- Box build is full assembly of a finished product: PCBA, enclosure, cables, displays, power supply, final test and a packaged unit ready to ship.
- Vietnam has electronics clusters in the north (Bac Ninh, Bac Giang, Hai Phong, Hanoi) and the south (Ho Chi Minh City, Binh Duong, Dong Nai), plus trade agreements with the EU, UK, Japan and Korea.
- Indicative full box-build lead time is 4 to 8 weeks for 500 to 10,000 units after sample approval, but every figure must be confirmed by factory quotes.
- A complete RFQ (BOM, drawings, test spec, volume) is what separates a two-week quoting round from a two-month one.
Box build assembly is where an electronics product stops being a set of parts and becomes something a customer can unpack and plug in. For an OEM, it is also the stage where the most suppliers, drawings and test decisions come together, which is why choosing where to do it matters more than choosing where to buy a bare board.
Vietnam has become a serious option for this work. Large brands moved phone, laptop and networking production there over the past decade, and a layer of mid-sized EMS and box-build factories has grown around them. Those factories now take on programs for hardware companies from the US, EU, Japan, Korea and Singapore that want a second source outside China or a primary source closer to their trade agreements.
This guide explains what box build covers, what Vietnamese factories typically handle, how a project usually runs from RFQ to shipment and which numbers to treat as indicative only. It is written for the engineer or buyer who has to put a real product into production, not for someone comparing slogans.
What box build assembly actually covers
Box build (also called systems integration or full product assembly) is the complete assembly of a finished product. It sits one step beyond bare PCBA and one step before consumer fulfilment. A typical box-build scope includes:
- PCBA, either built in-house by the same factory or consigned by the OEM
- Enclosure: plastic injection-molded housings or sheet-metal chassis
- Internal cables and wire harnesses
- Displays, touch panels, speakers, antennas and sensors
- Power supply, batteries or battery packs
- Firmware loading, calibration and final functional test
- Labelling, retail packaging, inserts and manuals, ready to ship
The practical question for a buyer is how much of that chain you want one factory to own. The table below shows the usual levels.
| Build level | What the factory delivers | What the OEM still manages |
|---|---|---|
| Bare PCBA | Populated, tested boards | Enclosure, cables, final assembly, test, packing |
| PCBA plus sub-assembly | Boards with cables, heatsinks or small modules fitted | Enclosure sourcing, final assembly, final test |
| Partial box build | Assembled unit using OEM-supplied enclosure or parts | Some component sourcing, packaging, compliance files |
| Full box build | Finished, tested, labelled and packed product | Design ownership, certification, logistics choices |
Moving up the table reduces the number of hand-offs between suppliers, which is where many quality problems start. It also concentrates more of your product knowledge in one factory, so the choice of partner and the NDA matter more.
Why OEMs look at Vietnam for box build
Vietnam is one of the main China+1 destinations for electronics. Samsung, Foxconn, Pegatron and Luxshare run large plants in the north, and their presence has pulled in component distributors, plastics and metal shops and a workforce used to electronics assembly. The two main clusters are:
- North: Bac Ninh, Bac Giang, Hai Phong and the Hanoi area, close to the large brand plants and the Hai Phong port
- South: Ho Chi Minh City, Binh Duong and Dong Nai, with a denser base of mid-sized and privately owned factories
Trade access is the other reason. Vietnam has free-trade agreements with the EU (EVFTA), the UK (UKVFTA), Japan and Korea, and is a member of CPTPP and RCEP. For EU and UK buyers in particular, preferential duty can change the landed cost comparison.
Two cautions belong in every business case. First, US tariff rates change, so check the rate for your HS code at the time of import rather than relying on a figure from last year. Second, rules of origin matter for any product with significant Chinese content. Whether a unit counts as Vietnamese origin depends on substantial transformation or the specific rules of the relevant agreement, not on the address of the last assembly step.
What Vietnamese box-build factories typically handle
Capabilities vary widely between factories, so treat the lists below as what the stronger box-build suppliers commonly offer, not as a guarantee for any single one. Our box build assembly in Vietnam page summarises the same scope for quick reference.
Electronics and PCBA
- SMT and through-hole PCBA, commonly to IPC-A-610 Class 2 for commercial and industrial products
- Conformal coating and potting for boards exposed to humidity, vibration or dust
- AOI after reflow and X-ray on BGA or bottom-terminated parts at factories that have it
Enclosures and mechanical fit
- Plastic injection or sheet-metal enclosures, either made in-house or through regular sub-suppliers
- Mechanical fit verification on pilot units before scale-up, which catches boss, clip and connector alignment problems early
Cables, displays and sub-assemblies
- Custom cable assemblies with crimp and connector matching
- Wire harness routing and labelling inside the enclosure
- LCD, OLED and touch panel integration
- Speaker, antenna and sensor sub-assembly
Test, compliance and shipping
- Functional test fixtures designed per product
- Burn-in for power and thermal validation
- Calibration data logging with serial number tracking
- FCC, CE and RoHS pre-compliance support (formal certification is still done through an accredited lab and remains the OEM’s responsibility)
- Retail packaging, inserts and manuals, with country-of-origin marking
- Freight to the US, EU, Japan and Australia, plus HS code classification and customs documents
Products that fit this model
The categories that most often go to Vietnamese box-build lines are products with moderate mechanical complexity and a clear functional test:
- IoT gateways, smart-home hubs and Wi-Fi mesh nodes
- Industrial controllers, PLC enclosures and edge gateways
- Consumer audio: speakers, soundbars and headphones
- Battery-powered devices such as trackers, wearables and handheld scanners
- Display modules for digital signage, kiosks and POS terminals
- Medical-adjacent wellness and fitness devices that are not FDA-regulated
Regulated medical devices, aerospace and defence products need factories with specific quality systems (ISO 13485 for medical, for example) and should be screened for that from the first conversation. The same applies to automotive electronics, where IATF 16949 is the normal expectation.
Your product stage changes the conversation
Factories respond differently depending on how mature your design is. Be honest about the stage in your RFQ.
| Product stage | What to send | What to expect from factories |
|---|---|---|
| Concept | Requirements, sketches, target cost and volume | Few will quote; some offer DFM input at a fee |
| Working prototype | Prototype BOM, schematics, rough enclosure CAD | Budgetary quote, list of DFM changes before tooling |
| Pre-production, DFM done | Released BOM, Gerbers, STEP files, test spec | Firm quote, tooling plan, sample schedule |
| In production elsewhere | Full production package, current yield and test data | Transfer quote, often with a pilot lot to prove equivalence |
A transfer from an existing supplier is usually the fastest route to a firm price, because the data package is complete. A concept-stage project is better served by a design house first.
How a box-build project typically runs
Most projects follow the same five steps, whatever the product.
- Brief and BOM review. The factory checks the BOM for obsolete, long-lead or single-source parts and reviews drawings for manufacturability.
- Factory shortlist. The OEM narrows to two or three factories whose equipment, certifications and volume range fit.
- Quote and sample. Quotes arrive on different Incoterms, commonly DDP or FOB. Convert them to the same basis before comparing, then approve a first-article sample.
- Production. Typical controls are in-line inspection, AOI on boards, final unit test on every unit and regular WIP reports to the buyer.
- Pack and ship. Units are packed to your spec, marked with country of origin and shipped with the customs documents your forwarder needs.
Indicative lead times and volumes
The figures below are commonly quoted ranges, not commitments. Every one of them has to be confirmed by the factory quotes you receive, and component availability can move them significantly.
| Item | Indicative range |
|---|---|
| First-article or sample build | 2 to 4 weeks after all parts are in hand |
| Full box-build production, 500 to 10,000 units | 4 to 8 weeks after sample approval |
| Long-lead components (some MCUs, displays, custom parts) | Can add 8 to 20+ weeks |
| Minimum order for prototype-to-production runs | From about 100 units |
| Large programs | 50,000+ units per month at bigger factories |
Long-lead parts are the most common reason a schedule slips. If your BOM contains parts with long factory lead times, consider buying them early or approving alternates before the RFQ goes out.
Standards to name in your specification
Naming the right standards in the RFQ removes a lot of back-and-forth. The ones that come up most in box build are:
- IPC-A-610 for acceptability of electronic assemblies. Revision J was released in 2024. State the class: Class 2 for most commercial and industrial products, Class 3 where high reliability is required.
- IPC J-STD-001 for soldering process requirements.
- IPC/WHMA-A-620 for cable and wire harness assemblies.
- ISO 9001 for the factory quality management system, and ISO 13485 or IATF 16949 where the sector requires it.
- Product compliance: UL, CE, FCC, RoHS and REACH, depending on the market.
Ask each factory for current certificates and check the scope and expiry date on each one. A certificate that covers PCBA at one site does not automatically cover box build at another. For background on how the EMS industry is structured, the Wikipedia article on electronics manufacturing services is a reasonable starting point.
Common mistakes to avoid
- Comparing quotes on different Incoterms. An FOB price and a DDP price are not the same number. Normalise before you compare.
- Leaving test undefined. If the RFQ does not say what the final test checks, each factory will price a different test, and none of them may match what you need.
- Ignoring tooling ownership. Molds and fixtures should be documented as your property with a clear release clause.
- Skipping the pilot lot. A small pilot run proves the process and the mechanical fit before the full order.
- Assuming origin. Get an origin assessment for your HS code before you build the business case on preferential duty.
How boxbuildvn.com fits in
boxbuildvn.com is an independent matching service, not a factory. We do not manufacture, inspect, ship or hold payments. You send your box-build RFQ (BOM, drawings, test spec and volume) and we match it with up to 3 Vietnamese EMS or box-build factories whose capability fits your product. From there, you and the factories work directly on quotes, samples and orders.
It is free for buyers and there is no commission on orders. If you need an NDA before any BOM or design file is shared, ask for one and it is signed before anything goes to a factory. If you are sourcing boards or harnesses only, see EMS contract manufacturing in Vietnam for that scope.
Send your BOM and drawings through the box-build RFQ form and get matched with up to 3 Vietnamese EMS factories within 24 business hours. Free for buyers, NDA on request. If your data package is not complete yet, send what you have through the RFQ form and state the product stage, so the match reflects where the design really is.
Frequently asked questions
Can a Vietnamese factory do the box build if my PCBA is made somewhere else?
Yes. Many box-build lines accept consigned PCBAs from another supplier and handle enclosure, cabling, final test and packing. The catch is responsibility: if a unit fails final test, someone has to decide whether the board or the assembly caused it. Agree on incoming inspection criteria for consigned boards, who pays for rework and how failed boards are returned before the first shipment arrives.
Do I need to visit the factory before placing an order?
It is not mandatory, but most OEMs either visit or send a third-party auditor before a production order of meaningful size. A video walkthrough of the SMT line, test area and warehouse is a reasonable first step during quoting. Before mass production, a physical visit or independent audit that checks process documents, calibration records and traceability is worth the cost.
Who owns test fixtures and enclosure tooling?
Whoever pays for them should own them, and the purchase order or tooling agreement should say so in writing. Injection molds and functional test fixtures are commonly quoted as one-time costs. Ask for tooling to be marked with your company name, listed on an asset register and released to you on request, including the conditions for moving it to another factory.
Can a product with Chinese components be marked Made in Vietnam?
It depends on the destination country's origin rules, not on where the final screw is turned. Many regimes use a substantial transformation test or specific tariff-shift and value-content rules under trade agreements. Simple kitting of Chinese sub-assemblies may not qualify. Get a written origin assessment from a customs broker for your HS code before you commit, and check tariffs at the time of import.
How does boxbuildvn.com matching work and what does it cost the buyer?
You send your RFQ package and we match it with up to 3 Vietnamese EMS or box-build factories whose capability fits the product. You then work directly with those factories on quotes, samples and orders. It is free for buyers, there is no commission on orders and an NDA can be signed before any BOM or design file is shared.