How to evaluate Chinese factory quality tiers — what separates export-grade OEM factories from domestic suppliers and trading companies.
Not all Chinese factories are equal, and "factory size" is a poor proxy for quality. A 200-person focused operation running a single product category can outperform a 2,000-person general factory on almost every metric that matters: defect rate, documentation, communication, and delivery reliability. What actually differentiates quality levels is process maturity — and that's visible if you know where to look.
The four types of operations you'll encounter
Export-grade OEM factories
These are the operations built specifically to serve international buyers. Observable characteristics:
- ISO 9001 certified with a current certificate (verify the cert number on the certifying body's website — fake certificates exist)
- An actual QA department: dedicated QA engineers, incoming material inspection, in-process checks, final inspection before shipment. Not one person who also does other jobs.
- IPC-A-610 Class 2 or Class 3 compliance documented on their processes — they know what it means and can show you their acceptance criteria
- English-capable project manager assigned to your account, not routed through a sales rep who disappears after the order is placed
- SOPs printed and posted at workstations, not living in someone's head
- An established international client roster they can reference (NDA-protected specifics are fine — they should at least be able to name the industries and rough volume)
The price premium over the next tier is typically 15–25% on assembly cost. For electronics going into consumer products, industrial environments, or anything with a warranty obligation, that premium buys yield rate, documentation, and someone to actually talk to when something goes wrong.
Domestic-market factories
These factories are built for Chinese domestic buyers, where the procurement culture and quality expectations are different. They often have good volume capacity and reasonable equipment, but:
- QC is largely "ship and see" — defects surface at the customer, not at the factory
- Documentation is minimal. You may not receive a proper test report; what you get may be a photo of a technician holding your product
- Communication is in Chinese only, often through WeChat, with response times that depend on whether your intermediary is paying attention
- Their reference clients are domestic brands with different expectations than yours
This isn't necessarily a problem for commodity components where you're inspecting incoming goods yourself and the stakes per component are low. For a finished product or a complex PCBA, the lack of systematic QC means you're absorbing their process problems as your rework cost and warranty liability.
Trading companies presenting as factories
Trading companies in China serve a real market need — they aggregate volume across multiple buyers to meet factory MOQs, they handle logistics, and they provide English communication. The problem is when they present themselves as the manufacturer without disclosing that they subcontract production.
Signs you're dealing with a trader rather than a factory:
- "Our factory" language in communications, but no factory address or only a showroom address
- Unable to answer specific process questions (what reflow profile do you use? what solder paste? what's your AOI coverage?)
- Very fast quote turnaround on complex products — they're not calculating, they're marking up someone else's price
- Unusually flexible on any specification — a real factory pushes back on things that affect their process
Traders can quote competitive prices because they're not carrying the overhead of a real production operation. The cost is you lose direct visibility into production, you can't audit the actual facility, and when a quality problem emerges, you're negotiating through an intermediary who has their own financial interest in the conversation.
A trader can be a legitimate part of your supply chain for standard commodity parts where quality is straightforward and price is the primary variable. For anything custom, complex, or high-stakes, losing factory-direct access is a real risk.
Fly-by-night operations
These are usually discovered after a deposit transfer. The tells are there before you pay, if you look: no verifiable business registration, insistence on wire transfer only with no alternatives, inability to provide any documentation, prices that are simply too far below market to make sense. The most common vector is Alibaba or social media platforms where account verification is minimal.
The defense is simple: verify business registration through official channels before any payment, and never transfer a deposit to a new supplier without an in-person or video-verified audit at minimum.
What to look for on the factory floor
A one-day factory visit, or a professional factory audit, surfaces most of what you need to know. For a complete checklist, the factory audit checklist guide covers 47 specific items to verify. These are the observable signals that distinguish tiers:
Production floor:
- Labeled component bins with part numbers, not loose reels stacked on shelves
- ESD mats, wrist straps, and grounding cords in use at assembly stations — not just present, actually being used
- Clean lines with visible housekeeping standards. Not spotless (a working factory isn't a showroom), but orderly
- Traceability markings on WIP (work-in-progress) batches — they should be able to tell you which batch of components went into which boards
Quality infrastructure:
- QA department that is a real department with its own management structure, not one QC person reporting to production
- Calibrated measuring equipment with calibration stickers showing dates
- Rejection bins that are clearly labeled and isolated from production
- First-article samples retained for reference
Communication quality:
- The factory asks you technical questions during the RFQ process. A factory that accepts your BOM without any questions either doesn't understand your product or isn't planning to build it the way you spec'd. The ones that ask "why are you using this particular IC when there's a newer revision available?" are showing you they actually read the BOM.
- Responses to technical questions are specific and accurate, not vague reassurances
Red flags that override other positive signals:
- They won't allow an audit or require "certification" before you can visit the production floor
- Sample turnaround time is implausibly fast (72 hours for a complex PCBA usually means they assembled it by hand for the demo, not on their line)
- They name-drop major international brands but can't produce a purchase order, NDA-protected reference contact, or any verifiable evidence of that relationship
How factory tier should affect your sourcing strategy
For a prototype or early validation run where you're testing product-market fit and not yet shipping to customers, a domestic-market factory or even a good trading company may be acceptable. The economics of a 100-unit build don't support the overhead of a full export-grade OEM operation.
For anything going to end customers — especially in markets with product liability exposure like the US and EU — you want an export-grade factory with real documentation and real QA. The quality premium pays back in lower defect rates, easier regulatory compliance (factories that have worked with EU importers understand the documentation requirements), and a relationship where problems get surfaced and resolved rather than hidden until it's your problem.
The evaluation process described above is what a systematic on-site audit covers. A step-by-step walkthrough of what that looks like in practice is in what a factory audit actually looks like. The EU startup Bluetooth speaker case is a real example — the factory audit confirmed the supplier was a genuine export-grade OEM operation with IPC-A-610 Class 2 compliance, which was the deciding factor in committing to the 5,000-unit production order. Once you're in production, pre-shipment inspection is the ongoing verification that the factory's process is actually producing what you agreed to — because what a factory does on an audit day and what they do on day 47 of a production run are not always the same thing.
