibility. Release complete part numbers and define approved alternatives. Ask when purchasing is authorized, which commitments cannot be cancelled and how changes are approved. Confirm which materials are excluded from the turnkey offer.
When customer-supplied materials matter
A customer may already own inventory, have a required source or control a specialized item. In that case, define the receiving check, packaging, identification, quantity reconciliation and handling information. Ask what constitutes a complete kit and how damaged, incorrect or missing items affect the proposed build date.
Sending the exact theoretical quantity is not automatically the same as supplying an agreed production kit. Discuss handling allowance, packaging format and spare requirements for the actual process. Do not assume a universal attrition percentage; obtain and approve the proposed basis for the project.
Make mixed sourcing explicit in the BOM
Add a material-owner field and separate it from the approved manufacturer or source. A part can have one approved manufacturer while the purchasing owner changes between programs. Keep the design identity stable and record the commercial responsibility independently.
A practical mixed-sourcing example
Suppose the customer provides a programmed module while the assembler purchases the remaining components and bare boards. The plan should say who confirms module revision, receiving condition and quantity; who investigates a module failure during test; and whether replacement modules are needed before remaining units can ship. “Customer supplies the module” does not settle those questions by itself.
Review the turnkey assembly scope and component-sourcing requirements. Include the completed ownership matrix with the RFQ package, then compare the total commitment using the quotation checklist.
Turn the checklist into a project inquiry
Share the product stage, requested deliverable, quantity and unresolved decisions. Start with the files you have and identify what still needs review.