# How to Verify a China CNC Supplier: 10-Point Checklist with Our Evidence > A practical 10-point checklist for verifying a China CNC supplier — factory, certificates, CMM reports, EN 10204 3.1 traceability, FAI, subcontracting, NDA, MOQ, consistency and export evidence — with our own answers and links for every point. https://www.sinbo-machining.com/wiki/quality/verify-china-cnc-supplier/ --- ## On This Page - Why "Verify the Supplier" Is the First Step in China Sourcing - The 10-Point Checklist at a Glance - 1. Do They Manufacture In-House, or Are They a Trading Company? - 2. Are Their Certifications Real? How to Check - 3. Can They Provide Real CMM Inspection Reports? - 4. Is Material Traceable to the Heat Number? - 5. Do They Run First Article Inspection (FAI)? - 6. Do They Disclose Subcontracting? - 7. Will They Sign an NDA — Before Seeing Your Drawings? - 8. Is the MOQ Real, and What Drives It? - 9. How Do They Stay Consistent from Sample to Production? - 10. Do They Have Export Experience and Checkable References? - Red Flags That Should Stop a Payment - Standards & Sources - Frequently Asked Questions - Get the Checklist Answers for Your Own RFQ # How to Verify a China CNC Supplier: 10-Point Checklist, Answered with Our Own Evidence When you buy machined parts from a supplier 8,000 km away, you cannot walk the floor before every order — verification has to happen through documents, databases and samples, and that is exactly where unqualified suppliers fail. This page publishes the 10-point checklist every buyer should run before the PO, and then answers each point with our own verifiable evidence and links, so you can run the checklist on us before you send a drawing. ## Why "Verify the Supplier" Is the First Step in China Sourcing When you buy machined parts from a supplier 8,000 km away, you cannot walk the floor before every order. Verification has to happen through documents, databases and samples — and that is exactly where unqualified suppliers fail. Certificate scans can be photoshopped or borrowed from a previous audit, dimensional claims can be marketing numbers with no inspection report behind them, and a glossy website can belong to a trading company that subcontracts your parts to a workshop you never saw. The result of skipping verification is expensive and predictable: rejected lots at incoming inspection, material that cannot be certified to EN 10204 3.1, automotive programs that fail a PPAP review, or an NDA that was never signed before your drawings travelled. This page does something unusual: it publishes the checklist we would want every buyer to run — and then answers each of the ten points with our own verifiable evidence and links, so you can run the checklist on us before you send a drawing. Most of the methodology below is standard sourcing practice and the audit logic of ISO 9001, IATF 16949 and AS9100; where a rule is standard-specific we name the standard so you can re-verify it yourself. ## The 10-Point Checklist at a Glance | # | Verify | Evidence to Collect Before the PO | 1 | Real factory, not a trading company | Legal name, factory address, business registration match | 2 | Certifications are real and in scope | Certificate numbers, scope statement, registrar check | 3 | Dimensional claims backed by CMM reports | Sample CMM report: nominal/actual/tolerance, datum scheme | 4 | Material traceable to the heat | EN 10204 3.1 mill certificate for the actual batch | 5 | FAI before any production batch | FAI plan in the quotation, AS9102-format sample | 6 | Subcontracting disclosed in writing | In-house vs sub-tier process list, sub-tier accreditation | 7 | NDA signed before drawings travel | Signed NDA, then — and only then — the CAD package | 8 | MOQ stated in writing with a reason | Written MOQ per process and the cost driver behind it | 9 | Consistency from sample to production | Control plan, SPC/Cpk data, batch inspection records | 10 | Export experience and checkable references | Export packing and documentation evidence, case studies ## 1. Do They Manufacture In-House, or Are They a Trading Company? The most common failure mode in China sourcing is not a bad factory — it is no factory at all. Trading companies resell your parts to workshops you never audited, and every verification you performed applies to the middleman, not to the machines cutting your metal. The standard checks: match the supplier's legal entity name against China's public National Enterprise Credit Information Public Registry, confirm the factory address on the quote is the address on the business license, and ask which manufacturing steps happen in-house and on whose equipment. Equipment brands and counts are a good cross-check — a shop claiming 5-axis precision work should be able to name the machines. We are the factory. Sinbo Precision was founded in 2013 and runs a 34,000 m² operation in Huangjiang, Dongguan — in the middle of the Pearl River Delta manufacturing hub — with 632 employees and 518 machines, including Makino, Mazak, Tsugami and Star precision equipment across four locations. Our two Dongguan factory addresses are published on our contact page: Factory 1 at No. 7, Mingzhu 2nd Road, Shebei, and Factory 2 at No. 19, Mingzhu 1st Road, Shebei. Ask us anything about the equipment list and we will answer against the machines, not a brochure. A video call or an on-site visit can be arranged on request through our contact page. [Evidence on our site: About us ](https://www.sinbo-machining.com/about/)[· Contact and factory addresses ](https://www.sinbo-machining.com/contact/) ## 2. Are Their Certifications Real? How to Check [A certificate scan proves nothing by itself — certificates get photoshopped, recycled after expiry, or issued by bodies nobody recognizes. The working method: ask for the certificate number and full scope statement, then verify with the issuing registrar or the accreditation database for that standard. For AS9100 specifically, every valid certificate must be registered in the IAQG OASIS database, and the certification body must be on the IAQG ICOP recognized list — our guide to verifying a China CNC supplier's AS9100 certificate ](https://www.sinbo-machining.com/wiki/quality/verify-as9100-certificate-real/)walks the three-step process and the four common fraud patterns. For any ISO standard, check that the scope statement covers your process, material and the actual manufacturing address, and re-verify before every new purchase order, not just at qualification. Our certificates: ISO 9001:2015 — with a certification scope that explicitly covers precision manufacturing of CNC machined parts, injection molded components, rapid prototyping services and assembly operations for automotive, medical, aerospace and industrial applications — plus IATF 16949:2016 for automotive, ISO 14001:2015 for environmental management, and SA 8000:2014 for social accountability. All are published on our certifications page together with our High-Tech Enterprise and "Little Giant" enterprise recognitions. [Evidence on our site: Our certifications ](https://www.sinbo-machining.com/about-us/certification/)[· Verify AS9100 certificate guide ](https://www.sinbo-machining.com/wiki/quality/verify-as9100-certificate-real/)[· Certifications decision guide ](https://www.sinbo-machining.com/wiki/quality/certifications/) ## 3. Can They Provide Real CMM Inspection Reports? [If a supplier cannot show a dimensional inspection report from a coordinate measuring machine, they cannot prove tolerance — they are guessing. A real CMM report shows more than green checkmarks: nominal, actual and tolerance per feature, the datum scheme it was measured against, the measurement method and probe strategy, temperature at measurement, and the equipment identity with its calibration status. Ask for a sample report on a part similar to yours — marketing roundness ("±0.005 mm!") without inspection data behind it is exactly the kind of claim our guide on why CNC parts get rejected by CMM ](https://www.sinbo-machining.com/wiki/quality/parts-rejected-by-cmm/)tells you to test, because a part that passes the supplier's CMM can still fail yours if the measurement plan differs. [We run CMM and optical inspection equipment rated to ±0.001 mm measurement accuracy, holding machining tolerances to ±0.005 mm, and we document the measurement method, temperature, probe strategy and datum scheme on every FAI — so what we ship is what your incoming inspection sees. Quality reports, including measurement data and inspection certificates, are delivered with every shipment rather than on request. Our full measurement toolkit is described in the quality assurance service ](https://www.sinbo-machining.com/services/quality-assurance/)[and the CNC part measurement guide ](https://www.sinbo-machining.com/wiki/quality/measurement/). [Evidence on our site: Quality assurance service ](https://www.sinbo-machining.com/services/quality-assurance/)[· Why parts get rejected by CMM ](https://www.sinbo-machining.com/wiki/quality/parts-rejected-by-cmm/)[· Measurement methods guide ](https://www.sinbo-machining.com/wiki/quality/measurement/) ## 4. Is Material Traceable to the Heat Number? [For automotive, medical, aerospace and pressure applications, untraceable material is rejected material. The standard is EN 10204: a Type 2.2 certificate carries non-specific results drawn from statistical data, while a Type 3.1 certificate states the actual chemistry, tensile, yield, impact and hardness results for your specific heat, signed by the mill's authorized inspector — and Type 3.2 adds verification by an independent inspection agency for the most critical work. Two verification habits matter as much as the certificate itself: cross-check the heat number on the certificate against the number stamped on the physical material, and make sure the supplier maintains traceability from raw stock through every sub-tier operation to delivery. Our EN 10204 3.1/3.2 buyer guide ](https://www.sinbo-machining.com/wiki/quality/en10204-material-certificate-guide/)covers the five certificate mistakes we see most often. We supply CNC machined parts with full EN 10204 3.1 mill certificates — chemistry, mechanical properties, heat-number traceability and authorized-inspector sign-off — and for PED Category III/IV parts we can arrange 3.2 through third-party inspection agencies. Traceability runs from raw material to finished product: each batch is tracked with material certificates, inspection records and quality reports that ship with the order. On sheet metal work, EN 10204 3.1 certificates are issued for steel and aluminium as standard. [Evidence on our site: EN 10204 certificate guide ](https://www.sinbo-machining.com/wiki/quality/en10204-material-certificate-guide/)[· Quality assurance service ](https://www.sinbo-machining.com/services/quality-assurance/)[· Sheet metal fabrication ](https://www.sinbo-machining.com/services/sheet-metal-fabrication/) ## 5. Do They Run First Article Inspection (FAI)? [First article inspection is the gate between a verified setup and an unverified bet: a full dimensional and material verification of the first part off the production setup, before the rest of the batch is cut. In aerospace work it follows the AS9102 format, and the most common FAI rejections are paperwork failures — incomplete form fields, unbalanced mirroring of drawing revisions, missing accountability rows — rather than bad parts; our guide to AS9102 FAI rejection reasons ](https://www.sinbo-machining.com/wiki/quality/as9102-fai-rejection-reasons/)lists the twelve we see most. The buyer-side check is simple: the FAI plan should appear in the quotation as part of the process, not appear later as an extra invoice line, and the report should state how each dimension was measured — not just the result. FAI is standard in our process. Our quality team prepares AS9102-compliant FAI packages for aerospace orders, and on sheet metal work every job ships with a FAI report on the first batch plus in-process sampling on roughly 10% of production pieces. FAI reports document the measurement method, temperature, probe strategy and datum scheme, which is why our parts survive the customer's CMM, not just ours. First-article and production validation inspections are also part of our production tooling service. [Evidence on our site: AS9102 FAI rejection reasons ](https://www.sinbo-machining.com/wiki/quality/as9102-fai-rejection-reasons/)[· Quality assurance service ](https://www.sinbo-machining.com/services/quality-assurance/)[· Sheet metal fabrication ](https://www.sinbo-machining.com/services/sheet-metal-fabrication/) ## 6. Do They Disclose Subcontracting? Subcontracting itself is not the problem — undisclosed subcontracting is. Aerospace rules say it plainly: AS9100 allows a CNC shop to subcontract special processes such as heat treatment, NDT or chemical processing, provided the sub-tier holds current accreditation for that specific process, the shop maintains material traceability through all sub-tier operations, and the buyer can verify the sub-tier's status independently. That is the standard hybrid model for aerospace work from China — machining in-house, accredited sub-tiers for special processes — and a supplier who cannot or will not name which processes stay in-house is telling you something. Get the in-house vs sub-tier list in writing, and verify the accreditations yourself. [Here is our written answer: precision machining is done in-house on our own equipment, and special processes — heat treatment, NDT and chemical processing — are routed to Nadcap-accredited sub-tier partners, with full material traceability from raw stock through final delivery. On sheet metal work, surface treatment (powder coating, e-coating, hot-dip galvanizing, brushing and blasting) runs through established partner factories we have used for years, so finishing is repeatable across reorders rather than a different shop each time. We publish this model openly — including how buyers should verify it — in our guide to Nadcap-accredited CNC suppliers in China ](https://www.sinbo-machining.com/wiki/quality/nadcap-accredited-cnc-suppliers-china/). [Evidence on our site: Nadcap suppliers guide ](https://www.sinbo-machining.com/wiki/quality/nadcap-accredited-cnc-suppliers-china/)[· Sheet metal fabrication ](https://www.sinbo-machining.com/services/sheet-metal-fabrication/) ## 7. Will They Sign an NDA — Before Seeing Your Drawings? Intellectual property protection starts with a signed agreement, not a verbal promise. The working practice is to send the NDA first and the drawings second: agree on scope (drawings, CAD files, quantities, end-use restrictions), sign, and only then release the design package. A supplier who hesitates, proposes "we keep all customer files confidential" instead of signing, or asks for the drawings "to prepare the quote first" is showing you how your design data will be handled for the life of the program. For regulated buyers, NDA obligations often extend into the supply-chain compliance paperwork — human-rights and environmental clauses in supplier agreements — so it is worth asking what compliance documents the supplier already supports. We sign NDAs on request — NDA support is listed explicitly in our supply chain compliance documentation, alongside EN 10204 3.1 certificates, RoHS/REACH declarations and first article inspection. As a China-based manufacturing partner we also actively support customer due-diligence obligations, including the German Supply Chain Due Diligence Act (LkSG) and the supplier ESG platforms used by European buyers (Provigis and EcoVadis self-assessments), with supplier risk-analysis questionnaires and contractual human-rights and environmental clauses accepted in supplier agreements. [Evidence on our site: Certifications and supply chain compliance ](https://www.sinbo-machining.com/about-us/certification/) ## 8. Is the MOQ Real, and What Drives It? Ask what the minimum order quantity actually is — in writing, per process — and what drives it: setup cost or policy. The two give different answers. A MOQ grounded in setup economics tells you the supplier thought about your part; a policy MOQ with no explanation often just filters small buyers out. For prototypes, a MOQ of one piece on the right process is a genuine capability signal, because it means the shop runs the same controlled process for a single part as for a production batch — same equipment, same fixtures, same operators. The trap to avoid is a supplier whose published numbers contradict each other between pages; consistency in the small things predicts consistency in the big ones. Our numbers, in one place: prototype quantities from 1 piece, production quantities from 100 pieces depending on complexity — the published range across our low-volume manufacturing service is 1–10,000 parts. On the fiber laser cutting line the MOQ is 1 piece on 3000 × 1500 mm beds, and the same applies across our sheet metal service: same equipment, same fixtures and same welders whether you order 1 piece or 1,000, with the FAI report and material certificates included either way. Standard CNC turnaround is 3–5 business days, with 1–2 day rush service for urgent projects. [Evidence on our site: CNC machining service ](https://www.sinbo-machining.com/services/cnc-machining/)[· Low volume manufacturing ](https://www.sinbo-machining.com/services/low-volume-manufacturing/)[· Sheet metal fabrication ](https://www.sinbo-machining.com/services/sheet-metal-fabrication/) ## 9. How Do They Stay Consistent from Sample to Production? A perfect prototype followed by drifting batches means the sample was luck, not process. Consistency is engineered, and the evidence lives in the automotive core tools: a control plan that carries inspection points from first article into production, statistical process control with capability indices (the automotive benchmark is Cpk ≥ 1.33, or 1.67 for critical features), in-process inspection at defined frequencies, and batch-level traceability that lets you pull the records for any shipment months later. The buyer-side test we recommend: ask how process parameters and inspection plans carry from FAI to serial production — and for an existing part number, ask for the inspection records of the last three batches. [Our system is anchored by IATF 16949:2016, the automotive quality standard that mandates exactly this machinery — PPAP, APQP, FMEA, SPC and MSA. We run real-time SPC monitoring through production, maintain complete traceability from materials to finished products, and currently run PPAP for an active German Tier-1 automotive program; we have also passed a German Tier-1 VDA 6.3 process audit, the audit German OEMs use to score a supplier's actual process discipline. Batch inspection records for shipped part numbers are retained and available on request. If your team ever needs to respond to an audit finding, we work from the same playbook — see our IATF 16949 audit response guide ](https://www.sinbo-machining.com/wiki/quality/iatf16949-audit-action-items-response/)[and VDA 6.3 checklist ](https://www.sinbo-machining.com/wiki/quality/vda63-process-audit-checklist/). [Evidence on our site: PPAP submission guide ](https://www.sinbo-machining.com/wiki/quality/ppap-submission-cnc-automotive/)[· VDA 6.3 audit checklist ](https://www.sinbo-machining.com/wiki/quality/vda63-process-audit-checklist/)[· Quality assurance service ](https://www.sinbo-machining.com/services/quality-assurance/) ## 10. Do They Have Export Experience and Checkable References? Export experience shows up in details a domestic-only shop never learns: export-grade packing, commercial documentation, and the logistics of moving goods from a factory floor to a port. It also shows up in compliance readiness — European buyers increasingly bring supply-chain due-diligence obligations (questionnaires, ESG platform registrations, contractual clauses) that a first-time exporter cannot answer. For references, the strongest evidence is specific and verifiable: named programs, industries and part families rather than "trusted by global brands", plus third-party registration data that confirms the company is who it says it is. Real case studies with materials, processes and tolerances are checkable; logo walls are not. We manufacture for buyers across automotive, medical, semiconductor, HVAC, oil and gas and general industrial markets, and our case studies document the details — for example, brake discs and steering components machined per drawing for auto-aftermarket makers with material traceability and export packing, or sheet metal brackets shipped with FAI on every batch. Our Dongguan location sits in the Pearl River Delta with easy access to major ports and airports for international shipping, and we support customer due-diligence processes including LkSG and Provigis/EcoVadis platform registrations. Our parts directory of 515+ machined part families, with materials, processes and tolerances per part, gives you a checkable picture of what we machine every day. [Evidence on our site: Auto aftermarket case study ](https://www.sinbo-machining.com/case/tw-auto-aftermarket/)[· Parts directory ](https://www.sinbo-machining.com/parts/)[· Certifications and supply chain compliance ](https://www.sinbo-machining.com/about-us/certification/) ## Red Flags That Should Stop a Payment Each red flag below maps to a checklist point above. One flag means ask questions; two or more means walk away. | Red Flag | Checklist Point | Why It Fails | Factory address on the quote does not match the business registration | 1 | You are buying from a middleman, not the machines | Certificate scan with no number, no scope statement, or an unverifiable registrar | 2 | Forged, expired or out-of-scope certificates are the most common fraud pattern | Marketing tolerance claims with no sample CMM report behind them | 3 | The supplier cannot prove conformity — you will discover it at incoming inspection | Certificate for "a similar grade" instead of an EN 10204 3.1 cert for the actual heat | 4 | Non-specific test data cannot enter automotive, medical or pressure supply chains | FAI offered only as a paid extra after you ask | 5 | The supplier treats verification as an obstacle, not a process step | Refuses to say which processes are in-house vs sub-tier | 6 | Your parts may be made in a workshop you never audited | Hesitates to sign an NDA before receiving drawings | 7 | Your design data will be handled exactly as casually as your NDA request was | MOQ changes between emails, or no written MOQ at all | 8 | Terms that shift before the PO will shift again after it | "Same process" claims with no control plan, SPC data or batch records | 9 | Sample was luck; production is a lottery | No export packing evidence, no case studies, no verifiable registration | 10 | A first-time exporter learns on your order ## Standards & Sources Primary standardsISO 9001:2015 Quality management systems — the baseline certificate and the audit logic behind the scope checks in points 2 and 9.IATF 16949:2016 Automotive QMS — mandates the core tools (PPAP, APQP, FMEA, SPC, MSA) cited in point 9; the Cpk ≥ 1.33 benchmark.AS9100D Aerospace QMS — source of the subcontracting and sub-tier traceability rules cited in point 6, and of the OASIS/ICOP certificate checks in point 2.SAE AS9102 Rev C Aerospace First Article Inspection Requirement — the FAI format cited in point 5.EN 10204:2004 Metallic products — types of inspection documents (2.2 / 3.1 / 3.2) cited in point 4. Databases and toolsNational Enterprise Credit Information Public Registry China's public business registration database — the legal-entity and address check in point 1.IAQG OASIS Online Aerospace Supplier Information System — authoritative AS9100 certification status database.IAQG ICOP Certification body recognition scheme for aerospace QMS.PRI eAuditNet Nadcap accreditation database — verify sub-tier special-process status in point 6. ## Frequently Asked Questions #### How do I verify a China CNC supplier before paying? Run the 10-point check before the deposit: match the legal entity and factory address against China's public business registry, verify certificate numbers and scope with the registrar, request sample CMM and EN 10204 3.1 documents, confirm FAI and subcontracting policy in writing, sign the NDA before drawings travel, and get MOQ and consistency evidence on paper. This page answers all ten points for our own operation with links. #### What certificates should a China CNC machining supplier hold? The baseline is ISO 9001:2015. Automotive supply-chain work requires IATF 16949:2016 — every major OEM mandates it — and aerospace requires AS9100 with the scope and certification body independently verified. We hold ISO 9001:2015 (scope covering CNC machining, molding, prototyping and assembly for automotive, medical, aerospace and industrial applications), IATF 16949:2016 and ISO 14001:2015, plus SA 8000:2014. #### How can I tell a real factory from a trading company? Cross-check three things: the legal entity name in China's public business registry, the factory address against the business license, and the named equipment list. We publish both Dongguan factory addresses on our contact page, and we machine in-house on 518 machines including Makino, Mazak, Tsugami and Star equipment. #### What should I check on a supplier's ISO or AS9100 certificate? Four things: the status (current, not suspended or withdrawn), the certification body (accredited and, for AS9100, on the IAQG ICOP recognized list and registered in OASIS), the scope statement (does it cover your process, material and location), and the expiry date against the surveillance cycle. Re-verify before every new purchase order — our AS9100 verification guide shows the three-step process. #### Will you sign an NDA and provide EN 10204 3.1 certificates? Yes to both — NDA on request and EN 10204 3.1 mill certificates with heat-number traceability are listed in our compliance documentation, alongside FAI and RoHS/REACH declarations; for PED Cat III/IV parts we arrange 3.2 through third-party inspection agencies. Send the NDA first, drawings second. #### What is your MOQ for prototypes and production? Prototype quantities from 1 piece; production quantities from 100 pieces depending on complexity, within a 1–10,000 part range on our low-volume service. Fiber laser cutting and sheet metal work run a 1-piece MOQ with FAI and EN 10204 3.1 certificates included, and standard CNC turnaround is 3–5 business days. Sources & Standards Referenced 1- ISO 9001:2015: Quality management systems — Requirements, International Organization for Standardization 1- IATF 16949:2016: Automotive quality management system standard, International Automotive Task Force — core tools and Cpk benchmarks 1- AS9100D: Aerospace Quality Management Systems, SAE International (2016) — subcontracting and sub-tier control requirements 1- SAE AS9102 Rev C: Aerospace First Article Inspection Requirement, SAE International (2023) 1- EN 10204:2004: Metallic products — Types of inspection documents, CEN — Type 2.2 / 3.1 / 3.2 definitions 1- VDA 6.3:2016: Process Audit, VDA QMC — German OEM supplier process audit referenced in point 9 1- LkSG: German Supply Chain Due Diligence Act — supply-chain due-diligence obligations referenced in points 7 and 10 1- National Enterprise Credit Information Public Registry: China's public business registration database used in point 1 1- IAQG OASIS database and ICOP recognized certification body list: authoritative AS9100 certificate verification sources ## Get the Checklist Answers for Your Own RFQ [Use this page as your qualification script — and hold us to it. Ask us for any item on the checklist: our certificates, a sample CMM report and FAI package, EN 10204 3.1 documentation, our in-house vs sub-tier process list, or a signed NDA before your drawings leave your inbox. For factory audits, the addresses are on our contact page ](https://www.sinbo-machining.com/contact/)and visits can be arranged through it. Send your drawing and verification requirements — we will return a quotation with the FAI plan, material certificate terms and inspection documentation stated up front. [Request a Quote ](https://www.sinbo-machining.com/quote/)