Resources · 28 October 2026 · by Tom Yi

How to Check a Chinese CNC Supplier in 30 Minutes Before You Pay for an Audit

Before you spend money on samples or an on-site audit, you can rule out a large share of bad suppliers from your desk. These are the first checks we run on every supplier, and most of them are free.

1. Get the Unified Social Credit Code

Every company registered in mainland China has an 18-character Unified Social Credit Code (统一社会信用代码). It appears on the business license. Ask the supplier for a photo of the license; a real company will send it without hesitation.

Then look the company up on the official National Enterprise Credit Information Publicity System (国家企业信用信息公示系统, gsxt.gov.cn). It’s in Chinese, but browser translation works well enough. Confirm that:

• The legal name matches the name on the quote, the bank account and the contract.
• The status is active (存续 / 在业), not cancelled or revoked.
• The registered address is plausible for a machine shop. An office tower address is not.

2. Read the business scope: factory or trading company?

The registered business scope (经营范围) is one of the most useful fields. A machining factory’s scope normally includes words such as:

• 生产 / 制造 / 加工: production, manufacturing, processing

A scope that only mentions 销售 (sales), 贸易 (trading) or 进出口 (import/export) means you are most likely talking to a trading company. That isn’t automatically bad, but you should know who actually makes your parts, and you should audit that factory, not the sales office.

3. Check the insured headcount

Chinese companies file annual reports, and these often include the number of employees covered by social insurance (参保人数). Compare it with what the supplier claims:

Supplier says	Annual report shows	What it suggests
“120 employees, 40 CNC machines”	95 insured	Plausible
“120 employees, 40 CNC machines”	6 insured	Sales office, or production elsewhere

It’s not a perfect measure, because some workers are not insured, but a large gap is a red flag worth asking about.

4. Verify the certificates, not the PDF

A certificate PDF proves nothing on its own. Check it at the source:

• China-issued certificates can be checked on the official certification information platform run under the Certification and Accreditation Administration (CNCA). Search by company name or certificate number.
• IAF CertSearch (iafcertsearch.org) covers certificates from accredited certification bodies worldwide.
• Confirm the scope on the certificate covers machining, the site address matches the factory you’ll buy from, and the expiry date is in the future.

We regularly see certificates that are expired, cover a different site, or come from certification bodies that aren’t accredited at all.

5. Ask for a live video walk-through, on your terms

Pre-recorded factory videos are easy to borrow. Ask for a live video call and direct it yourself:

• Ask them to show the nameplate of a specific machine they listed (brand, model, serial).
• Ask to see the CMM and its latest calibration sticker or certificate.
• Ask them to walk from the machines to the inspection room without cutting the call.

Hesitation or “the camera isn’t working today” tells you a lot.

What desk checks can’t tell you

Desk checks filter out fake and mismatched suppliers. They can’t tell you whether a real factory can hold your tolerances: whether the machines are maintained, whether anyone can program the CMM, how first articles are approved, or which operations are quietly outsourced. That takes an engineer on the shop floor.

Rule of thumb: desk checks for every candidate; an on-site audit for the supplier you’re about to give a production order to.