Verify Chinese CNC Factory: 10 Questions to Ask Before Sending CAD
How to verify Chinese CNC factory partners — an engineer’s checklist by people who’ve been on both sides of the table.
If you’re sourcing CNC machining from China, knowing how to verify Chinese CNC factory suppliers is the difference between a reliable supply chain and an expensive mistake. We’ve evaluated suppliers as engineers, and been evaluated by customers as a factory. These 10 questions are what we wish every engineer asked. Below each question, we give our own answer. Use this framework to verify any Chinese CNC factory — including us.
Jump to:
- 1. Technical questions before quoting
- 2. Equipment with serial numbers
- 3. Tolerances you can actually hold
- 4. Downloadable ISO certificate
- 5. Customer references
- 6. Quality consistency
- 7. On-time delivery rate
- 8. IP protection
- 9. Minimum order quantity
- 10. Response speed
1. Do you ask technical questions before quoting?
Why it matters: A factory that quotes without questions doesn’t understand your part. When you verify a Chinese CNC factory, this is the fastest filter — if they don’t ask about wall thickness, undercuts, or surface finish, they’re optimizing for speed, not quality.
QDJ answer: We never quote without a DFM review first. Before any number, our engineers check every critical dimension and flag issues with suggested fixes — before you spend a dollar. See our CNC machining service →
2. Can I see your equipment — with serial numbers?
Why it matters: Factory photos are easy to borrow. Real Chinese CNC factory verification means seeing equipment with visible serial numbers and production logs.
QDJ answer: Our equipment list is public: 5-axis DMG Mori, 4-axis Haas VF-2, Citizen Swiss-type lathes, Zeiss CMM. We’ll show you serial numbers and maintenance logs for any machine that touches your parts. Factory visits welcome — Dongguan, Chang’an.
3. What tolerances can you actually hold?
Why it matters: “±0.01mm” on a website means nothing. To properly verify Chinese CNC factory claims, ask for real inspection data — what they deliver consistently, across batches.
QDJ answer: Guaranteed: ±0.02mm for CNC machining, ±0.05mm for 3D printing. Every batch ships with a Zeiss CMM inspection report. Tighter than ±0.01mm? We’ll tell you honestly if we can or can’t. See our 3D printing service →
4. Can I download your ISO certificate?
Why it matters: ISO logos are free to download. A serious Chinese CNC factory makes their certificate available as a PDF with certificate number, issuing body, scope, and expiration date.
QDJ answer: ISO 9001:2015 certified by SGS, valid through 2027. Download our certificate. Our QMS follows ISO 9001:2015 standards. We also hold CE and RoHS compliance documentation — ask for the specific standard numbers for your product.
5. Who else have you manufactured for?
Why it matters: Not logos on a page. To properly verify a Chinese CNC factory, you need named references with LinkedIn profiles — people you could theoretically contact.
QDJ answer: Our customers include hardware teams at Xylem, Volkswagen, Siemens, Philips, and Aston Martin — plus dozens of startups shipping products globally. Each testimonial has a named contact. We’ll facilitate introductions on request. Read customer feedback →
6. What if quality drops after the first order?
Why it matters: The #1 fear when sourcing from China. A genuine verify Chinese CNC factory process checks for First Article Inspection Reports (FAIR) — non-negotiable for quality consistency.
QDJ answer: Every run starts with FAIR approval before we proceed. In-process inspection, not just final inspection. If something goes wrong, we fix it at our cost — and change the process so it doesn’t happen twice.
7. What’s your actual on-time delivery rate?
Why it matters: “We deliver on time” is meaningless. A factory worth trusting publishes their OTD data. This single metric tells you more about a Chinese CNC factory than any marketing copy.
QDJ answer: 94% OTD over the last 12 months. We track every order’s promised vs. actual ship date — using methodology aligned with supply chain industry standards. Delays happen — when they do, we notify you within 24 hours with a revised date and reason.
8. How do you protect my IP?
Why it matters: Intellectual property theft is the #2 fear engineers have about Chinese suppliers. NDA, encrypted file storage, and employee contracts must be verifiable — not just promised.
QDJ answer: NDA before CAD review. Your files stay on encrypted, access-controlled servers. Only assigned engineers see them. Employee contracts include IP protection. Zero IP incidents since 2010.
9. What’s your minimum order quantity?
Why it matters: If you’re prototyping, “MOQ 1000 pcs” is useless. The right Chinese CNC factory for hardware teams accepts 1pc prototype runs.
QDJ answer: No minimum. 1 piece prototype? Yes. 50 pieces for pilot? Yes. 10,000 for production? Yes. We price transparently — you pay for the work, not for hitting arbitrary volume.
10. How fast do you respond?
Why it matters: A factory that takes 3 days to reply takes 3 weeks to fix a quality issue. Response time is the best predictor of problem-solving speed when you verify a Chinese CNC factory.
QDJ answer: 5-minute response during business hours (GMT+8, 8:00–22:00). DFM review within 24 hours. Quote within 48 hours. Email at 3am your time, wake up to a reply.
Verify Chinese CNC Factory Partners — Stop Guessing, Start Verifying
Send your CAD. We’ll complete a free DFM review — you get a detailed engineering analysis, not a sales pitch. Use our framework above to verify us against any other Chinese CNC factory. If our analysis makes the most sense, we’ll earn your business. If not, you’ll still have a better understanding of your part.
That’s how you verify Chinese CNC factory partners — and find a real engineering partner.