Shenzhen Alu Rapid Prototype Precision Co., Ltd.
Industry News
Short answer: A good Chinese CNC supplier is not the one with the lowest quote — it is the one that is the factory itself, holds ISO 9001 (and IATF 16949 for automotive), sends material certificates and inspection reports, offers DFM feedback before you order, and will run a paid sample. Verify all five before you commit to volume.
Sourcing in China can cut part cost by 40–60%. It can also go badly wrong. This checklist is what experienced buyers verify before placing a production order.
1. Are You Talking to the Factory or a Trading Company?
Many "manufacturers" are middlemen who subcontract your parts and add a margin. Ask directly, and ask for: a factory address, a video walkthrough of the floor, and the number and type of machines they own. A real factory can answer machine-model and capacity questions instantly.
2. Is the Quality System Real?
Ask for the certificate number, not just the logo. The relevant standards are:
ISO 9001 — the baseline quality system
IATF 16949 — required for automotive parts
ISO 13485 — medical devices
AS9100 — aerospace
Any certificate can be verified with the issuing body. A supplier who hesitates on the number is telling you something.
3. Do They Send Material Certificates and Inspection Reports?
For every order you should receive: the material certificate (mill cert showing alloy and heat number) and a dimensional inspection report (CMM or equivalent) against your drawing. For high-value parts, request first-article inspection (FAI).
4. Do They Offer DFM Feedback Before the Order?
This is the single best predictor of a good supplier. A capable factory reviews your drawing and tells you which features drive cost and how to fix them — often before you have paid anything. A supplier who only says "yes, we can make it" at any price is not adding engineering value.
5. What Are the Realistic Tolerances?
Ask what tolerance they can hold routinely, not what they can achieve once. Typical capability:
| Feature | Typical tolerance |
|---|---|
| General dimensions | ±0.1 mm |
| Tight features | ±0.02 mm |
| Precision fits / bores | ±0.01 mm |
| Surface roughness | Ra 0.8–1.6 µm standard |
See our CNC machining capabilities for the tolerances and finishes we hold as standard.
6. Communication and Response Time
Send a small test RFQ and watch how they respond: how fast, how clearly, in your language, and whether they ask sensible questions about the drawing. If quoting is slow and vague, production and problem-solving will be worse.
7. Will They Run a Paid Sample First?
Always order a paid sample run before volume production — even if you have received photos. It validates tolerance, finish, and packaging, and it is the cheapest way to find problems. Avoid suppliers who refuse sampling or push you straight to a large order.
8. Payment, Lead Time, and Export Experience
Payment: prefer a deposit plus balance on inspection (e.g. 30/70). Be cautious with 100% upfront.
Lead time: get it in writing, including lead time for repeat orders.
Export: ask about HS codes, packing for sea/air freight, and whether they have shipped to your country before.
Traceability: confirm part marking and batch traceability for future orders.
The 8-Point Checklist (Summary)
Factory, not trading company
Verifiable ISO 9001 / IATF 16949 certificate number
Material certificates and inspection reports as standard
DFM feedback before the order
Honest, realistic tolerance capability
Fast, clear, technical communication
Willing to run a paid sample
Reasonable payment terms and export experience
FAQ
Is it safe to source CNC parts from China?
Yes, if you verify the supplier: confirm the factory, the certificate numbers, and the inspection process, and always run a paid sample before volume.
How much cheaper is CNC machining in China?
Typically 40–60% lower than US or European shops for comparable parts, mainly due to labor and supply-chain density.
What is a reasonable MOQ?
For CNC, there is usually no real MOQ — one part is fine. Volume discounts typically start at 10–50 parts.
How do I protect myself on a first order?
Order a paid sample, inspect it, then use deposit-plus-balance payment terms and require an inspection report with the shipment.
Start With a Sample
Send us a drawing and we will return a quote with DFM feedback and a sampling plan — usually within one business day.