Auditing a sheet metal supplier in China is mostly a documentation exercise, because the things that go wrong on a program are usually visible in the records long before they show up in the parts. This page lists what a buyer should ask to see, what each document proves, and what it does not.
Documents First, Impressions Second
A factory tour shows equipment and activity. It does not show whether a drawing revision was frozen before the batch ran, or whether the inspection record was signed. The audit is therefore built around a small set of documents that can be requested in advance and examined against each other.
What to Ask For
| Management system certificate and audit report | Confirms that an external body has assessed the operation. Check the certificate number, the issuing body and the scope — a certificate for a different legal entity or a different scope proves less than it appears to. |
|---|---|
| A first-article inspection report | The single most informative document. It shows whether measured values are compared against a stated requirement, whether the method is named row by row, and whether someone signed and dated it. |
| A material certificate for a recent batch | Confirms the grade actually used and lets the batch be traced. Compare the grade on the certificate with the grade on the drawing for that job. |
| A process route with a revision reference | Shows that the batch was run to a defined revision rather than to the operator’s understanding of the drawing. |
| A packing specification and photographs | What the buyer pays for at the end of the route, and the point where damage is most expensive. |
| A list of outsourced operations | Which steps leave the factory. This is normal in the industry; not stating it is the problem. |
What the Documents Do Not Prove
A certificate does not measure a part. A process route does not guarantee the operator followed it. An inspection report says nothing about the parts that were not inspected. That is why the audit is usually paired with a sample: one part made to the real drawing, with the first-article report issued alongside it, is more informative than a day of meetings.
The same documents are what make an order repeatable after the audit. When a batch arrives later, the report and the approved sample are the reference — which is why the inspection record matters more than a certificate on the wall.
Questions That Are Worth Asking Verbally
- Which operations are done in this building, and which are not?
- Who decides that a drawing is unclear, and who asks the buyer?
- What happens to a part that fails inspection — rework, scrap, or a concession?
- How is a repeat order set up, and what does the operator work from?
- What is outside your capability, and who do you refer that work to?
Answers to those five questions describe an operation more accurately than a gallery of machinery.
What a Sample Order Tells You
One part made to the real drawing, ordered before a program is committed, tests five things at once: whether the drawing was read the way you intended, whether the tolerances are achievable, what the surface quality is actually like, how the part is packed, and how the supplier communicates when something is ambiguous.
The first-article report that comes with it is the evidence. Compare each row against the requirement on your drawing: is the requirement stated, is the method named, is the value inside tolerance, and is the document signed and dated. A report that says “checked, OK” without numbers is a description, not a record. The same standard is applied to every record we issue — see quality inspection.
Questions Buyers Ask About Sheet Metal Supplier
Can we audit the factory before ordering?
Yes. Buyers and third-party inspectors are welcome on site. Send the audit checklist in advance so the relevant records and the parts in production on that day can be arranged.
Which documents can you send before we visit?
The management system certificate and TUV audit report numbers, a sample first-article inspection report, a material certificate for a recent batch and the packing specification can all be shared for review.
What if we find a non-conformity during the audit?
It is reported and answered in writing, with the corrective action stated. An audit that produces no findings at all is usually an audit that looked at too little.
Send the Sheet Metal Supplier Drawing Package
For a useful quotation, send drawings, quantity, material, finish and assembly requirements. Violet Gao will review your project and reply with technical feedback.
Request a QuoteWhat stands behind this quotation
- Manufacturing since 20162,500 m² Ningbo plant — 3 laser cutting machines (including newer TRUMPF), 4 CNC press brakes and 10 welding stations.
- Shipped to more than 30 export marketsEnclosures, cabinets and formed parts supplied to OEM buyers across Europe, North America and Asia.
- 123 documented product casesMedical device housings, HVAC and heat pump enclosures, agricultural and livestock equipment, industrial hydraulics, material handling trolleys and EV charging cabinets.
- Factory evidence you can checkTUV Rheinland audit reference MIC-ASI243729 and Bureau Veritas reference MIC-ASR263630 available for buyer review under NDA.
Before you send drawings: an NDA is signed on request · first-article inspection is carried out before a batch continues · pricing is staged from prototype quantity to repeat volume · pre-shipment photos and packing records are prepared when the project needs them.