Box build assembly turns a working PCBA into a finished product or sub-system. The RFQ must include more than board files. Mechanical parts, cables, labels, fasteners, test steps, and packaging all affect cost, quality, and schedule.
Decision in brief: a PCBA RFQ can define the electronic assembly, while a box-build RFQ must define how the finished unit is assembled, tested, identified, packed, and released. Use the broader package when the supplier is responsible for any enclosure, cable, harness, fastening, final test, labeling, accessory, or shipment handoff. Do not treat it as a generic extension of board assembly.
Use the PCBA buyer decision center to keep the box-build scope connected to RFQ files, sourcing rules, test coverage, and traceability instead of treating final assembly as an isolated purchasing step.
Reference context: the IPC-D-326A information-requirements guide covers information needed to procure material and perform box build, assembly, system integration, inspection, test, burn-in, and delivery. It is a useful documentation framework—not a statement that every requirement in it applies to a product or that a supplier is certified. See the engineering editorial and evidence standards for source and attribution boundaries.
PCBA RFQ versus box-build RFQ
| Scope | Board-assembly RFQ | Box-build RFQ |
|---|---|---|
| Core inputs | PCB data, BOM, centroid, assembly drawing, test requirements. | All PCBA inputs plus enclosure/harness data, assembly sequence, labels, accessories, packaging, and final release rules. |
| Main risk if unclear | Incorrect material, assembly, or test assumptions. | Fit, cable routing, torque, cosmetic, firmware, packaging, and shipment assumptions remain unpriced or uncontrolled. |
| Release evidence | Assembly and board-test records appropriate to the agreed scope. | Defined final functional/visual checks, unit identification, accessory count, and packing/release record where required. |
Mechanical and assembly files
Share 2D drawings, controlled 3D files where available, exploded views, mechanical BOM, part list, torque requirements, adhesive or gasket notes, and critical dimensions. Specify the product revision that governs the build. If enclosure parts are customer-supplied, state incoming-inspection responsibility, cosmetic acceptance, and what happens when a supplied part does not fit or is damaged.
Cable and harness details
Cable routing can create reliability issues if bend radius, strain relief, connector locking, service loops, and connector orientation are undefined. Provide harness drawings, wire labels, connector keying, allowed routing path, and pull-test or continuity expectations where relevant. Do not assume a cable length in a drawing establishes a safe service loop or strain-relief method.
Functional test and configuration procedure
- Power-supply, load, and environmental conditions used for the test.
- Firmware image, configuration version, programming tool, and permitted recovery path.
- Communication interfaces, measured limits, safety indicators, and pass/fail logic.
- Unit, lot, or serial-number rules and the required report format.
Visual completion is not proof of product behavior. Define who supplies fixtures, loads, software, golden samples, and acceptance limits; state whether the procedure is engineering validation, production screening, or final release.
Packaging and shipment requirements
Packaging is part of product quality. Define ESD protection, moisture or foam protection where appropriate, carton size and weight limit, label placement, accessory-kit contents, transit-test expectations, and shipping method. For export programs, align invoice, HS code, battery declarations, and destination requirements early. Product-specific transport validation is needed when the application requires it; a generic carton description is not validation evidence.
RFQ release checklist
- Released mechanical, electrical, firmware, and packaging revisions are identified together.
- Customer-supplied parts, approved substitutes, and incoming-inspection ownership are stated.
- Assembly sequence, torque/adhesive controls, cable routing, and rework limits are clear.
- Final-test limits, unit identification, cosmetic acceptance, and shipment release record are agreed.
Practical takeaway
A strong box-build RFQ describes the complete product handoff from incoming parts to final shipment. PCBA PARTNER can review PCB assembly, cable integration, enclosure assembly, functional test, labeling, and packaging through our Box Build Assembly service; the final scope and acceptance evidence must be confirmed for the specific program.