CNC Machining in China: A Practical Guide for US & EU OEMs
Sourcing machined parts from China works extremely well for some orders and badly for others. The difference is rarely the country — it's whether the part, the volume and the documentation match what the supplier actually does every day. This page explains how our Shenzhen shop works, what we hold, what things cost, and how to tell a good China machining partner from an expensive lesson.
What we do
ROK Precision is a CNC machining factory in Bao'an, Shenzhen, supplying custom machined and turned parts to OEMs in North America and Europe. One team quotes, machines, inspects and ships — no trading company in between:
- 3-, 4- and 5-axis CNC milling — housings, brackets, manifolds, fixtures, enclosures
- CNC turning — shafts, bushings, fittings, threaded components, up to Ø320 mm
- Mill-turn and secondary operations — cross-drilling, broaching, threading, assembly
- Surface finishing — anodizing (Type II/III), passivation, plating, black oxide, heat treat
- Materials — aluminum (6061, 7075, 2024, 5052), stainless (303, 304, 316, 17-4PH), titanium, brass, copper, engineering plastics (PEEK, POM, nylon, PTFE)
Standard capability is ±0.1 mm; we hold ±0.005 mm on critical features with 100% CMM verification. Full capability details: CNC machining tolerances explained.
Who China machining makes sense for
| Situation | China (our shop) | Local US/EU shop |
|---|---|---|
| Prototype, 1–10 pcs, needed in days | Viable — express shipping 3–5 days | Usually faster overall |
| Low-volume production, 50–1,000 pcs | Typically 30–50% cheaper at equal quality | Price rises sharply with batch setup |
| Production runs, 1,000–50,000 pcs | Strong advantage, especially turned parts | Often subcontracted anyway |
| ITAR / defense-controlled work | Not applicable | Required |
| Parts needing frequent engineering changes in person | Possible, but video calls replace visits | Advantage local |
What our quotes actually include
Every quote we send answers the questions that cause disputes later:
- Unit price and tooling — clearly separated; no hidden setup fee after PO.
- Lead time — machining days plus shipping days, stated separately.
- Material origin — mill certificates available; we flag when a substitute alloy is cheaper and functionally identical.
- Inspection level — sampling or 100% CMM on critical features, your choice.
- Shipping terms — we quote DDP to the US, Canada, UK and EU: duties and clearance handled, no surprise invoices from the courier.
How the process runs, drawing to delivery
- You upload the drawing (STEP + PDF is ideal) at our RFQ page. The file goes straight to our engineers, not to a sales inbox queue.
- Within 6 working hours you get a quote — and more importantly, DFM feedback: which features drive cost, where tolerance is over-specified, where a material swap saves money.
- PO confirmed → material ordered → machining scheduled. First-article photos go out on request before the full batch runs.
- Inspection report + parts ship by your chosen method, tracking shared the day they leave.
Common objections, answered plainly
"Communication will be painful."
With trading companies, often yes. With a factory that assigns one English-speaking engineer to your account from RFQ to delivery, it's closer to working with any remote team. Our quote arrives with named contacts, not a generic address.
"Quality can't be verified remotely."
It can — if the supplier documents instead of promising. Ask for a CMM report on critical dimensions with the first shipment, then decide whether to require it every time. Reports cost minutes; trust built on them lasts years.
"Tariffs make it pointless."
Section 301 tariffs add cost to many categories, but the landed price of Chinese machined parts frequently remains below the ex-works price of US quotes for the same drawing. We quote DDP, so you compare one number against one number — no math homework.
Frequently asked questions
How fast can I get a quote?
Within 6 working hours for standard parts. Complex assemblies or multi-process jobs may take a day, and we'll say so immediately rather than let a quote sit.
What's the minimum order?
There is no strict MOQ. Single prototypes ship regularly; pricing gets dramatically better from 50 pieces up as setup amortizes.
Do you ship DDP?
Yes — DDP to the US, Canada, UK and EU is our default recommendation. Duties, clearance and last-mile are included in the quoted price.
Can you sign an NDA?
Yes, and we'll counter-sign yours or send ours. Drawings stay inside the engineering team that quotes them.
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