How to Verify Sheet Metal Supplier: 6-Step Checklist

By Jessica Cui · Reviewed by Matthew Wu · Last updated 2026-10-15

This checklist helps you verify sheet metal supplier in about one hour. Most failed first orders in sheet metal trace back to skipped supplier checks. This checklist takes about one hour and covers the checks that matter.

Step 1 — Registration Entity

Ask for the business license and check the registered name. The export contract, invoice and website must name the same registered company. A mismatch between website brand and trade entity is the first red flag.

Step 2 — ISO Certificate, Not a Claim

An ISO 9001 claim on a website is not proof. Get the certificate number and check it with the issuing body. Confirm the certificate holder is the company that signs your contract. Example: Cangzhou Xinjiuxinji Import And Export holds ISO 9001:2015, certificate ZTZL28025Q1049R0S, and anyone can verify it with the issuer.

Step 3 — Capacity Evidence

Ask for a current equipment list with tonnage and size. Request a live video call on the shop floor. A real factory schedules the call without friction. Our Nanpi factory keeps 40+ presses from 60T to 400T and welcomes live calls.

Step 4 — Sample Policy

Ask what a sample requires: file format, lead time and cost. A clear answer shows a working sample process. A vague answer shows one that does not exist.

Step 5 — Engineering, Not Just Sales

Send one drawing with a real question on it. Watch who answers. An engineering team discusses material, bend radii, tolerance and tooling. A sales-only team discusses price only. Our factory employs 19 engineers for exactly this review.

Step 6 — Audit and Track Record

Ask for export history to your market and references. Third-party audits are available, and we have passed them. Check the platform store record and years of export.

Checklist Summary

FAQ

How do I check if an ISO certificate is real? Ask for the certificate number and verify it with the issuing body. The holder name must match the company that signs your contract.

Should I pay for a third-party factory audit? For first orders of meaningful value, yes. Auditors check equipment, QC and capacity against the supplier’s claims.

Can I visit the factory in China? Yes. Nanpi is close to Beijing and Tianjin, so travel is straightforward. A video audit is a good first step.

What documents should a supplier send before sampling? An equipment list, the ISO certificate, the sample policy and one comparable part they have made.