1.1 What is Box Build?
Scope, role in manufacturing, and where it fits in the flow.
Box build—oftenbuild called final assembly or system integration—is where all the finished pieces come together into a working product. It’s the stage afterwhere PCBselectronics aremanufacturing solderedleaves the lab and harnesses are tested, where mechanical parts, wiring, firmware, and accessories are fitted, connected, and verified. This step carriesenters the responsibilitycustomer’s forhands. mechanicalIt fit,is the point where electrical performance, safetymechanical compliance,integrity, cosmetic finish, and correctregulatory labelingcompliance beforeall shipment.converge into a complete, working product. Because it’sthis is the last pointtouch before theshipment, customersuccess seeshere determines whether the product,entire boxeffort buildof blendsdesign, precision, variant control,sourcing, and disciplinedassembly checkstranslates tointo ensure everything worksquality and lookstrust rightin the first time.market.
1.1.1 Plain-English definition
Box build (a.k.a. final assembly or system integration) is where we take finished subassemblies—PCBA(s), harnesses, displays, fans, storage, power supplies, enclosures—and turn them into a working product. It’s the last mile: mechanical fit, wiring, firmware/config, functional/safety test, labels, and pack-out.
Think: everything after soldering the boards and before the shipping label.
1.1.2 What’s in scope vs out of scope
1.1.3 Where it sits in the factory flow
Materials → SMT/THT → Clean/Inspect → Programming (optional) → Conformal coat (optional) → Box Build → Test → Burn-In (if used) → Final QC → Pack & Ship
Handoffs into box build
- PCBA(s) (AOI/AXI done, function/ICT passed)
- Harnesses (tested, serialized)
- Enclosure (painted/plated, threads QC’d)
- Thermal parts (TIM pads/paste, heatsinks)
- Bought-outs (PSUs, fans, drives, displays)
- Docs (BOM, exploded view, torque chart, routing map, label set)
1.1.4 Levels of build (what “box” means today)
1.1.5 The Box Build “contract” (inputs & outputs)
Inputs you must have (Golden Data Pack + fixtures):
- Exploded views, step-by-step SWI with photos, routing diagram, torque map, adhesive/TIM notes, label map
- Test plan (limits, fixtures, scripts) and programming image
- Variant matrix (which options/labels/accessories per SKU)
- Acceptance criteria (cosmetics, gaps, flushness, wobble, noise)
Outputs you own:
- A powered unit that boots, passes test, and is safe
- Serialization (unit & subassemblies bound in MES)
- Regulatory & customer labels applied correctly
- Pack kit complete and documented
1.1.6 Decision gates (don’t build past a bad step)
- Kitting OK — all parts, correct variant, ESD-safe, torque tools in cal.
- Mech First Article — dry fit: standoffs heights, hole alignments, door/cover fit, gasket compression.
- Torque Audit — sample fasteners meet spec; threadlock/washer types correct.
- Cable Routing Check — clamps, bend radii, shield bonds, no pinch points.
- Power-On / Functional — passes scripted FCT; fans/LEDs/sensors behave.
- Safety Test — earth/hipot/leakage where required.
- Cosmetic & Label — gaps/flushness/finish; all marks/legal/regulatory in place.
- Pack Review — accessories, manuals, foam orientation, drop-test method.
Fail any gate → NG-QUAR the unit and fix before moving.
1.1.7 Tooling & controls that make BB smooth
- Torque drivers with programmed setpoints + bit ID; post the torque map.
- Locating fixtures: zero-point pins for chassis, display bezels, and PSU cages.
- Adhesive/TIM kits: pre-cut pads, measured syringes; one bead size chart.
- Label station: prints from MES only; no hand edits.
- ESD discipline: mats, straps, ionizers; metalwork bonded; safe power-up routine.
- Visual boards: routing photos, connector pin-1, gasket path, label diagrams.
1.1.8 Roles & handoffs (who does what)
1.1.9 Why box build matters (and common traps)
Why: it’s where fit, finish, and function meet. A great PCBA can still fail here from bent pins, crushed gaskets, wrong labels, or cables pressed against fans.
Traps → Smallest reliable fix
- Variant mix-ups → Scan SKU/Variant to unlock SWI, label set, and test.
- Stripped threads → Torque map + thread repair kits; start fasteners by hand.
- Fan/noise/thermals → Respect airflow arrows; TIM amount & placement; don’t block vents with harness.
- EMC regressions → Ensure 360° shield bonds, gasket continuity, paint scrape points where called.
- Cosmetic defects → Handle with gloves; use clean mats; inspect at bright, diffuse light.
1.1.10 Pocket checklist (start-of-lot)
- Kit & Variant match traveler; accessories present
- Fixtures & torque tools verified and in cal
- SWI/label/test programs loaded from MES by scan
- First Article: dry fit + torque + routing check signed
- Safety equipment (ESD, guards) in place