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Components, modules and board assembly

Here the buyer is not a marketplace seller: it is an engineer or a manufacturer. The conversation changes completely, and so does the process.

Cinta de componentes de montaje superficial cargada en un alimentador de una máquina de inserción automática
Componentes de montaje superficial en alimentador de línea SMT · Foto: Wikimedia Commons · CC BY-SA 3.0

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How are electronic components and PCBA services purchased in Shenzhen?

Electronic components are purchased in Shenzhen either through authorized distributors or through the open market of Huaqiangbei, and the difference between the two is traceability. For series production an authorized distributor is the right choice, because it guarantees that the component is original and has lot traceability; Huaqiangbei works for prototypes and small quantities. Board assembly services (PCBA) are contracted with an electronics manufacturing partner that is given the Gerber files and the bill of materials, and the work can be run turnkey, with the manufacturer buying the components, or on component consignment, with the buyer supplying them. Typical assembly MOQ is 10 – 50 boards for prototypes and 500+ for series production.

Category facts

Component sourcing
Authorized distributor for series production; Huaqiangbei for prototypes
PCBA documentation
Gerber files, bill of materials and assembly files
Engagement models
Turnkey (the manufacturer buys) or consignment
Typical assembly MOQ
From 10 – 50 boards for prototypes; 500+ for series production
Main risk
Recycled or re-marked components sold as new
Key verification
Lot traceability and functional testing of the board

Authorized distributor versus open market

In components there are two worlds. The authorized distributor sells original product with lot traceability and documentation; the open market of Huaqiangbei sells everything, including recovered, re-marked or industrial-grade material sold as commercial grade.

For a prototype or a repair, the open market is fast and sufficient. Series production is where the problems appear: a batch of integrated circuits of doubtful origin can pass testing and then fail in the field at a rate that ruins the product's reputation. In this category the recommendation is clear and non-negotiable: for series production, an authorized distributor and documented traceability.

How PCBA work is contracted

The assembly manufacturer needs three things: the Gerber files for the board, the bill of materials with part references and quantities, and the position files for automated placement. With those it can quote.

There are two engagement models. In turnkey the manufacturer buys the components and delivers the assembled and tested board; it is more convenient and shifts purchasing management to them, but also the margin. On consignment you supply the components and they provide only the line; it is cheaper at volume and gives you control over the origin of every part, but it requires you to manage purchasing and to carry the risk of shortages.

Functional testing is what separates a good batch from a bad one

On a board, visual inspection and automated optical inspection detect soldering defects, but they do not detect a counterfeit component or badly flashed firmware. What detects that is functional testing: powering the board and verifying that it does what it is supposed to do.

That requires you, or your engineer, to define the test procedure and the acceptance criteria. Without a defined procedure, inspection is limited to checking that the board is properly soldered, which is necessary but not sufficient. If you do not have the procedure, we can coordinate it with the manufacturer, but the technical criteria have to come from your side.

Certifications and applicable regulation

Every product category has its own regime. This table summarises what each standard requires and what it is for; which one applies to your specific product depends on its classification, and we confirm that before production.

Certifications and applicable regulation
Standard What it covers and why it matters
ISO 9001 Quality management system of the assembly manufacturer.
IPC-A-610 Acceptability standard for electronic assemblies. It defines what counts as a correct solder joint.
RoHS / REACH Substance restrictions in components and in the soldering process.
Batch traceability Documentation of the origin of each component. Critical in series production.
UL / IEC Depending on the destination and the end use of the finished product.

Frequently asked questions

Can I buy original components in Huaqiangbei?

Original components can be found in Huaqiangbei, but there is no guarantee of traceability. The open market mixes original, recovered and re-marked product, and the difference is not visible to the eye. For prototypes and small quantities it is a valid and fast route; for series production the risk of field failure does not offset the saving, and it is better to buy from an authorized distributor with lot documentation.

What files do I need to request a PCBA quote?

The Gerber files for the board, the bill of materials with the reference and quantity of each component, and the placement files for the pick-and-place machine. It is also advisable to send the schematic if the manufacturer is going to carry out fault diagnosis, and the firmware if it has to flash it. With those first three files a quote can already be produced.

Turnkey or consignment?

Turnkey is more convenient: the manufacturer buys the components, carries the supply risk and delivers the tested board. On consignment you supply the components, control their origin and pay less at volume, but you manage the purchasing and absorb the delays. For a first batch turnkey usually makes sense; above a certain volume, consignment pays off.

How do you test that a board works?

With a functional test: the board is powered and verified to execute its function. That requires a defined test procedure and acceptance criteria, which normally come from the customer's side because they depend on the design. Without that procedure, inspection stays at the visual level and does not detect counterfeit components or incorrect firmware.

Tell us what you need to buy

Send us a 1688 link, a photo or a sample of the product, plus your estimated volume. You get back a shortlist of vetted suppliers, a landed price to your warehouse and a realistic production lead time.

We reply within 24 business hours. See how the process works